fmhm 7

8/4/2019 fmhm 7

1/8

Code No: X0222/R07 Set No. 1

II B.Tech I Semester Supplementary Examinations, May 2010FLUID MECHANICS AND HYDRAULIC MACHINERY

(Electrical & Electronic Engineering)Time: 3 hours Max Marks: 80

Answer any FIVE QuestionsAll Questions carry equal marks

1. (a) State Newtons equation of viscosity and give examples of its application.

(b) An oil of viscosity 5 poise is used for lubrication between a shaft and sleeve.The diameter of shaft is 0.5 m and it rotates at 200 rpm. Calculate the horsepower lost in the oil for a sleeve length of 100 mm. The thickness of the oilfilm is 1.0 mm. [8+8]

2. (a) What do you mean by turbulence ?

(b) What do you mean by one, two, three dimensional flow?

(c) Derive the continuity equation for one dimensional fluid flow. [2+6+8]

3. (a) Derive an equation for discharge of a venturimeter.

(b) Explain why Cd of a venturimeter is more than that of orifice meter.

(c) A horizontal venturimeter with inlet and throat diameters 300mm and mmrespectively is used to measure the flow of water. The pressure intensity atinlet is 130KN/m2. While the vaccum pressure head at the throat is 350mm

of mercury. Assuming that 3% of head is lost in between inlet and throat, findCdof venturimeter and rate of flow. [6+2+8]

4. (a) Derive an expression for the force exerted by a jet striking the curved plate atone end tangentially when the plate is symetrical.

(b) A jet of water 120 mm in diameter and moving with a velocity of 25m/secstrikes normally on a flat plate. Determine the power developed and theefficiency of the system when

i. the plate is stationary

ii. the plate is moving with a velocity of 8m/sec in the direction of the jet.And

iii. the plate is moving with a velocity of 8m/sec towards the jet. [7+9]

5. (a) Write what you understand by hydroelectric power station? What are itstypes ? Discuss the type where water is recycled.

(b) What power can be developed at a hydropower plant site given the followingdetails.Drainage area = 600 Km2

Uniform rainfall over drainage area = 200 cm.Water loss in run off = 15 cmExpected net head at the plant = 50m.Efficiency of turbine = 98% [8+8]

1 of 2ase purchase PDF Split-Merge on www.verypdf.com to remove this watermark.

8/4/2019 fmhm 7

2/8


6. (a) What are the functions of a draft tube in a reaction turbine ? Derive theequation for its efficiency.

(b) A mixed flow reaction turbine has a draft tube of inlet diameter 1.5 m andis set 2 m above tail race level. A vacuum gauge connected to the draft tubeindicates a reading of 5.2 m of water. Find discharge of the turbine. Assumethe draft tube efficiency as 85%. [8+8]

7. (a) What is governing of turbines ? How can you govern a reaction turbine ?Explain the governing mechanism for reaction turbine with a neat sketch.

(b) A turbine operates under a head of 45m at 280 rpm. The discharge is 10m3 /sec and efficiency is 87 %. Find

i. Power developed

ii. Specific speed.

[10+6]

8. (a) Discuss

i. Manometric efficiency

ii. Mechanical efficiency

iii. Volumetric efficiency

iv. Overall efficiency and

v. NPSH of a centrifugal pump.

(b) Explain how the number of pumps can be decided to be connected in seriesto deliver the water to a required height at required rate. [10+6]


8/4/2019 fmhm 7

3/8





1. (a) State Newtons equation of viscosity and give examples of its application.

(b) An oil of viscosity 5 poise is used for lubrication between a shaft and sleeve.The diameter of shaft is 0.5 m and it rotates at 200 rpm. Calculate the horsepower lost in the oil for a sleeve length of 100 mm. The thickness of the oilfilm is 1.0 mm. [8+8]

2. (a) Distinguish between:

i. Steady and Un-steady flow.

ii. Uniform and Non-uniform flow.

iii. Compressible and incompressible flow.

(b) A 400 m long pipe has a slope of 1 in 100 and tapers from 1.2 m dia at highend to 0.6 m dia at the low end. The discharge is 100 lit/sec. If the pressureat high end is 100 kN/m2, find the pressure at the low end. Neglect friction.

[8+8]

3. (a) Derive the Darcy-weisbach equation for friction head loss in a pipe.

(b) Water is flowing through a horizontal pipe line 1500m long and 200mm indiameter. Pressures at the two ends of the pope line are respectively 12Kpaand 2Kpa. If f = 0.015, determine the discharge through the pipe in litres perminute. Consider only frictional loss. [8+8]

4. (a) Derive an expression for force exerted by a jet on stationary inclined flat plate.

(b) A nozzle of 50mm diameter delivers a stream of water at 20m/sec perpendic-ular to a plate that moves away from the Jet at 5m/sec.find

i. the force on the plate

ii. work done and

iii. the efficiency of jet. [7+9]

5. (a) What is mass curve? Give the step wise procedure of constructing the same?What are its features and applications

(b) Define gross head and net head associated with working of turbines. Whatlosses are to be considered in finding the net head from gross head ? List theefficiencies of turbines. [8+8]

6. (a) What are single jet and multi jet impulse turbines ? Draw neat sketches andexplain.


8/4/2019 fmhm 7

4/8


(b) Show from fundamentals that hydraulic efficiency of a Pelton wheel is givenby = 2[V

1u][1 + KCos]u/V2

1with usual notation. [6+10]

7. (a) What do you mean by selection of turbines ? What are scale ratios ? Explainwith neat sketches when geometric similarity is achieved between model andprototype?

(b) A Pelton wheel turbine develops a power of 1000 Kw under a head of 75m. Ifthe head becomes 25m, what will be the power developed by the turbine.

[10+6]

8. (a) What do you understand by pumps in series and pumps in parallel ? How doyou decide whether the pumps shall be used in series or parallel.

(b) A single acting reciprocating pump running at 60 rpm delivers 0.53 m3 of waterper minute. The diameter of the piston is 200 mm and stroke length 300 mm.

The suction and delivery heads are 4m and 12m respectively. Determine

i. Theoretical discharge

ii. Coefficient of discharge

iii. Percentage slip of the pump and

iv. Power required to run the pump. [8+8]


8/4/2019 fmhm 7

5/8





1. (a) Enunciate Newtons law of Viscosity. Explain the importance of viscosity influid motion. What is the effect of temperature on viscosity of water and thatof air?

(b) A glass tube 20 mm in diameter contains a mercury column with water abovethe mercury. The surface tension of mercury in contact witht water is 0.36

N/m. Datermine the capillary depression of the mercury. Take = 1300

.[8+8]

2. (a) Define the equation of continuity. Obtain an expression for continuity equationfor a one- dimensional flow

(b) A pipe of diameter 40 cm carries water at a velocity of 25 m/s. The pressuresat the point A and B are given as 29.4 N/cm2 and 22.56N/cm2 respectivelywhile the datum head at A and B are 28 m and 30 m. Find the loss of headbetween A and B. [8+8]

3. (a) Derive an expression for head loss due to sudden enlargement of a pipe

(b) An oil of specific gravity 0.85 and viscosity 5CP flows through a pipe of di-

ameter 400mm at the rate of 50 lit/sec. Find the head lost in friction in thispipe of length 1000Km. Assume that f = 0.079/RN where RN is ReynoldsNumber. [8+8]

4. (a) Derive an expression for the force exerted by a jet striking the curved plate atone end tangentially when the plate is symetrical.



ii. the plate is moving with a velocity of 8m/sec in the direction of the jet.

Andiii. the plate is moving with a velocity of 8m/sec towards the jet. [7+9]

5. (a) What are the types of hydroelectric power stations? Write about each of them.

(b) At the site where hydroelectric plant is proposed the following details areavailable. Calculate the power that can be developed. Available head = 28 mCatchment area = 420 Km2

Yearly rainfall = 140 cmRainfall utilization rate = 68%Penstock efficiency = 94%


8/4/2019 fmhm 7

6/8


Turbine efficiency = 80%Generator efficiency = 84% [8+8]

6. (a) What is draft tube and what are its functions in a reaction turbine.

(b) Derive the equation for work done in Pelton wheel turbine from fundamentals.[6+10]

7. (a) How is geometric similarity obtained between model and prototype ? Explainwith sketches and give examples.

(b) A Francis turbine works under the following conditions. Estimate its perfor-mance when the head drops down to 45 m.The head = 60m, Speed = 1200 rpm, Discharge = 12 m3 / sec, Efficiency =88 % [8+8]

8. (a) What are the components of a reciprocating pump ? Explain its working witha neat sketch. What is the use of providing an air vessel ?

(b) The diameter of piston of a reciprocating pump is 15 cm and stroke lengthis 30 cm. The suction pipe diameter, length and suction head are 5 cm, 5mand 2.5 m respectively. The cavitation occurs at 2.0 m of water (abs) andatmospheric pressure is 10 m of water (abs).What is the maximum speed ofthe pump without cavitation ? [8+8]


8/4/2019 fmhm 7

7/8





1. (a) Enunciate Newtons law of Viscosity. Explain the importance of viscosity influid motion. What is the effect of temperature on viscosity of water and thatof air?

(b) A glass tube 20 mm in diameter contains a mercury column with water abovethe mercury. The surface tension of mercury in contact witht water is 0.36

N/m. Datermine the capillary depression of the mercury. Take = 1300

.[8+8]

2. (a) What is continuity equation? Derive the equation.

(b) Derive Euler?s equation of motion along a stream line. State assumptionsmade in the derivation. [8+8]

3. (a) Describe the principle and working of orifice meter with the help of a neatsketch.

(b) In a calibration test of an orifice meter of with orifice diameter 4cm is insertedin a pipe of 10cm diameter the mercury differential U-guage connected to themeter gives a reading of 38cm when 7.5 lit/sec of water flows through the

meter. Compute the coefficient of discharge. [8+8]4. (a) Derive an expression for the force exerted by a jet striking the curved plate at

one end tangentially when the plate is symetrical.



ii. the plate is moving with a velocity of 8m/sec in the direction of the jet.And

iii. the plate is moving with a velocity of 8m/sec towards the jet. [7+9]

5. (a) What are the types of hydroelectric power stations? Write about each of them.

(b) At the site where hydroelectric plant is proposed the following details areavailable. Calculate the power that can be developed. Available head = 28 mCatchment area = 420 Km2

Yearly rainfall = 140 cmRainfall utilization rate = 68%Penstock efficiency = 94%Turbine efficiency = 80%Generator efficiency = 84% [8+8]


8/4/2019 fmhm 7

8/8


6. (a) What is an axial flow turbines ? What are its parts ? Explain with sketches.

(b) Derive the equation for work done on the runner of an axial flow turbine from

fundamentals. [6+10]

7. (a) What do you mean by selection of turbines ? What are scale ratios ? Explainwith neat sketches when geometric similarity is achieved between model andprototype?

(b) A Pelton wheel turbine develops a power of 1000 Kw under a head of 75m. Ifthe head becomes 25m, what will be the power developed by the turbine.

[10+6]

8. (a) Draw a neat sketch of an indicator diagram for a single acting reciprocatingpump and explain its features.

(b) A reciprocating pump has a 20 cm diameter cylinder and a stroke of 120 cm.The pump delivers 5000 litres / minute of water at a static head of 80m.Friction losses in suction and delivery pipe are 2m and 18m respectively. Theslip of pump is 2% and efficiency is 90%. Determine the speed of the pumpand power required neglecting velocity head in delivery pipe [8+8]


fmhm 7

Documents