# JNTU Exam Papers

## Prime Movers and Mechanical Measurements 1st Sem 2008

SET-3

1. (a) Define specific speed and derive the equation.

(b) A reaction turbine operating with 93 percent hydraulic efficiency utilizes 900liters/sec

of water. Its peripheral velocity at inlet is 24m/sec while velocity of whirl is

18m/sec. If the area of flow at inlet is 0.4sq.m, find the guide vane angle at

outlet and the horse power generated by the turbine if the discharge is radial.

[8+8]

2. (a) What is the hydraulic function of a air vessel?

(b) A single acting reciprocating pump without air vessel has a plunger of 8cm

diameter and a stroke of 12cm.It draws water from a sump 3m below the pump

through a suction pipe 3 cm diameter and 5m long. It delivers water to a tank

12m above the pump through a delivery pipe 2cm diameter and 15m long. If

separation occurs at a pressure of 67 KN /m2 below atmospheric pressure, find

the maximum speed at which the pump may be operated without separation.

[6+10]

3. What is a condenser? Name the different types of condensers and describe the

operation of surface condenser with a neat sketch? 

4. (a) Show that the thermal efficiency of a regenerative cycle is always higher than

that of a simple Rankine cycle.

(b) A Carnot engine works between the pressures of 28 bar and 0.15 bar using

steam as working fluid. Dry-saturated steam is supplied to the engine. Find

the work done and thermal efficiency of the engine. Also find the dryness

fraction of steam at the end of isentropic expansion and at the beginning of

isentropic compression. [8+8]

5. (a) Draw the neat diagram of a regenerative power cycle? Discuss salient features?

(b) Describe the working of constant pressure heat addition open cycle gas turbine

power cycle? [8+8]

6. Compare the advantages and limitations of using venturimeter and Orifice Meter in fluid flow measurements. Comment on the conclusions you draw from the

differences. 

7. (a) Explain how a proving ring is used to measure force .

(b) Explain about phase shift in the seismic vibrometer. [8+8]

8. (a) Suggest and explain a device to measure torque delivered to a generator.

(b) List the different means normally used for torque measurement.