Fundamentals of Turbomachines — Winter 2024

Define and classify turbo-machines in detail.

Write difference between fan, blower, compressor and pump.

Draw velocity triangles at entry and exit for 2-stage Pressure-compounded impulse turbine with explain variation in pressure and velocity while flow passing through the stages.

Explain the performance charts for an axial turbine stage.

Explain cooling technique used for gas turbine blades with neat sketches.

Agas turbine nozzle pressure ratio is 2.5, pressure at entry is 1.01325 bar, and temperature is 300 K. The efficiency of nozzle is 85 %. Determine the exit Mach number, velocity at exit of nozzle. Take gama (r) = 1.4, draw h- s diagram for nozzle.

An axial turbine rotating with the speed 5000 RPM and having tip and hub diameter 700 mm and 400 mm respectively. Air angle at nozzle exit is 75º and relative angles at rotor entry and exit are 40º and 70º respectively. Draw velocity triangles for mean flow and determine: Degree of reaction, Blade to gas speed ratio, Specific work.

Explain Stalling of an axial flow compressor.

With a neat sketch explain the working principle of axial flow compressor.

A 50 % reaction, axial flow compressor runs at a mean blade speed of 40 m/s. the pressure ratio developed by the machine is 1.2. Determine the blade and air angle if the mean flow velocity was 150 m/s. condition at inlet are 1 bar and 300 K.

Write difference between axial compressor and centrifugal compressor.

Draw and explain H-Sdiagram of Axial compressor stage.

An axial flow compressor has a flow coefficient of 0.75 and the loading coefficient is 0.85. if the blades are symmetrical, calculate the blade angles and the speed of the compressor. Take axial velocity as 200 m/s and mean blade diameter as 48 cm.

List the losses in centrifugal compressor.

Write a short note on surging and choking in centrifugal compressor stage.

Explain slip factor and its effect on flow and pressure ratio in the stage of centrifugal compressor, also derive the Stodola’s relation for slip factor. OR1

Draw sketches of the three types of impellers and the velocity triangles at their exits.

Define: Utilization factor, Flow coefficient, Work loading coefficient, Total to total efficiency.

With the help of diagram, explain the various components of centrifugal compressor. Also explain role of various components described.

Write six differences between axial turbine and radial turbine.

Explain radial equilibrium and derive the equation for radial equilibrium.

Derive expressions for spouting velocity and stage efficiencies for radial turbine.

Defne: Design condition, Off design condition, Matching point.

Write the steps to find equilibrium point in a turbojet engine.

Explain General matching procedure of jet engines.