ME-603-A Turbomachinery - Jun 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 6 Marks
   aExplain the term degree of reaction for any steam turbine.
   How to answer

   • Define degree of reaction as ratio of enthalpy/pressure drop in rotor to total stage drop
   • Expression R = delta_h_rotor / delta_h_stage
   • Values for impulse (0), Parsons (0.5) and reaction stages
2. 8 Marks
   bThe efficiency $\eta$ of a fan depends upon density $\rho$, Dynamic viscosity $\mu$ of the fluid, angular velocity $\omega$, diameter $D$ of the rotor and discharge $Q$. Express $\eta$ in terms of dimensionless parameters.
   How to answer

   • List variables: eta, rho, mu, omega, D, Q with dimensions
   • Apply Buckingham Pi theorem with repeating variables
   • Derive dimensionless groups e.g. Q/(omega D^3), rho omega D^2/mu, eta as function
3. 6 Marks
   aWhich is called Euler's equation for reaction turbine? What is Euler's energy equation?
   How to answer

   • State Euler's turbine equation for moment of momentum
   • Specialize for reaction turbine velocity triangles
   • State Euler's energy equation e = U*Vu change /g
4. 8 Marks
   bThe following particulars refers to a stage of a Parsons steam turbine comprising one ring of fixed blades and one ring of moving blades mean diameter of blade ring = 70 cm, RPM = 3000 rpm, steam velocity at exit from blades = 160 m/s, blade outlet angle = $20^{\circ}$, steam flow through blades = 7 kg/s. Draw the velocity diagram and find the following:

   1. i)Blade inlet angle
   2. ii)Tangential force on the ring of moving blades
   3. iii)Power developed in a stage
   How to answer

   • Calculate blade speed U = pi*D*N/60
   • Draw inlet and outlet velocity triangles for Parsons 50% reaction
   • Compute inlet angle, tangential force m*delta_Vw, power = F*U
5. 7 Marks
   aWhat is reheat factor? What causes the improvement in efficiency of multi stage turbine as compared with a single stage turbine with same stage efficiency?
   How to answer

   • Define reheat factor as ratio of cumulative stage drop to overall drop
   • Explain why RF >1 due to diverging constant pressure lines on h-s diagram
   • Relate multistage vs single stage efficiency improvement
6. 7 Marks
   bDescribe velocity and pressure compounding of steam turbine.
   How to answer

   • Define compounding need for high steam velocity
   • Explain velocity compounding with Curtis stage diagram
   • Explain pressure compounding with Rateau stages diagram
7. 7 Marks
   aWhat are the advantages of centrifugal pump over reciprocating pump? Explain in brief.
   How to answer

   • Compare construction, priming, maintenance
   • Higher discharge, uniform flow, compactness
   • Suitability for variable heads
8. 7 Marks
   bExplain the phenomenon of cavitation in water turbines.
   How to answer

   • Define cavitation as vapour bubble formation and collapse
   • Conditions at runner exit/draft tube low pressure
   • Effects: erosion, noise, efficiency drop and prevention
9. 8 Marks
   aA Pelton wheel is having a mean bucket diameter of 1 m and is running at 1000 rpm. The net head on the Pelton wheel is 700 m. If the side clearance angle is $15^{\circ}$ and discharge through nozzle is $0.1 \text{ m}^3/\text{s}$, find:

   1. i)Power available at the nozzle
   2. ii)Hydraulic efficiency of the turbine
   How to answer

   • Compute jet velocity V1 = sqrt(2gH) and bucket speed U
   • Power at nozzle = rho g H Q
   • Hydraulic efficiency = 2*(V1-U)*(1-cos beta)*U / V1^2
10. 6 Marks
    bDefine surging and efficiency of axial flow compressor.
    How to answer

    • Define surging as unstable flow reversal in compressor
    • Define axial compressor efficiency (isentropic/polytropic)
    • Mention effects of stall and surge line
11. 7 Marks
    aDescribe the Polytropic efficiency of compressor.
    How to answer

    • Define polytropic process with small stage efficiency
    • Derive relation eta_poly = n/(n-1) * (gamma-1)/gamma
    • Explain advantage over isentropic efficiency for multistage
12. 7 Marks
    bDraw the vector diagram of centrifugal compressor.
    How to answer

    • Show impeller inlet and outlet triangles
    • Label U, Vf, Vw, V components
    • Explain forward/radial/backward blading effect
13. 6 Marks
    aWrite down the application of power transmitting devices at industry level.
    How to answer

    • List fluid couplings, torque converters, belts, gears
    • Industrial uses: conveyors, pumps, machine tools
    • Advantages of smooth power transmission
14. 8 Marks
    bExplain working principle of fluid coupling with the help of a neat diagram.
    How to answer

    • Describe pump and turbine elements with oil circulation
    • Explain torque transmission without mechanical contact
    • Draw neat cross-section showing impeller and runner
15. 14 Marks
    Write short note on following- (Any Two):

    1. a)Centrifugal blower
    2. b)Hydraulic Intensifier
    3. c)Draft tube
    How to answer

    • Select any two topics with definition and construction
    • Explain working and applications
    • Add neat sketch and advantages/limitations