water wheel turbine

7/24/2019 Water wheel turbine

1/138

Water-supply and

Irrigat ion

P s . p f ? N u . 1 8 0 S er m

M ,

G e n e r a l H ydrographic Invest igations, 1 8

DEPARTMENT OF THE INTERIOR

U N IT E D ST AT E S

GEOLOGI CAL

SU RV E Y

CHARLES D. WALCOTT,

DlKECTO

TURBINE WATER-WHEEL

TESTS

AND

POWER TABLES

BT

ROBERT

E HORTON

WASHINGTON

GOVERNMENT PRINTING OFFICE

1906


2/138

Water-Supply

and Irrigat ion Papef N o . 1 8 0 Series M , General Hydrographic Inves t igat ions , 1 8

DEPARTMENT OF THE INTEEIOK

UNITED STATES GEOLOGICAL

SURVEY

CHARLES I). WALCOTT, DIRECTOR

TURBINE WATER-WHEEL

TESTS

AND

POWER

TABLES

BY

ROBERT

E HORTON

WASHINGTON

GOVERNMENT PRINTING OFFICE

1906


3/138

CONTENTS.

P a g e .

Introduction.............................................................. 7

Principal types

o f

water

wheels.............................................. 7

Ve r t i c a l water wheels.................................................. 8

Classes o f

turbines.....................................................

9

Tangential

outward f low turbines Barker's

mll......................

9

Radial

o u t w a r d - f l o w

turbines the

Fourneyron

turbine................. 9

Parallel d o w n w a r d - f l o w turbine the Jonval turbine................... 12

Radial

i n w a r d - f l o w

turbines the

Francis turbine...................... 13

Mi x e d - f l ow turbines................................................ 13

S c ro l l central-discharge wheels.................................. 14

A m e r i c a n type o f turbines...................................... 14

T y p e s

o f

turbine

gates

a n d

guides....................................... 16

M e c h a n i c a l

p r i n c i p l e s o f

the

turbine..........................................

17

H o r s e p o w e r

and

e f f i c i e n c y o f

turbines........................................

19

T u r b i n e

testing............................................................

2 2

G e n e r a l

review.......................................................

2 2

C e n t e n n i a l tests.......................................................

24

Tests by

James

E m e r s o n , and the H o l y o k e hydrodynamic experiments.......

30

Tests by

H o l y o k e

Water

P o w e r

Company................................

36

G e n e r a l discussion.................................................

36

Detailed tests..................................................... 41

M c C o r m i c k turbines...........................................

41

Hercules turbines..............................................

60

S a m s o n

turbines...............................................

66

N e w

A m e r i c a n and

S w a i n turbines............................... 71

T h e

u s e o f

the

turbine

as

a

water

meter......................................

7 6

Reliability

o f H o l y o k e

tests a s to turbine

discharge........................ 77

Variation in

d i s c h a r g e

f o r d i f f e r en t

w h e e l s

o f

s a m e

pattern.................. 7 8

Variation in d i s c h a r g e f o r d i f f e r e n t w h e e l s

o f

the s a m e type................. 7 9

Variation o f

turbine d i s c h a r g e

w i t h speed................................. 80

Variation

o f turbine c oe f f i c i e n t s w i t h variation in head..................... 81

M e t h o d s

o f

turbine setting

and

arrangement..................................

82

Turbine plants

f o r

varying

head............................................. 85

C o n d i t i o n s

g o v e r n i n g e c o n o m y i n

s ize

and number o f turbines used..............

85

Manufacturer's tables

o f

p o w e r , s p e e d , a r i d discharge...........................

87

G e n e r a l

discussion.....................................................

87

Rating

table

f o r

Fourneyron turbines................................

94

McElwain.................................................... 94

Rating

t ab les fo r sc ro l l c e n t r a l - d i s c h a r g e

turbines.

.....................

95

John Tyer................................................... 95

Reynolds..................................................... 95

C ar l ey helical................................................. 96

Perfection.................................................... 96

Jones Little Gant.............................................

97

3


4/138

4

CONTENTS.

Manufacturer's tables

o f

power, speed, and

discharge Continued.

P age .

General discussion Continued.

Rating

tables

for Jonval turbines....................................

9 8

McEwain.................................................... 9 8

Bloomingdale, or Wait's Champion..............................

9 8

Dx.........................................................

9 9

Osgood....................................................... 9 9

Bodine....................................................... 9 9

Chase........................................................ 1 00

Rating tables

for

register-gate

turbines............................... 1 01

Gates Curtis.................................................. 1 01

Eclipse

double................................................ 1 01

Helmcr's patent Rome......................................... 101

C a s e National................................................. 1 02

Wtmore..................................................... 1 02

Flenniken.................................................... 1 03

Humphrey

standard

IXL...................................... 1 03

Humphrey

standard XLCR.................................... 1 04

Burnham's

n e w improved......................................

1 04

Balanced

gate.................................................

1 05

Alcott's

high duty............................................ 1 05

Lesner's

improved.............................................

1 06

Risdon.......................................................

1 07

Rating

tables for pivot-gate

turbines.................................

1 08

Crocker......................................................

1 08

Camden horizontal............................................. 1 08

Camden vertical............................................... 1 09

Camden

steel

double ...........................................

1 09

United Sates................................................. 1 09

C o l e Domnion................................................

1 1 0

Badway.................................................... 1 1 0

Bartley water-tight............................................ Ill

Canada....................................................... Ill

Emer........................................................ 1 1 2

Eureka....................................................... 1 1 2

Smith

improved

Success....................................... 1 1 3

Smith

n e w

Success............................................. 1 1 4

American..................................................... 1 1 4

New

American................................................ 1 1 5

Poole

& Hunt

Letfel...........................................

1 1 6

Trump model.............---.-...--..----..-....-..-.........

1 1 7

Leffel........................................................ 1 1 7

Le f fe l

Samson................................................. 1 1 9

Rating

tables for

cylinder-gate

turbines...............................

1 1 9

Rochester.....................................................

1 1 9

Swain........................................................

1 2 0

Dolan's Little

Gant............................................ 1 2 0

Dolan's

Improved

Little

Gant..................................

1 2 1

Hunt Standard, n e w pattern.................................... 1 2 2

Hercules...................................................... 1 2 2

McCormck..'................................................ 1 2 3

McCormick's New England...................................... 1 2 3

Taylor sleeve-gate.............................................

1 2 4

Vctor........................................................

1 2 4

Victor

high-pressure............................................ 1 2 5


5/138

CONTENTS.

5

P a g e .

Lterature................................................................ 1 2 6

Hstorical.............................................................

1 2 6

Descriptive........................................................... 1 2 6

Ve r t i c a l water

wheels...................................................

127

Turbines.............................................................

1 27

T u r b i n e design....................................................

1 27

A m e r i c a n type o f

turbine...........................................

12 8

Mathematical

theory o f turbines..................................... 12 8

Turbine governing................................................. 1 29

I m p u l s e

water wheels.................................................. 1 30

Index................................................................... 131


6/138

I L L U S T R A T I O N S .

PLATE I.

A,

Recent American

type o f

water-wheel runner; B, Dynamometer,

Hoi-

yoke testing

flume..............................................

1 4

II.

A,

Turbines o n horizontal shaft; B, Pair o f

turbines

o n

horizontal shaft.

8 2

FIG.

1. Section

o f

Fourneyron

turbine........................................

1 0

2 .

Plan

o f

Fourneyron

turbine..........................................

1 0

3 . Double Fourneyron

turbine at

Niagara Falls........................... 11

4 . Section

o f

guides and buckets,

Niagara Fourneyron

turbine.............. 1 2

5.

Section o f

Francis center-vent turbine.................................. 1 3

6 .

Section

o f

runner

o f

Francis

center-vent

turbine........................ 1 3

7 . S c h i e l e

turbine.....................................................

1 4

8 . C r o s s

section

o f early turbine with

deep

bulging buckets, pivot gates, and

an adjustable step bearing...............

......_... _...............

1 4

9 . Diagram illustrating principle

o f reaction.............................. 1 7

10.

Diagram showing impulse against curved vanes......................... 1 8

11.

Diagram

illustrating theory

o f

moving

vanes...........................

1 8

12.

Diagram

showing

interference

and eddies in a

turbine...................

2 2

13.

Diagram showing e f f i c i e n c y o f

various

prime movers.................... 2 3

14. C r o s s

section

o f

Holyoke

testing

flume.................................

3 7

15.

Log

o f test o f 3 6 - i n c h Hercules turbine, fu l l gate........................ 3 8

16. Log o f test

o f

36-inch

Hercules turbine,

0.806

gate......................

3 9

17.

Log o f

test o f 3 6 - m o h

Hercules

turbine, 0 . 6 4 7 gate......................

3 9

18.

Log

o f test o f 36-inch Hercules

turbine,

0.488 gate...................... 4 0

19. Log

o f test o f

36-inch

Hercules

turbine, 0 . 3 7 9

gate......................

'

4 0

20.

Proportional discharge

c o e f f i c i e n t s ,

12- , 15- , 18- , and

21-inch

M c C o r m i c k tur

bines.

...........................................................

4 1

21.

Proportional discharge c o e f f i c i e n t s , 2 4 - , 2 7 - , 3 0 - ,

and

33-inch M c C o r m i c k tur

bines. ........................................................... 4 2

22. Proportional discharge coefficients, 3 6 - , 3 8 - , 42-,

and

45-inch M c C o r m i c k tur

bines. ...........................................................

4 2

23 . Proportional discharge coefficients,

4 8 - ,

51- , 54- , and

57-inch

McCormick tur

bines.

........................................................... 4 2

24 . Proportional discharge

coefficients,

Hercules

turbines.................... 6 0

25. Proportional discharge c o e f f i c i e n t s , Leffel-Samson turbines.... .. . ......... 6 6

26. Efficiency

curves,

Lefl'el-Samson

turbines..............................

6 7

27 .

Proportional

discharge

coefficients,

N e w

American

turbines.........'......

7 1

28 . Part-gate discharge c o e f f i c i e n t s for three 24-inch Hercules turbines........ 7 8

29. Types o f part-gate discharge

coefficient curves..........................

7 9

30. Variation o f turbine discharge with

speed,

24-inch M c C o r m i c k turbine....... 81

31.

Variation

o f

turbine

discharge with speed, 42-inch M c C o r m i c k turbine..... 8 2

32. Variation o f turbine discharge

with speed, 54-inch

McCormick turbine..... 8 3

33.

C r o s s section o f

power house

near

Geneva,

Switzerland

..................

8 4

6


7/138


8/138

8 TCTEBINE WATEE-WHEEL TESTS AND POWEE

TABLES.

and

the rouet

volante,

w e r e placed o n vertical shafts. The classification by position of

shaft thus served very

we l l

to

distinguish

between water

w h e e l s

and turbines

until tur

bines

were placed o n horizontal shafts. The rouet volante o r flutter wheel

o f the

ancients

consisted o f flat, vertical

vanes

projecting radially

from

a vertical wooden shaft. The

water

jet

from the

feeding spout struck the vanes tangentially near their

ends.

Such

w h e e l s have

been

used

for

centuries in

India,

Egypt, Syria, and southern France. An

excellent example o f a rouet

volante

was

in

use

until

recently

in a plaster mill in western

New York. The

rouet

volante

placed o n a horizontal shaft becomes

essentially the hurdy-

gurdy

o f the early western miners. It

may

thus be considered a s the prototype o f the

modern

impulse

water

w h e e l a s

wel l

a s o f

the

turbine.

M u c h uncertainty o f meaning has arisen from the conflicting u s e o f terms in

classify

ing water w h e e l s . The terms impulse and

reaction,

for example, have been used

by dif

ferent authors

with

opposite meanings.

The

conception

o f

reaction

i s somewhat

difficult

to grasp,

and

a s the definition o f

this

word s e e m s

uncertain

its u s e is to be discouraged.

Its

usual

meaning

wi l l

be

explained, however,

in the

course

o f

this

paper,

in order

that

its

u s e

in

works

o f

reference

may

be

understood.

VERTICAL, \VATERWHEELS

The

overshot

w h e e l i s

a

characteristic type,

although it

is

probably

antedated

historic

ally

by

the

bamboo varia,

which w a s

used by the Chinese,

a s they

claim,

a s

early

as

1 0 0 0

B . C.

A form

o f inverted

chain pump has been used in the Orient from time imme

morial for lifting

water from streams to

irrigation ditches. A

motor

o f

this type

has

recently been patented in America, and o n e is in operation in

Mannsville,

N . Y.,

under

a

head

o f

2 3 feet, yielding abundant power to drive a

grist

and planing mill. Such wheels,

a s

wel l a s

overshot

w h e e l s ,

operate

purely

by

gravity,

and yield theoretically

a

very high

e f f i c i e n c y . The objections to this type o f motor are cumbersomeness, waste o f water by

leakage and spilling

from the

buckets,

inability

to

operate

in backwater,

and obstruction

by i c e in

winter.

Overshot w h e e l s w e r e formerly built

o f great

s ize . O n e at Laxey,

Isle

o f Man, con

structed about

forty years a g o and said

to

be still

in

operation, is 7 2

feet G

inches

in

diam

eter and

develops

about 150

horsepower.o

A number

o f

overshot wheels

are

in u s e at

old mills in

the

Catskill

Mountains

in New York. A firm in

Pennsylvania manufactures

"steel overshot"

water

w h e e l s , which,

it

is

claimed, have

a

high

e f f i c i e n c y .

Breast w h e e l s

a r e

operated

partly

by

gravity

and partly by kinetic energy, the water

from

the

feeding

chutes striking

the floats

or

vanes

o f

the

w h e e l .

Undershot

water w h e e l s

and current wheels operate entirely by the kinetic

energy o f

the moving water.

Tide w h e e l s

and

undershot w h e e l s

usually require

a

floating

framework or other device

to

raise

and lower them with fluctuation in

water

l e v e l .

Breast and undershot w h e e l s never attain high e f f i c i e n c y , and in addition are subject

to

al l

the

objections

o f

the

overshot

water w h e e l . The

labors o f James

Smeaton,

Fair-

barn, and

the

ingenious Poncclet, w h o substituted epicycloidal-curved vanes for straight

buckets in w h e e l s

o f

these types, increased their e f f i c i e n c y somewhat, but such wheels

w e r e

quickly superseded

by

the parallel-flow

turbine o f Jonval and

the

Boyden-Fourneyron

turbines

upon

their introduction into this countiy.

Vertical water

wheels

are

still

con

siderably

used in Germany.

The

theory

o f

water

wheels

has

been

elaborately developed and their literature

is

much

more profuse than that o f turbines, b

a

Se e catologue

o f the Pelton Water W h e e l

Company

for 1898, pp. 70-71.

6 See bibliography o n p a g e s

126-130.


9/138

PRINCIPAL

TYPES

O F

WATER WHEELS. 9

CLASSES

OF

TURBINES.

A turbine a may

be d e f i n e d as

a water w h e e l

in

w h i c h t h e water

is

admitted to all the v a n e s

o r buck e t s s i m u l t a n e o u s l y .

It

is thus

d i s t i n g u i s h e d f r o m vertical

water w h e e l s ,

w h i c h

r e c e i v e

the

water

at the

top

o r

o n e

s i d e o n l y , a n d f ro m i m p u l s e water w h e e l s , w h i c h r e c e i v e a

spout

i n g

jet

o r

jets

f r o m

n ozz l e s

directed

tangentially

a g a i n s t

the perimeter

o f

the

w h e e l .

The

component parts o f

a

turbine a r e the

"runner,"

the "case," the "gate" o r "gates,"

and

the "guides." Commonly the

gates and

guides are included in the "case." The

runner

is

that portion o f the turbine

which revolves.

It

comprises

the vanes,

the crown

plate, parti

tion

plates o r rim

bands, which cover, subdivide, or

strengthen the vanes, and the

power

shaft. The term '' bucket" i s applied to the passage for the water in the runner. The vanes

or floats are

the partitions

separating the

buckets and

forming

the runner.

The

term

"buckets"

i s a l s o often used to signify

the

vanes.

The chutes are the

openings

through

w h i c h the

water

passes into

the

w h e e l ,

and

the guides are the partitions separating

the chutes

The gates

serve

to shut o f f and regulate

the supply.

The

f l o w

o f

water through a turbine

may

be directed either radially inward or outward o r

parallel to

the

axis, or

inward

and parallel, or inward, parallel,

and outward.

The repre

sentative typos o f these several c l a s s e s are a s f o l l o w s :

Tangential f l ow:

Barker's

mil l .

Parallel

f l ow: Jonval

turbine.

Radial outward

f l ow: Fourneyron turbine.

Radial inward

f l ow: Thompson vortex

turbine;

Francis turbine.

Inward and

downward

f l ow:

Central discharge

s c r o l l

w h e e l s

and earlier American type

o f

wheels; Swain turbine.

Inward, downward, and outward f l ow: The American

type o f

turbine.

TANGENTIAL

O U T WA R D - F LO W TURBINES BARKER S MILL.

In

i m pu l s e water w he e l s the jet

s t r ikes

o r

enters

t h e

buck e t s

in a d i r e c t i o n tangential

to

t h e c i r c u m f e r e n c e

o f

t h e

runner. In

m o s t f o r m s

o f

turbines the water

f lows

outward,

inward

o r

d o w n w a r d

t h r o u g h

t h e

b u c ke t s ,

l e a v i n g them

tangentially o r

nearly so .

The

simplest

type o f

tangential

outflow

i s

Barker's

mill, invented in 1740. This w h e e l has

radial

arms and operates purely

by

reaction. Such w h e e l s are still used o n the Morris Canal

in

New Jersey

for drawing

barges

up the

inclined planes

which

serve

in

place

o f

l ocks .

The

w h e e l s have four arms o f 6 feet radius, with

openings

at the ends 3 ^

inches

wide by 15J

inches

h i g h . f r

James

Whitelaw,

o f

Paisley,

developed Barker's

mill,

which

has

spiral tapering

arms

so

curved that water f l o w s radially when the mill

i s

running at proper speed. A w h e e l

o f

this

type

erected

o n

Chard Canal,

1 8 4 2 ,

for purposes

o f hauling

boats

up

inclines developed 7 5

per cent e f f i c i e n c y o n 2 5 feet fa l l . Owing to their large s ize ,

l o w speed,

and inability to

operate in backwater such w h e e l s

have

never c o m e into extensive u s e .

RADIAL OUTWARD-FLOW TURBINES THE FOURNEYRON TURBINE.

A

p r i m i t i v e

type

o f

water

w h e e l , w h i c h c o m e s

under

t h e c la ss o f

turbines

proper is

that

o f

C a d i a t . T h i s is a n o u t w a r d - d i s c h a r g e turbine without g u i d e chutes,

and

t h e r e f o r e it may be

s a i d to

b e l o n g

to t h e

s a m e

s t a g e

in

turbine

evolution

a s d o

t h e

tub

and

s c ro l l

central-dis

c h a r g e w h e e l s , although the

f o r m

o f

runner

and

t h e

d i r e c t i o n o f

f low a r e s imi l a r to

t h o s e

o f

t h e

Fourneyron

turbine. T h e w e i g h t

o f

the runner is

c a r r i e d

by a

step-bearing

at the l o w er

e n d

o f t h e

s h a f t . T h e

d i s c h a r g e

is

r e g u l a t e d

by

a n o u t s i d e cylinder gate, probably the f i rs t

o n e u s e d . T h e

buckets

a r e c u r v e d i n a v e r t i c a l

p l a n e .

F ig .

1

s h o w s a sketch in

s e c t i o n

o f a n e a r l y Fourneyron turbine (after Mo r i n ) .

T h e

g u i d e

chamber

C r e c e i v e d t h e vertical p r e s s u r e

o f water, and

w a s

s u s p e n d e d

f r o m a b o v e by m e a n s

a From Latin

turbo,

to

revolve. The etymology

of the

word

does

not sufficiently distinguish

tho

class.

6

W i l s o n , H . M.,

T h e

Mo r r is C an a l

a n d

i t s i nc l i ne d

p lanes : Scient i f i c

A m e r i c a n

S u p p l e m e n t ,

F e b r u a r y

2 4 , 1 8 8 3


10/138

1 0

T U R B I N E

W A T E R - W H E E L

T E S T S A H D P O W E R T A B L E S .

o f a h o l l o w

c o l u m n surrounding

the

d r i v i n g

shaft. T h e d i sc h a r g e w as

regulated

by a cy l i n

d e r gate

G b e t w e e n

the g u i d e C and the bucket

F.

Sl i t s in the gate

r i n g 6

o p p o s i t e the

e n d o f

e a c h g u i d e e n a b l e d

the

g u i d e s

to

be extended outward

nearly to the

v a n e s .

Fig . 2

s h o w s a p l a n

o f

the g u i d e chamber

and

runner

o f

this turbine. T h e v a n e s o r

buck e t s h a v e

a radial d i r e c t i o n at their

inner

e n d s , w h e r e

they

r e c e i v e the wa t e r .

Under

the

m e c h a n i c a l c o n d i t i o n s e s t a b l i s h e d

the

water

enters

the w h e e l

with

a tangential v e l o c i t y

PIG. 1. Section o f

the Pourneyron

turbine.

e q u a l t o the

v e l o c i t y

o f

the

bucket,

is

c a r r i e d

outward by

the

radial c o m p o n e n t o f its v e l o c i t y ,

and

in p a s s i n g

outward

is

d e f l e c t e d by the backward-curved v a n e s o r buckets, thus d o i n g

work. Inasmuch a s

the

tangential

c o m p o n e n t o f the v e l o c i t y e q u a l s

that

o f the

buckets

the

water

c o u l d

d o n o

w o r k

by

i m p u l s e , h e n c e

the

Fourneyron

turbine

is

purely

a

p r e s s u r e

o r

reaction turbine.

FIG. 2. Plan o f

the Fourneyron turbine.

T h e e x c e l l e n c e

o f

its m e c h a n i c a l

construction,

its h i g h e f f i c i e n c y ,

its

ability

to

w o r k under

very great h e a d s ,

a n d

its ability

to operate in backwater

with g o o d e f f i c i e n c y

r e n d e r e d

the

appearance

o f

the

Fourneyron turbine a

notable

e v e n t in

the

history o f

water p ow e r .

T h e

experiments o f M. Fourneyron w e re b e g u n

in

1823 ,

a n d h i s

f i rs t turbine w a s

e r e c t e d

at Pont

sur 1 ' O g n o n , France,

in 1827. It

w a s f o l l o w e d

by

s e v e r a l o t h e r s , operating under

various

h e a d s

up

to

144

fee t ,

w h i c h

y i e l d e d

ef f i c i enc i es a s

h i g h

a s 80

per

c e n t .


11/138

CLASSES OF TURBINES.

11

In 1 8 3 7 M .

Fourneyron

erected

a

turbine at

St.

Blaise, Switzerland, which

operated under

a head o f 3 5 4

feet. The

diameter

o f

the

w h e e l w a s 1 3 inches. The depth

o f

the buckets w a s

slightly

l e s s than one-fourth o f an inch. This w h e e l made from 2 , 2 0 0 to 2 , 3 0 0

revolutions

per minute, and

is

reported to

have

yielded

an

e f f i c i e n c y

o f 8 0

to 8 5 per cent. The water

w a s

conducted

to

the

turbine through

a cast-iron

pipe

conduit, and

to

prevent

the

chok

ing o f

the

minute apertures in

the

water w h e e l

the supply

was filtered before u s e .

January

1 , 1 8 4 3 , a Fourneyron turbine,

designed

by Elwood

Morris,

w h o had translated

the valuable experiments o f M o r i n

into

English, was erected at Rockland Cotton

Mil l s ,

o n

the

Brandywine. This turbine w a s

tested by

M o r r i s in

the

fall o f

1 8 4 3 , together

with a second

one,

located at Dupont Powder Mill , a l s o o n

the

Brandywine, near Wilmington, Del .

These

turbines gave maximum

e f f i c i e n c i e s

o f 7 0 to 7 5 per

cent,

respectively.

In

1 8 4 4

a Fourneyron

turbine, constructed by Uriah

A. Boyden,

was erected at

the

Apple-

ton

Company's

cotton mills in

Lowell

M a s s . Carefully conducted tests showed that this

turbine yielded an e f f i c i e n c y

o f

7 8 per

cent.

The

Appleton

turbine

w a s

rap

idly f o l l o w e d by others o f

Boy

den's

design, which s o o n became

the

stand

ard

in New

England, displacing the

o l d

wooden vertical w h e e l s .

The

Boyden

turbines w e r e expensive,

cumbersome,

and

gave l o w

e f f i c i e n c y

when

operated

at part gate,

and "owing

to the large

number

o f

buckets

with small apertures

they w e r e liable to b e c o m e

choked

by

chips, leaves,

and other

floating

obstruc

tions,

not to

speak

of f i s h .

At Fall

River, Mass.

the

first

turbines

are

said

to have been

stopped by e e l s

on their

annual migrations to the sea . "a

The

manufacture o f Fourneyron tur

bines w a s

taken up by a

number o f ma

chine works,

and

several

o f the Boyden

turbines are still in

u s e

in New England.

A s usually constructed

this turbine has

a

cast-iron casing

attached

to

o n e s i d e

o f

the

flume, similar to the s c r o l l central-

discharge

w h e e l .

FIG. 3. Section o f

penstock and

runners o f double

Fourneyron

turbine

at Niagara Falls. A, Flume;

B, penstock; CC, runners; DD, guides; EE, buckets;

FF,

gate rings; HH, holes in

upper

drum; //, holes

in lower runner; . 7 " , gate stems.

The

ability o f a turbine

o f

the

Four

neyron type to work efficiently under

very

high heads was shown

by the experi

ments made at

St.

Blaise.

The

manu

facture

o f turbines

o f the Fourneyron type has been revived in recent

years,

owing

to the

demand for

turbines to operate under

very high heads, as at

Niagara Falls and

elsewhere.

Figure 3 shows a schematic c r o s s section

o f

the

double

Fourneyron

turbine

used in the

first

installation

o f

the Niagara Falls

Power Company. This

was

operated under a

head

o f

about 1 3 5 feet.

The turbine i s

mounted

in

a g l o b e

penstock,

similar to that

used in

early

New England practice, with the exception that

two

w h e e l s are used, o n e being placed at the

top

and the

other at

the bottom o f

the penstock.

A s

shown in fig.

3 the runner

C

and

buckets

E,

which

are represented

in black,

are attached to the vertical

shaft. The

guides D

and

buckets E

are

subdivided

into three

compartments

by partition plates. The discharge

is

regulated by

outside cylinder

gates F.

The gate rings for

the upper and

lower wheels are

connected by rods, o n e o f

which i s shown

at J.

The

gate rings F are raised and lowered in

unison to shut o f f the outflow from or to open, o n e

after

another, the

horizontal compart

ments,

as required. The cylindrical penstock is shown in

section

by hachure. The disk or

" W e b be r ,

T h e D e v e l o p m e n t

o f

W a t e r P o w e r .


12/138

Bucket

ring

32

buckets

Guide ring

6 chutes

12

TURBINE

WATER-WHEEL

TESTS

AND

POWER

TABLES.

drum forming

the

lower end o f

the

penstock

i s made solid,

and h o l e s II are provided in the

lower

runner

to a l l o w any water which may enter between

the

lower drum G

and

the l o w e r

runner through

the

clearance

spaces

to pass

out. Holes

HH are provided in

the

upper

pen

stock drum to a l l o w water under full pressure o f the head to pass through and act vertically

against the

upper

runner

C.

In

this

way

the vertical

pressure

o f

the

great

column

o f

water

i s

neutralized and a means

i s

provided to counterbalance

the weight

o f the

long

vertical

shaft and

the

armature o f

the

dynamo at its upper

end. These

turbines discharge 4 3 0

second-feet,

make 2.50 revolutions per

minute, and a r e

rated

at 5 , 000

horsepower.

A section

o f

o n e

o f

the

guide

rings and runners

i s shown

in

f ig .

4. The

guides

and buckets

a r e o f

bronze, and

their

surface curves

form

arcs o f circles

o f

varying

radii.

Except

for the central

thickening

o f the

vanes, the

forms

o f the chutes and buckets

d o

not

differ

materially

from

those

o f

the same parts o f

the

early turbines o f

Boyden and

Fourneyron.

A

Fourneyron

turbine

similar

to

that

at Niagara Falls

has

been

erected at

Trenton

Falls, N . Y .

This turbine

operates

under 2 6 5

feet g r o s s

head

and has 3 7

Fin. 4. Section o f

g u ide s

a n d b u c k e t s ,

F o u r n e y r o n t u r b i n e , buckets,

each

5

inches deep

N i a g a r a Falls.

and

^ ; }

inch

w i d e

at

the least

section.

The total area o f oat-

f l ow at

the

minimum section i s , therefore,

1 6 5

square inches. How enough water can

pass

through

so small

an aggregate aperture to

yield

continuously 9.50 horsepower

i s

a

matter for legitimate wonder.

PARALLEL DOWNWARD-FLOW TURBINE THE JONVAL TURBINE,

The idea o f a parallel-flow t u r b ine ,

is said

to

have originated

with

Euler.

M .

Fontaine put

it

into form

for

practical

u s e ,

and M. Jonval

added

the draft tube from which

it bears

his

name.

In

1 S 3 7

O .

Henschel,

of Oas s e l ,

invented the

downward

parallel-flow

turbine, later

known

bv the

name o f

Jonval

or Koechlin.

T h e

Jonval

turbine closely resembles a later type

o f

flutter

w h e e l known a s

the Borda turbine,

which

has inclined

floats and receives water

from

a

spout directed downward. The

outer ends o f the vanes

are inclosed

in

a

circular

curb.

Thus a runner

o f

the

Jonval

type w a s derived

by

easy

transitions

from the

primitive

flutter w h e e l .

This

w h e e l

receives water

at

only o n e

point

o n

its circumference.

In

the

Jonval w h e e l the spout

i s

replaced by

a

ring o f

guide

chutes, which admit water a l l around

instead

o f

at o n e point. The Jonval w h e e l became

at

once

the

competitor o f

the

Fourney

ron turbine. The

Jonval turbine w a s

introduced

into

America by Elwood Morris and

Emile

Geyelin, o f

Philadelphia,

about the

middle o f the nineteenth century.

The

tub

w h e e l w a s

a

parallel-flow

turbine

without

guides.

This

w a s

placed

in

the bottom

o f

a f l u m e

and commonly contained

a

number o f inclined

or curved vanes,

the

runner

being

similar to that o f the Borda

turbine

in its earlier and to the

Jonval

turbine in its

later

form.

Sometimes

but o n e o r two vanes were used, forming a helix o r s c r e w w h e e l . The tub w h e e l ,

when fitted with a

cover

containing guide

passages

to direct the currents

o f

water against

vanes, becomes essentially a

Jonval

turbine.

The

tub w h e e l w a s in common use in America

at the

time

the Jonval turbine

w a s

introduced.

The theory o f the design o f the Jonval turbine

forms

a neat problem in

applied

mathemat

i c s , and

i s extensively

discussed by

various

writers.^

"

S e e

bibliography,

pp.

120-130.


13/138

CLASSES OF T U B B H S T E S .

13

A variation

o f

the Jonval turbine, in

which

the number o f buckets w a s

reduced

to two,

was

extensively

used

in

sawmills in

northern

New York. Owing to

the

large openings o f the

buckets, i c e ,

drift,

and

other

obstructions could pass through this

w h e e l

without injuring

it.

The

vanes were nearly horizontal, giving a high

speed

o f

rotation.

The e f f i c i e n c y w a s

very

l o w .

In

the Jonval turbine the velocity o f water

at

the outer ends

o f

the buckets

i s

greater than

that at the inner ends. In order to increase

the capacity

o f the w h e e l without the l o s s o f

power

that

would result from unequal velocities in

the

outer

and

inner portions o f a

broad

FIG. 5. Section

o f

Francis

center-vent

turbine at Booth

Cotton Mi l l s , 1849.

C,

Guide

chutes:

D,

run

ner; < ? , inside cylinder gate ring;

H,

holes

through

runner disk to

admit water and neutralize

pres

sure:

.R,

gate stems.

bucket

annulus,

the

Geyelin Double

Jonval turbine

has

been devised.

This

contains

two

rings o f

buckets,

o n e

within

the other, the

inclinations

o f

the

buckets differing, so

that the

angular velocity o f both

rings

i s

the same;

the intention being to secure a turbine o f large

capacity

in small compass.

Jonval

turbines are still

manufactured by

a number o f American firms, and

rating tables

are

given

o n pages

98-100.

RADIAL INWARD-FLOW TURBINES THE FRANCIS TURBINE.

James B .

Francis,

w h o was

intimately

associated witli Uriah

A .

Boyden in testing

early

American Fourneyron turbines, experimented

in

1 8 4 7 o n a

model o f

a

center-vent

turbine

which was

essentially

a

Fourney

ron turbine having the relative

positions

o f the

guides

and buckets

and

the direction

o f f l o w re versed,

a

Such a w h e e l

had

been proposed

by

Poncelet

in 1826. A patent

w a s issued to

Samuel

B . Howd,

o f Geneva,

N.

Y.,

in 1 8 3 6 for an

inward-flow turbine, s o m e features

o f which w e r e embodied in t h e .

Guide chutes

FIG.

6. Section

o f runner o f

Francis center-vent

turbine.

Francis turbine.

The

inward-flow

turbine

was

destined to

supplant

a l l others,

but it

w a s soon found best

to

extend

the buckets downward,

thus

making an inward

and

downward f l o w turbine.

MIXED-FLOW

TURBINES.

This

c l a s s

includes (A) scroll

central-discharge w h e e l s , embracing

(1)

turbines without

guides,

(2) the Burdin turbines, (3) Thompson

vortex

turbine; (B) early American types

o f turbines

having

double-curved

buckets

extended downward b e l o w the guide ring, but not

protruding outward.

In these w h e e l s

the runner can

be

lifted

vertically

out o f the

c a s e .

o Francis, J.

B v

Lowell Hydraulic

Experiments, pp.

55-60.


14/138

1 4

TURBINE

WATER-WHEEL

TESTS AND

POWER TABLES.

FIG.

7. Schiele

turbine.

SCROLL

CENTRAL-DISCHARGE WHEELS.

S c r o l l - c a s e

turbines have flat

vanes, or

vanes

that are curved

but little

from a

vertical

plane.

The action

o f the

water is chiefly

radially inward, although the

discharge is

both

upward and

downward.

The

best developed

turbine

o f

the

s c r o l l

central-discharge type

is

the

Schiele

which

has

curved guide

vanes

and

buckets,

the latter

attached

to periphery

o f a

central

drum.

( S e e

f ig.

7.) The discharge is controlled by a gate

in the chute.

The Thompson

vortex turbine and certain

American types

o f bulging-bucket

turbines

mounted

in

scroll cases

also'discharge

both

up

ward and downward. Many scroll central-dis

charge turbines,

with

no guide passages

and with

the controlling gate

in

the throat o f the s c r o l l

case, are still in use.

The

gate

is

either

o f

the

sliding or

o f the pivoted butterfly

type. Some

forms o f

this

w h e e l

have rudimentary guide

pas

sages,

two in

number,

opening on

opposite

sides

o f

the

runner, their object being to

distribute the

water

equally

around the periphery

o f

the wheel, and to prevent

a

portion o f the runner

from "running

dry.'

AMERICAN TYPE

OF

TURBINES.

The

earliest step toward

the

development o f

the turbine in America is a

patent

issued to

Benjamin

Tyler,

o f

Lebanon,

N.

H.,

in

1 8 0 4 ,

signed

by

Thomas

Jefferson,for

an

"improve

ment in watei

wheels."

Apparently the

water wheel

improved

i s

a

primitive flutter w h e e l

or

rouet volante, and

the

improvement consisted in hoop

ing

the

w h e e l with iron hoops

and setting the wooden

vanes at a

specified

angle.

Credit for

the

s c r o l l c a s e i s assigned by W. W. Tyler

to

the Parker brothers, o f

Licking

County,

Ohio, the

American

patentees o f the

draft tube

in the early half

o f

last

century.a

From 1 850

to

1 8 7 5 many turbines

w e r e

built nearly

o n

the

lines

o f

the

Howd-Francis

turbine, but with

buckets curved downward to an increasing extent in

successive forms.

Tests

o f

the

Swain wheel in

the

six

ties proved conclusively

the

merit o f this type.

In

the

same decade the pivot o r wicket gate a s successfully

applied

in the "American"

and

"Leffel"

turbines,

and

thus a step in advance was taken toward improvement o f the part-gate

e f f i c i e n c y

o f

turbines. LefTel a l s o introduced

the

short

draft

tube, carrying the bridge tree

and step

bearing,

giving

the

turbine

c a s e practically

the

form at

present retained.

The Risdon

turbine having an inside cylinder gate and buckets slightly curved downward led in

e f f i c i e n c y

at

the tests

made

at

the Centennial

Exposition

o f

1 87 6.

At

this

exposition

much attention w a s a l s o

attracted

by tests

o f

the Little Giant turbine, manufactured by

Knowlton

& Dolan,

o f

Indianapolis,

under

a patent issued to Matthew

and John

Oben-

chain.

This w h e e l has

ladle-shaped bulging buckets, and similar

w h e e l s were

soon

devised

by John

B .

M c C o r m i c k , from w h o s e

designs

the

Hercules,

Hunt,

Victor, and several makes

o f ''McCormick" turbines have

been developed.

In figure

8 the arrows indicate the inward and

downward

direction

o f

f l o w

o f

the

water.

Provision is made

for

a slight outward f low. In

turbines

o f this type, a s

we l l

a s in

those

FIG. 8. Cross

section

of an early

turbine with deep, bulging buck

ets,

pivot

gates,

and

an

adjustable

bearing (B).

a

Tyler,

W.

W.,

Evolution o f the

American Type

o f Water Wheel.


15/138

U.

S.

GEOLOGICAL SURVEY

WATER-SUPPLY

PAPER NO. 180

PL. I

A.

RECENT AMERICAN TYPE OF WATER-WHEEL RUNNER.

B.

DYNAMOMETER, HOLYOKE TESTING FLUME.


16/138

CLASSES OF TUEBINES. 15

with

inward

and downward

f l o w only, the

buckets

are

commonly

made

o f

wrought iron

or

steel secured

in a

cast-iron head,

a s

here shown, and strengthened by

a

band at C .

C l e m e n s Herschel writes:a

American

turbines

are

mostly o f a

complex

nature, as regards the action o f the water

on

the buckets

o f the wheels, and

have

been perfected in efficiencyby test, or,as it is irreverently called, by the " cut and

try "

method

o f procedure. A wheel would be built on the inspiration o f the inventor,

then

tested in

a

testing flume,

changed

in

a certain part,

and retested, until no further

change

in that

particular could

ef f ec t

an improvement.

Another part

would

then

undergo the same process o f reaching perfection,

and

thus in course o f t i m ' e the whole wheel would

be brought

up to

the

desired high standard o f e f f l c i e n c y .

The

American type o f turbine

i s

distinguished by the great depth

o f

its buckets, its great

capacity in proportion to

its

diameter,

and

by

its

high speed. It

i s

a l s o distinguished

by

the

form o f its

buckets,

which

consist

o f a

ring

o f

curved vanes

arranged parallel to

the

axis and

inclosed within

the guide

ring.

Below

the

guide ring

the

buckets expand down

ward and

outward, forming large

cup-shaped outlets.

The evolution

o f turbines having enormous capacity compared with their

s i ze i s

largely

the

result

o f

the

desire for

great

power

in

a small

and consequently

cheap

wheel,

and

the

desire

to

procure as high a speed a s possible. The speed o f a w h e e l under a given head

varies

inversely a s its

diameter.

T o increase the capacity o f

a

turbine without increasing

its diameter requires an increase in its depth. Thus w h e e l s with

very

deep buckets have

been evolved. This

i s illustrated

in

PI .

I,

A,

showing

the inlet end

o f

the runner

o f a deep-

bucket

w h e e l .

When a w h e e l

i s

operating under l o w

heads

the lower part

o f

a deep bucket i s operating

under

an

appreciably greater

head

than the upper

part;

hence to maintain a proper velocity

o f

the

water

passing

through

the turbine,

and to enable it to

leave

the runner with a l o w

velocity, large

bucket

outlets

are

required. These could

not

be obtained in

the narrow

compass

o f a

runner

o f

small

diameter, and to remedy this

defect large

cup-shaped buckets

protruding

downward and

outward

from

the

inlet chutes were devised. The

course

o f

the

water

in passing through

these

complex

buckets

is

first radially inward, then axially

down

ward, then tangential, o r

outward

o r both, thus

effecting

a nearly

or

quite

perfect

rever

s i o n o f current direction. The large ladle-shaped vents perform

another

important func

tion in

that

they

distribute

the water uniformly within the draft tube.

Recent improvements in

this

form

o f

w h e e l have been (1)

the

arranging o f w h e e l s in

pairs o n horizontal

shafts,

made possible

by the use

o f

the draft tube;

(2)

the

invention o f a

governor that wil l control

the

speed

o f the

w h e e l

with a

degree o f uniformity

that

is

com

parable with that effected by the best engine regulators; (3)

the

development o f such a

relation

between

the gate

mechanism

and

the runner

design as

to

give a

high

e f f i c i e n c y

with

a considerable range o f gate

opening.

American turbine practice differs from

European

practice in that

water

wheels are

placed

on

the market in

standard or stock

s izes , whereas

in

Europe, notably o n the Continent,

each turbine i s designed for

the

special conditions under

which it

i s to operate, the designs

being

based

on mathematical

theory and

following chiefly the Jonval and

Fourneyron types.

Thirty

years

ago there w e r e probably

more

establishments engaged in the

manufacture

o f

turbines than there are to-day. The

keen

competition o f that time led to the development

o f better turbines,

and the

relatively small

number

o f firms

having

the

ingenuity

and the

facilities to

meet

the demand are the o n e s that have survived. At the

present

time a large

majority

o f

the turbines

used

in

this country

are

built

in

half

a dozen

factories.

Having

been developed

by

experiment

after

successive

Holyoke tests

(described o n

pp.

36-37), American

stock

pattern turbines probably

give

their best


at about the

head

under which those

tests

are

made i.

e., 14 to 1 7 feet. The shafts, runners, and cases

are so

constructed a s

to

enable

stock s izes

o f

wheels to be

used

under

heads

ranging

from

6

to 6 0 feet. For very

l o w

heads they are

perhaps

unnecessarily cumbersome. For heads

exceeding 6 0 feet American

builders

commonly resort to the use o f bronze buckets and

"special

wheels,"

not designed along theoretical

lines, a s in Europe,

but

representing modi

fications o f the standard patterns.

oCassier's

Magazine,

Niagara

power

number, July,

1895,

p.

243.


17/138

16 TURBINE

WATER-WHEEL

TESTS AND

POWER

TABLES.

TYPES OF TURBINE GATES AND GUIDES.

Practice as

to chutes

or guides differs widely. They are

usually

fewer in number than

the

buckets.

The cogent dogma

o f

water-wheel

design

i s that

the

water

should

enter without

shock

and

leave

without

velocity. This implies

that the direction

o f

motion

o f

water

on

leaving the buckets

shall

be

opposite

to that o f the buckets

themselves,

and that its velocity

relative to the buckets shall

be

equal to that o f the buckets. The water wi l l then have no

velocity

relative

to

the earth.

This law requires that

the

water shall

enter the

buckets at

an angle at

which

it wil l

glide smoothly

in

without

shock.

The

guide

passages are made

as

f e w in number a s is reasonably

consistent

with this dictum.

The

constmction

o f

turbines

without guides has

a l s o

its advocates.a

With regard both to

the

e f f i c i e n c y and

the

general

merit

of

the wheel, the gates are per

haps

the

most important feature. Among the different

types o f

gates are outside register

gates,

inside register gates, inside cylinder

gates,

wicket o r

pivot

gates.

Register gates may

be

o f the plate o r o f

the

ring type, according

as

they are applied to

parallel-flow or

inward-flow

turbines. In

each

class o f

turbines register gates are

some

times used outside and sometimes

inside o f

the

guide chutes.

Outside

register

gates, adapted to the

Jonval

type

o f

wheels and to

plain

inward-flow

tur

bines,

w e r e named from

their

similarity

to

a common

hot-air register.

Such wheels

are

o f

small

capacity in proportion to their weight and diameter. Obstructions readily catch in

the gate and

chute

openings

and prevent the gates from being c l o s e d tightly,

and

the down

ward

pressure o f

the

water

o n the register ring makes it

difficult to open.

When the

regis-

teris partially c l o s e d ,

the

usefulness o f the

guide passages

i s in part

nullified

and the result

ing e f f i c i e n c y o f the wheel i s diminished.

The inside

register gate i s

placed

between the chute

ring

and

w h e e l

runner instead

o f

being

outside

o f

both.

It

i s

sometimes applied to

wheels

o f

the

American

type

having inlet pas

s a g e s parallel

to

the

axis

a s we l l a s

to Jonval

w h e e l s , in

which the inlet

passages are in a

plane at right

angles

to the

wheel axis.

Cylinder gates are applied to turbines o f the

Fourneyron

and American

types,

but not to

Jonval turbines.

The cylinder

gate

moves over the

inlet ports

in a

direction parallel to its

axis, cutting o f f

the

supply at the top

o f

the guide passages instead

o f

at the side,

as

does a

register

gate.

The

inside

cylinder

gate i s

the form o f

gate most

commonly

used o n wheels o f

the

Amer

ican type. It consists o f a

cast

ring having a

width

equal to the depth o f the inlet

o f the

buckets, supported

by counterbalance weights and moved

by

gearing. By moving it

up

o r

down

the depth

o f

the inlet

passages

is

increased or diminished

as desired.

It

s

commended

by its

e a s e

o f

operation and

its

freedom

from c l o g g i n g . When it

i s

partially closed the con

traction o f the water in passing

the sharp

metal lip o f

the

gate causes swirls and

eddies to

form

in

the upper

part o f

t h e ,

buckets. The smooth

curved form o f the guiJe passages

is

fully effective

only when

the

w h e e l is running with

the

gate w i d e open. In order to lead the

water smoothly into

the

buckets at al l gate openings, a

set

o f

"false

guides," o r

garnitures,

is

sometimes attached to the

lip

o f the gate cylinder to prevent

the

breaking

or throttling

o f

the

inflowing water, b

Another

device intended to

prevent

inefficient

operation

when

the

buckets

are only par

tially f i l l ed , a s at part gate, consists in

the

u s e

o f

division plates, by which the water

is

entirely shut out

o f

the upper part

o f

the

w h e e l

when

it

i s

operating at

part

gate.

This

makes

the

turbine, in effect, a s e r i e s

o f

water wheels

placed

o n e

above

another.

Such

water

wheels are commonly called double turbines. They may, however, be distinguished from

another style

o f double turbines,

the

Leffe l , in which two essentially different wheels

are

combined and mounted o n

the

same

shaft for the purpose

o f increasing

the

capacity

o f

the

turbine

without

increasing its

diameter.

When

an inside

cylinder gate i s

raised, an open

space

an inch or more wide

i s left

between

the

guide

chutes and buckets.

In

order to

avoid

this and to conduct

the

water

a

Tyler,

W . W . , T h e

evolution o f

the

A m e r i c a n

type

o f

water

w h e e l : Jour.

Western Soc. Eng. vo l .

3 ,

C h i c a g o ,

1898.

&Wet>ber,

S a m u e l , Ef f i c i e nc y

o f

turbines

as

a f f e c t e d

byform

o f

gate: Trans.

Am.

S o c . M e c h . E n g . ,

1 N S 2 .


18/138

MECHANICAL PRINCIPLES.

17

more

perfectly

to the w h e e l , an outside

cylinder

gate has

been devised,

called a "sleeve

gate," consisting o f a

cylindrical

ring slipping outside

o f

both

runner and

chute ring.

Wicket

or

pivot gates, a s

the

terms are

applied to

the American type

o f

turbines, are a

combination o f gates

and guide passages. The leaves o f

the

guide ring are

so

pivoted o n

their centers

a s

to

balance

and

swing by

levers and

gearing. Their

inner

ends

approach

or

recede from o n e another, increasing

or

cutting o f f the supply to the w h e e l runner a s desired.

A s usually constructed, al l

the

gate leaves move simultaneously: a modification consists in

a

series o f

hinged gates,

which

c l o s e

o n e

after another

a s it i s

desired to

decrease

the

power.

When a gate

i s

opened

at

all,

it

is

opened full width, and

the

number o f fractional gate

open

ings at which

the

wheel can

operate

is

determined by the

number o f gates.

Pivot

or

wicket gates are conducive to

high

part-gate e f f i c i e n c y provided they are so

con

structed a s

not

to change the

"entrance

angle " o f

the

water a s it strikes the buckets at part

gate.

Cylinder-gate turbines

may

be

so

designed a s to

yield their maximum e f f i c i e n c y

when

running at about

three-fourths

gate, the depth

o f

buckets

being

so great that

the

discharge

i s

"choked"

and

s o m e e f f i c i e n c y lost

at

full

gate.

In

this

way a good e f f i c i e n c y scale for

part

gate i s

obtained

with cylinder-gate turbines.

Pivot gates

contain

many parts and

are a s a rule more liable to

obstruction,

leakage,

and breakage

than

cylinder

gates. They are, however, extensively

used with

very satisfactory

results.

MECHANICAL

PRINCIPLES

OF THE TURBINE.

N o

attempt

wil l

be

made

to

enter

into the mechanical principles

o f the

turbine from a mathematical stand

point, a s the theoretical equations o f

relation are long,

involved, and vo

luminous in

development.

Only a

very general discussion

o f

the subject

wi l l

therefore

be given.

The,

principle o f reaction, a s operat

ing in turbines, i s

illustrated

in f ig. 9.

If

the

w h e e l

W

w e r e

held rigid,

the

water

would

spout

from

the

o r i f i c e s

A,

B,

and

O

with

a

velocity due to the head H. If pistons similar to

P

w e r e

fitted

in the o r i f i c e s , these

pistons

would

bo driven

outward by

the pressure.

If, now,

the

pistons were held rigid, but the

wheel w e r e f r e e

to

revolve,

the pistons

would be forced

outward

a s before

relative to the

wheel,

but the w h e e l must then revolve.

The

water head H exerts a direct pressure o n

the

pistons,

and in accordance

with

Newton's second l a w

o f motion,

an equal and opposite pressure o r

reaction

i s

exerted outward against the back walls M, M, M o f the. arms A, B, and G .

Sim

ilarly,

i f the pistons w e r e removed, and i f the w h e e l w e r e free to revolve,

the

unbalanced

pressure

against the

back o r

outer

walls

M,

M,

M

o f

the

arms would cause it to

revolve and

with a peripheral

velocity

nearly equal to that

"due

to

the

head H.

The

theorem

o f

Torricelli requires

that

the water

shall

issue

from an

o r i f i c e

with

a

velocity

equal

to that acquired by a body falling through a

height equal to

the head.

In the c a s e o f

the

Barker's

mill

the o r i f i c e itself

i s

moving with this velocity

and

in a con

trary direction. Hence the water wil l

have

the required velocity

relative

to

the

w h e e l ,

but

wil l

have n o

velocity

relative to the earth and wi l l

drop

nearly inert

from

the

o r i f i c e s . This

simple phenomenon has been carefully traced

out,

in

order

that its application in the

l e s s

evident

example

o f

a

turbine bucket

may

be made

clear.

IKE 180 06 2

FIG. 9. Diagram

illustrating

the principle o f reaction.

The figure

represents a Barker's

mill o f

the

Whitelaw

type.


19/138

1 8

TURBINE WATER-WHEEL

TESTS

AND

POWER

TABLES.

FIG. 10. Diagram illustrating impulse against curved

vanes.

Let

A, f ig. 10 , represent

a

s i n g l e bucket

in

the vane ring

o f an

outward-discharge turbine,

the

inner

or guide

ring

being

removed. Assuming

the

bucket to be attached to the axis

o f

the

turbine

by

the

radial arm

B,

the similarity

o f

conditions to those shown in fig. 9

is

obvious.

This illustration applies equally

we l l

to either an outward, inward, o r

downward

discharge

turbine,

so

far

a s

reaction

i s

concerned.

Inasmuch

a s

the bucket A

revolves,

the water must enter the bucket, if

at a l l ,

with

a

tangential

velocity equal to the v e l o c

ity o f the bucket and

in

the

same

direction. Guide

chutes

facilitate

the action by

properly directing the

current o f

water in entering

the

bucket,

a s

indicated

at C ' , f ig . 1 0.

Action by

impulse against a mov

ing vane

takes place

a s

f o l l o w s :

First

consider

the

vane

V,

f ig.

1 1 ,

a s stationary. The jet from a guide

chute enters the bucket

in

the

direc

tion

A

B and

leaves

it in the direction

C D,

so that

its direction o f motion is

changed through

the

angle

B E C.

If the water spouting from the

guide

chute

A would

have reached B

at

the

same time that

it

actually

reaches C , then

A

C would represent

the resultant velocity. The l i n e A C

comprises two components (1)

the initial

velocity

A

B and (2) a velocity imparted by the vane V.

From

the parallelogram o f forces w e find

graphically

for

the

latter

the

value B

C.

This force i s exerted a s a

push

against

the vane,

tending to rotate it o n its

axis.

It can d o

work by

causing the vane to

move forward or

to

revolve

against

resistance,

and the amount o f work

done D

wil l

be

represented by a com

ponent

o f the

force B C (modi

f i e d by the motion o f the vane)

parallel to

the

line

o f

motion

and acting

through

the dis

tance v where v i s the

velocity

o f

the

vane i.

e.,

the velocity

o f

rotation

o f

a turbine.

If the vane V w e r e properly

curved and moved with such

velocity relative to

that o f the

jet that the jet left its outer

end with a

backward

velocity

equal to,the forward

velocity o f

the

wheel, then

the

jet

would

FIG. 11. Diagram illustrating t h e o r y o f

m o v i n g v a n e s .

have no velocity relative to the

earth and

would

drop inert, its entire energy having been imparted to the vane.

With

most forms o f gates the s ize o f the jet i s decreased a s the , gate i s closed, the bucket

area remaining unchanged, so

that

the w h e e l

operates mostly by

reaction at full

gate and

by impulse to an

increasing

extent

a s

the gate is c l o s e d .

Hence, the speed

o f maximum

. , n ,

,

. peripheral velocity .

e f f i c i e n c y varies a s the gate i s c l o s e d .

1

he ratio , -, , V lormaximumernciency

for

a

36-inch Hercules turbine

i s

given in

the subjoined

table.


20/138

MECHANICAL PKDSTCIPLES.

Velocity

a t

various gate openings

for a 36-inch

Hercules

cylinder-gate

turbine.

1 9

Proportional

gate

opening.

Full.

0.806

.647

.489

.379

Maximum


Per

cent.

&o.60

87. 1

86.3

S O

73.1

Peripheral

velocity.

Velocity

duo

head.

0.677

.648

.641

.603

.58.5

Centrifugal

f o r c e

a l s o plays an important part

in

turbine

action.

The complete theory

o f the turbine, including consideration o f friction and centrifugal

f o r c e ,

involves intricate

mathematical

analysis. The

principal

results to which it leads are a s follows:

Given

the head and

quantity

o f

water and

speed

required, theory indicates

the

diameter

o f w h e e l and

the

initial

and

terminal angles o f the

vanes.

It d o e s not determine the. form o f

the vanes,

the curved

surfaces o f which are

usually

made

up o f circular

arcs for simple

inward-,

outward-,

and downward-flow turbines. Neither

is

the number

or

the depth o f the

buckets determined, except that their normal sections shall be such a s to give

the

water tho

required

velocities in passing

through.

Theory d o e s not indicate

the

numbers o f

guides or

buckets

most

desirable. If, however,

they

are too f e w , the

stream

wil l not properly

f o l l o w

the f l o w lines indicated by theory. If

the buckets

are too small

and

too numerous,

the surface-friction factor wi l l

be

large.

It

i s

customary to make

the

number o f guide chutes

greater

than

the

number

o f

buckets,

so

that

any object

passing

through

the

chutes

wil l be

likely

to'pass through the

buckets

a l s o .

In

a

Jonval turbine the guide ring and bucket ring have equal radii. In

the

Francis,

Thomson,

and

American

types

the

radius o f

the guide

ring

is larger, requiring oftentimes the

thickening o f the

guide

partitions

in order to give

the

water

the proper initial velocity

where

it enters the

buckets.

HORSEPOWER AND

EFFICIENCY

OF

TURBINES.

The

energy

or

capacity

for doing

work-resulting from a weight W falling through a height

H

is

Energy in

foot-pounds=Tf H.

A hoisepower was defined by

James

Watt a s

the capacity

to perform work at

the

rate o f

3 3 , 0 0 0

foot-pounds o f

energy

expended per minute.

If the weight o f a

cubic foot o f

water

i s w >

and

the f l o w

o f a stream

is Q cubic feet

per

minute, then the theoretical horsepower wil l be

WE =QwE

33,000~33,000

Takingw, the weight o f water,

at 6 2 . 4

pounds per cubic

foot,

the factors for obtaining the

theoretical horsepower are the following:

0.1135XffXcubic

feet

per

second.

0.001S9x#Xcubic feet per minute.

0.000253X-0XU. S . gallons

per

minute.

0.3643X-0XU.

S.

gallons

per 2 4

hours.

0.00227X#XCalifornia

miner's

inches

(=0.02

second-foot).

0.00295X#XColorado

miner's inches (=0.026 second-foot).

0.0007S9v/2gX#

L'XF (vent in square inches).

0.00632X.EPXF

(vent in square inches).


21/138

2 0

TURBINE WATER-WHEEL TESTS

AND

POWER TABLES.

The horsepower

o f

a stream decreases about one-fourth

o f

1 per cent

with

a variation

of

the temperature o f

the

water from 40 to 75 F.

For

precise calculations

the exact

weight

o f pure water

may be useful.

Weight

and dimensions ofdistilled

water

a t stated temperatures.

[ W e i g h t

in

p o u n d s . ]

Tempera

ture,

de

grees Fah

renheit.

32

39.3

50

60

70

80

Relative

density.

0.

99987

1 .

00000

.99975

.

99907

.99802

. 99669

Weight

per cubic

foot.

62. 416

6 2 . 4 2 4

6 2 . 4 0 8

62. 366

6 2 . 300

62. 21 7

Weight

per cubic

inch.

0. 0361

.0361

.0361

.0361

.

03607

. 03602

Weight of

column 1

inch

square,

1

foot high.

0. 4334

. 4 3 3 5

. 4 3 3 3

. 4 3 3 0

. 4 3 2 6

. 4 3 2 0

Weight

per

U. S .

gallon.

8 . 345

8.

3 4 5 4

8. 3 4 3 3

8 . 3 3 83

8. 3295

8 . 3 1 84

Cubic

feet

per

ton.

32.

04 3

3 2 . 0 3 9

32. 04 7

3 2 . 0 6 9

32.

103

32. 145

Weight

per

cubic yard.

1 ,

685.

2 3 2

1,685.448

1 , 684.

908

1,683.882

1 ,

682. 100

1 , 679.

85 9

a Smith, Hamilton, Hydraulics.

b

Maximum density.

In

practice

the theoretical power

i s always

to be multiplied

by

an e f f i c i e n c y

factor

E to

obtain

the net power

available on

the turbine shaft a s determinable by dynamometrical test.

Manufacturers' rating tables are based o n e f f i c i e n c i e s usually between 7 5 and 8 5 per

cent.

In

selecting

turbines

from

a maker's

list

it i s often important to

know the rated e f f i c i e n c y .

This may be obtained by the following

formula

E==

tabled


H. P.= abled horsepower, and

Q=tabled discharge (C.

F.

M.)

for

any head H.

u,_ 33.000XH.P. _ _ _

H.P.

The

tabled


for a number o f styles and s i z e s o f

turbines

are

shown

in the

accom

panying table.

Rated

efficiency of

water

wheels.

F r o m m a n u f a c t u r e r s ' power tables . ]

Name

of

wheel.

Do........................................................

Do........................................................

Do........................................................

Do........................................................

Do........................................................

Do........................................................

Do........................................................

Diameter

in

inches.

2 4

4 8

4 5

4 8

2 4

4 8

24

4 8

2 2

4 4

2 5

4 8

2 4

4 8

Percentage

of efficiency

at 10-foot

head.

81. 52 0

8 0. 8 00

80 . 7 5 4

79. 877

7 9 . 86 9

80.004

79.

94 5

80.000

79.

93 7

8 0. 110

8 0. 010

7 9 . 8 3 0

7 9 . 90 5

7 9 . 91 4

7 9 . 9 1 4

Percentage

o f e f f i c ie n c y

at 4 0 - f o o t

head.

79.856

79 856

80.800

79.

94 4

79. 93 1

79.

91 3

79.

907

79 . 9 06

79 . 9 07

79. 841

8 0. 126

79.890

79. 776

79. 936

79 . 9 33


22/138

HORSEPOWER A W D

EFFICIENCY.

21

The

e f f i c i e n c y at

which

wheels are rated by the builders varies slightly with the s ize o f

the

w h e e l , a s we l l a s

with

the head,

in

many

c a s e s .

Owing to

the

different

weights o f

water

assumed,

etc.,

the


o f wheels intended to be rated

at

80 per

cent differ

slightly

from that amount where computed from the

manufacturer's

power

tables.

Prior to the

classical

experiments o f

James B . Francis on the

f l o w o f water

over w e i r s in

1 8 5 2 at the.

lower

locks in

Lowell

the diversity o f formulas used for

calculating

f l o w through

turbines makes the results o f

early

tests incomparable o n e with another, and the accuracy

o f

s o m e

later experiments

preceding the building

o f the present

Holyoke testing f l u m e is s o m e

what

in

doubt.

It can

hardly

be said that there has been a progressive growth in the e f f i c i e n c y

o f tur

bines, a s the

following

outline

o f the results o f successive

series

o f tests

wil l show:

In 1 7 5 9 James Smeaton reported tests o f 2 7 undershot water w h e e l s showing


varying

from

2 8 to

3 2

per cent. Similar tests

o f

1 6 overshot wheels showed e f f i c i e n c i e s

varying from 7 6 to 9 4 per cent.^

In

1 8 3 7 M . M o r i n

tested

several Fourneyron turbines. O n e at St. Blaise

showed

an effi

ciency o f 8 5

per cent under

3 5 4

feet

head.

For

another,

under

a lower fa l l , 88 per cent effi

ciency

is

claimed, b

In 1 8 4 3 Elwood Morris introduced and tested Fourneyron turbines in the United States.

Turbines

in

Rockland

mills

and

Dupont

powder

mills,

Wilmington,

Del. , showed

7 0 and 7 5

per

cent

maximum e f f i c i e n c y , respectively.

In 1 8 4 4 Uriah A . Boyden

built

at Lowell the first Fourneyron turbine used in New Eng

land,

which showed

o n

completion

an e f f i c i e n c y

o f 7 8

per cent, c It i s claimed

that

s o m e o f

Boyden's later turbines

showed

an e f f i c i e n c y , o n

test,

o f 8 8 to 9 2 per cent.

In

18 59

and 1 8 6 0

competitive tests o f

1 9 wheels at

Fairmount

Park waterworks showed

e f f i c i e n c i e s a s

f o l l o w s :

Results of tests of turbines a t Fairmount Park, Philadelphia, Pa., in 1859 60.

Efficiency.

Number of

turbines.

1

0

2

Efficiency.

Number

of

turbines.

4

3

2

1

In 1 8 7 6

C e n t e n n i a l tests s h o w e d maximum

e f f i c ienc ie s

a s f o l l ow s

f o r

17 w h e e l s :

Results of ests

of

turbines a t Centennial Exposition, a t Philadelphia, in

1876.

Efficiency.

Number of

turbines.

3

4

Efficiency.

Number of

turbines.

5

4

1

The large

majority

o ' f

turbines

sold at the

present time are made

at

the shops o f f i v e

o r

six

builders whose wheels have been

frequently

tested.

The

average full-gate e f f i c i e n c y

shown in

recent

Holyoke tests

o f

standard patterns i s

c l o s e

to 80

per

cent.

S o m e early

wheels showed

very

high e f f i c i e n c i e s ,

but prior to the

building o f

the

Holyoke

flume the large majority w e r e o f low e f f i c i e n c i e s .

o Evans, Oliver, Millwright's Guide,

Philadelphia,

1853 , pp. 131-154 .

6 Journal Franklin

Institute,

October to December,

1813.

c Francis, J. B., Lowell Hydraulic Experiments.


23/138

22 TURBINE WATEK-WHEEL TESTS

AND

POWER TABLES.

During the past thirty years the

'general

standard

o f

e f f i c i e n c y o f turbines has been

steadily raised, although the maximum attained may

not

exceed that

o f

some

early

forms.

The uniformity o f

each maker's

wheels, a s we l l as

their strength

water wheel turbine

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