# JNTU Exam Question Papers

## Prime Movers and Mechanical Measurements 1st Sem Nov 2008

1. (a) Explain the working of Pelton wheel turbine and derive the equation for the power developed by the runner.

(b) At a hydropower plant the turbine operates under a head of 100m and consumes water at the rate of 12 m3 / sec. If the turbine runs at 240 rpm and

gives an efficiency of 90%, find the specific speed of the turbine. [10+6]

2. (a) What is the discharge into or from the air vessel? Explain?

(b) A centrifugal pump has an impeller of outer diameter 30cm and outer width of 6 cm. The velocity of flow through the impeller is constant at 2.6 m /sec.

The impeller vane is radial at the outlet. The speed of impeller is 1000 rpm and manometric efficiency is 85%. Calculate –

i. Head developed and

ii. Discharge. [6+10]

3. Draw the block diagram of steam power plant showing all the components with a brief mention of their functions. [16]

4. (a) Explain briefly why in multistage impulse turbines the first stage is often compounded for velocity and remaining having single row wheels.

(b) For a stage of impulse turbine with single acting wheel and equiangular blades, the nozzle angle is 200. The velocity coefficient for the blades is 0.83. What

is the maximum blade efficiency? If the blade efficiency is 90% of maximum values, what are the possible ratios of blade speed to steam speed? [6+10]

5. A gas turbine draws air at atmospheric pressure and 299 K. There are two stages of compression with an intercooler and the pressure ratio is 8:1 in each stage. The maximum temperature of the cycle is 800 K. Determine the thermal efficiency and work ratio if efficiency of turbine and compressor are 0.86 and 0.83 respectively.

[16]

6. An orifice having a diameter of 50mm is known to wear so that the diameter increases by 0.05 mm in each week. It is installed in a 100mm pipe. If the Reynolds

number is about 1000,000 estimate the error after 6 weeks operation. [16]

7. (a) What are various elementary accelerometers. Explain the principle of each.

(b) Explain the method of measuring force using a strain gauge. [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. [8+8]

JNTU Prime Movers and Mechanical Measurements Exam Paper Nov 2008