TABLE OF CONTENT

TOPIC PAGE

1.0 INTRODUCTION 1

2.0 OBJECTIVE 3

3.0 PROCEDURE 4

4.0 RESULT

4.0.1 SAMPLE CALCULATION

4.0.2 INPUT POWER TABLE

5

5

6

5.0 DISCUSSION 8

6.0 CONCLUSION 9

REFERENCE 10

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1.0 INTRODUCTION

There are two types of turbines, reaction and the impulse, the difference being the manner of

head conversion. In the reaction turbine, the fluid fills the blade passages, and the head change or

pressure drop occurs within the runner. An impulse turbine first converts the water head through

a nozzle into a high-velocity jet, which then strikes the buckets at one position as they pass by.

The runner passages are not fully filled, and the jet flow past the buckets is essentially at constant

pressure. Impulse turbines are ideally suited for high head and relatively low power. The Pelton

turbine used in this experiment is an impulse turbine. The Pelton turbine consists of three basic

components as shown in Figure 1: a stationary inlet nozzle, a runner and a casing. The runner

consists of multiple buckets mounted on a rotating wheel. The jet strikes the buckets and imparts

momentum. The buckets are shaped in a manner to divide the flow in half and turn its relative

velocity vector nearly 180°.

Figure 1: Schematic of an impulse turbine

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The primary feature of the impulse turbine is the power production as the jet is deflected by the

moving buckets. Assuming that the speed of the exiting jet is zero (all of the kinetic energy of

the jet is expended in driving the buckets), negligible head loss at the nozzle and at the impact

with the buckets (assuming that the entire available head is converted into jet velocity), the

energy equation applied to the control volume shown in Figure 1 provides the power extracted

from the available head by the turbine

P availableQH available (1)

where Q is the discharge of the incoming jet, and Havailable is the available pressure head on the

nozzle. By applying the angular momentum equation (assuming negligible angular momentum

for the exiting jet) to the same control volume about the axis of the turbine shaft the absolute

value of the power developed by the turbine can be written as

P ωT 2π NT (2)

where ω is the angular velocity of the runner, T is the torque acting on the turbine shaft, and N is

the rotational speed of the runner. The efficiency of the turbine is defined as the ratio between

the powers developed by the turbine to the available water power

h=P

p (available)

In general the efficiency of the turbine is provided as isoefficiency curves. They show the

interrelationship among Q, w, and h. A typical isoefficiency plot is provided in Figure 2.

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Figure 2: Isoefficiency curve for a laboratory-scale Pelton turbine.

Under ideal conditions the maximum power generated is about 85%, but experimental data

shows that Pelton turbine are somewhat less efficient (approximately 80%) due to windage,

mechanical friction, back splashing, and non uniform bucket flow.

2.0 OBJECTIVE

To learn the design and function of a Hydraulic turbine.

To determine the impulse turbine characteristic

To determine the power curves characteristic

To produce the data of output power and torque against speed

To test the output performance at different nozzle setting

To determine the optimum efficiency point

To compare the mechanical & electrical power

To determine the generator efficiency

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3.0 PROCEDURE

The apparatus was set up with Pelton turbine mounted on the stainless steel frame.

The control valve was ensured to be fully opened and slowly close the bypass valve.

The nozzle jet was preset to be fully opened position for this experiment. The water from

the nozzle jet will make the turbine to rotate.

The pump was switched on to let the water flow into the nozzle.

The by-pass valve was adjusted slowly until the turbine reaches the maximum speed.

The nozzle was adjusted to find out the maximum performance point (with suitable

speed, flow and pressure).

The reading for each meter was recorded.

Now, the Load On/off switch was switched on to load the generator.

The reading for each meter was recorded and the DC Ampere showed the ampere

produce from generator.

The knob of rheostat was adjusted by turning anti-clockwise. The speed of generator was

reduced. The reading for each meter was recorded. The reading for every 200 RPM

decrement was recorded.

Test until the ampere meter show the maximum value, (HHHH).

The by-pass valve was not adjusted during run the experiment.

The reading was put in table and the output power and efficiency of turbine was

calculated.

The graph was plotted and the optimum working point was found.

The experiment was repeated by different nozzle opening.

4.0 RESULTS

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Table 1: Hydraulic Input Power (Without Load)

NO. GENERATOR

TORQUE (Nm)

GENERATOR

SPEED (rpm)

WATER

PRESSURE

(bar)

WATER

PRESSURE

(Pa)

WATER

FLOW

RATE

(lpm)

WATER

FLOW

RATE (m3/s)

VOLTAGE

(Vdc)

CURRENT

(Adc)

1 0.03 2497 2.13 213000 44.5 0.000383 21.8 0.0

2 0.03 2300 1.82 182000 43.6 0.000406 20.7 0.0

3 0.03 2102 1.60 160000 42.4 0.000366 18.9 0.0

4 0.02 1903 1.38 138000 39.9 0.000342 15.2 0.0

5 0.02 1704 1.22 122000 36.4 0.000334 11.7 0.0

6 0.02 1503 1.05 105000

7 0.02 1300 0.89 89000

8 0.02 1101 0.75 75000

9 0.01 904 0.61 61000

10 0.01 704 0.50 50000

11 0.01 500 0.40 40000

12 0.01 302 0.31 31000

13 0.01 166 0.25 25000

Table 2: Hydraulic Input Power (With Load)

NO. GENERATOR

TORQUE (Nm)

GENERATOR

SPEED (rpm)

WATER

PRESSURE

(bar)

WATER

PRESSURE

(Pa)

WATER

FLOW

RATE

(lpm)

WATER

FLOW

RATE

(m3/s)

VOLTAGE

(Vdc)

CURRENT

(Adc)

1 0.14 2031 1.74 174000 46.8 0.000354 21.9 0.9

2 0.25 1830 1.74 174000 46.6 0.000352 18.7 2.1

3 0.36 1627 1.74 174000 47.0 0.000355 15.6 3.0

4 0.47 1365 1.74 174000 46.3 0.000350 12.0 4.1

5 0.55 1169 1.75 175000 46.7 0.000353 9.3 4.8

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4.0.1 SAMPLE OF CALCULATION

AVERAGE SPEED (rad/s) = Average speed (rpm) * 2π/60

= 2050*2π/60

= 214.68 (rad/s)TORQUE (Nm) = 0.02 Nm

4.0.2 INPUT POWER (HYDRAULIC) (W)

Table 3: Turbine Equation (Without Load)

Average

speed

(rad/s)

Torque

(Nm)

Input

Power

(hydraulic)

(W)

Output

Power

(Mechanical)

(W)

Efficiency

(Turbine)

Output

Power

(Electrical)

(W)

Efficiency

(Generator)

214.68 0.02 56.301 4.294 0.076 0.00 0.00

193.21 0.02 56.434 3.864 0.068 0.00 0.00

171.00 0.02 41.358 3.420 0.083 0.00 0.00

141.06 0.02 30.780 2.821 0.092 0.00 0.00

131.95 0.01 21.376 1.320 0.062 0.00 0.00

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50

0.010.020.030.040.050.060.070.080.09

0.1

Efficiency vs output power

turbinegenerator

Graph 3: Efficiency vs output power for without load (Turbine and Generator).

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Table 4: Turbine Equation (With Load)

Average

speed

(rad/s)

Torque

(Nm)

Input

Power

(hydraulic)

(W)

Output

Power

(Mechanical)

(W)

Efficiency

(Turbine)

Output

Power

(Electrical)

(W)

Efficiency

(Generator)

212.68 0.14 60.60 29.78 0.49 19.71 0.66

191.64 0.25 61.25 47.91 0.78 39.27 0.82

170.38 0.36 61.77 61.34 0.99 46.80 0.76

142.94 0.47 60.90 67.18 1.10 49.20 0.73

122.42 0.55 61.78 67.33 1.08 44.64 0.66

Graph 4: Efficiency vs output power for with load (Turbine and Generator)

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Optimum Working point

5.0 DISCUSSION

Based on graph 3, for the turbine without load, it shows that the higher efficiency at

141.6 rad/s which is 0.092 or 9.2% efficiency. Thus at average speed 141.6 rad/s gave the best

performance for turbine. Besides that, for graph 4 which is turbine with load, it shows that the

higher efficiency occur at average speed of 170.38 rad/s that is with the efficiency of 0.99 or

99%. It can be conclude that the best performance for turbine with load occur at average speed of

170.38 rad/s.

For the maximum power, based on graph 3 for without load turbine showed that

maximum power was at 4.294 W and for without load gave 67.33 W for maximum power

produced. To know the performance effect of the turbines, we can look in two aspects. First is

the nozzle setting and second is guide vane setting. For the nozzle setting, the decrement of the

nozzle opening gave the increment of the flow velocity while for the guide vane setting by

opening the angle of 180° gave the higher momentum for the turbine to rotate at highest speed.

The function of nozzle and vane use in this experiment is the nozzle jet strikes the buckets and

imparts momentum. The buckets are shaped in a manner to divide the flow in half and turn its

relative velocity vector nearly 180°.

The working principle of this experiment is turbines convert fluid energy into rotational

mechanical energy. For the Francise turbine, It is an inward-flow reaction turbine that combines

radial and axial flow concepts. It mostly used in electrical power production. For the Pelton

turbine, the high speed water jets emerging from the nozzles strike the buckets at splitters, placed

at the middle of a bucket, from where jets are divided into two equal streams. These stream flow

along the inner curve of the bucket and leave it in the direction opposite to that of incoming jet.

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The high speed water jets running the Pelton Wheel Turbine are obtained by expanding the high

pressure water through nozzles to the atmospheric pressure. The high pressure water can be

obtained from any water body situated at some height or streams of water flowing down the hills.

For the Kaplan turbine, The working head of water is low so large flow rates are allowed in the

Kaplan Turbine. The water enters the turbine through the guide vanes which are aligned such as

to give the flow a suitable degree of swirl determined according to the rotor of the turbine. The

flow from guide vanes pass through the curved passage which forces the radial flow to axial

direction with the initial swirl imparted by the inlet guide vanes which is now in the form of free

vortex.

The axial flow of water with a component of swirl applies force on the blades of the rotor

and loses its momentum, both linear and angular, producing torque and rotation (their product is

power) in the shaft. The scheme for production of hydroelectricity by Kaplan Turbine is same as

that for Francis Turbine. The difference between Francis, Pelton and Kaplan turbine are Pelton

turbines are most suitable for high head situations, for which the head can be converted into a

high speed jet. Francis turbines are used for intermediate heads, and Kaplan for the lowest heads.

6.0 CONCLUSION

The best performance of the turbine can be known from the average speed of the turbine, for the

turbine with the load need higher average speed compared to turbine without load to get the best

performance of the turbine. For the maximum power of the turbine produced showed that with

load in turbine can get higher power compared to the turbine without load. For the three

difference turbines, even this turbines got each specialty but the aim of this use of turbines were

to convert fluid or gas energy into rotational mechanical energy and electrical energy.

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REFERENCE

1) Robertson, J.A. and Crowe, C.T. (1993). Engineering Fluid Mechanics, 5th edition,

Houghton

Mifflin, Boston, MA.

2) White, F.M. (1994). Fluid Mechanics, 3rd edition, McGraw-Hill, Inc., New York, NY.

3) http://www.knowenergysolutions.com/conventional-energy/oil-and-gas/mechanical-

engineering/the-pelton-turbine/

4) http://www.knowenergysolutions.com/conventional-energy/oil-and-gas/mechanical-

engineering/kaplan-turbine/

5) Layton, Edwin T. "From Rule of Thumb to Scientific Engineering: James B. Francis and

the Invention of the Francis Turbine," NLA Monograph Series. Stony Brook, NY:

Research Foundation of the State University of New York, 1992.

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