ME-601 Thermal Engineering and Gas Dynamics - May 2022 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. 7 Marks
   aWhat is the fundamental difference between the operation of impulse and reaction steam turbines?
   How to answer

   • Define impulse turbine: pressure drop only in nozzles, constant pressure over moving blades
   • Define reaction turbine: pressure drop in fixed and moving blades
   • Compare blading, degree of reaction, efficiency and applications
2. 7 Marks
   bWhat is Steam Turbine? Explain boiler efficiency and equivalent evaporation in detail.
   How to answer

   • Define steam turbine and its principle
   • Define boiler efficiency with heat input-output formula
   • Define equivalent evaporation from and at 100C
   • Explain measurement procedure and significance
3. 7 Marks
   aDescribe Rankine cycle in detail.
   How to answer

   • List four processes of Rankine cycle
   • Explain pump, boiler, turbine, condenser working
   • Draw T-s and h-s diagrams
   • State assumptions and applications
4. 7 Marks
   bFind out the expression for Rankine cycle efficiency.
   How to answer

   • Write energy balance for boiler, turbine, pump, condenser
   • Express net work and heat supplied using enthalpies
   • Derive efficiency = (W_turbine - W_pump)/Q_supplied
   • Discuss effect of superheat and pressure
5. 7 Marks
   aDifferentiate between regenerative and reheat Rankine cycle with TS diagram.
   How to answer

   • Define reheat Rankine cycle and its layout
   • Define regenerative Rankine cycle with feedwater heaters
   • Compare on efficiency, moisture, work output
   • Show both on T-S diagram
6. 7 Marks
   bWhat is Mach number?
   How to answer

   • Define Mach number as ratio of flow velocity to sonic velocity
   • Give formula $M = V/a$
   • Explain compressible flow significance
   • State subsonic, sonic, supersonic ranges
7. 7 Marks
   aDescribe its (Mach Number) different values for which body is said to be supersonic and hypersonic speed.
   How to answer

   • Define Mach number regimes
   • State supersonic range $M>1$ typically 1 to 5
   • State hypersonic range $M>5$
   • Explain flow features in each regime
8. 7 Marks
   bExplain binary vapour cycle in detail.
   How to answer

   • Define binary vapour cycle concept using two fluids
   • Explain mercury-steam or topping-bottoming arrangement
   • Draw schematic and T-s diagram
   • List advantages and applications
9. 7 Marks
   aClassify the various types of air compressors.
   How to answer

   • Define positive displacement vs dynamic compressors
   • Classify reciprocating, rotary, centrifugal, axial
   • Draw classification chart
   • Give examples of each type
10. 7 Marks
    bWhat are the advantages of multi stage compression with internal cooling over single stage compression for the same pressure ratio?
    How to answer

    • Explain intercooling between stages
    • Show work saving on p-V diagram
    • List advantages: less work, better efficiency, lower temperature
    • Compare with single stage for same pressure ratio
11. 7 Marks
    aExplain double acting compressor.
    How to answer

    • Define double acting reciprocating compressor
    • Explain suction-compression on both sides of piston
    • Describe construction with piston rod and valves
    • State applications and advantages
12. 7 Marks
    bDefine nozzle efficiency and critical pressure ratio.
    How to answer

    • Define nozzle efficiency as actual to isentropic kinetic energy
    • Define critical pressure ratio for maximum mass flow
    • Give formulas for both
    • Explain significance in nozzle design
13. 7 Marks
    aExplain the need of compounding in steam turbines.
    How to answer

    • Explain high steam velocity and rotor speed problem
    • Define compounding to reduce speed in stages
    • Describe velocity, pressure and pressure-velocity compounding
    • State advantages for efficiency and blade stress
14. 7 Marks
    bWhat are the differences between supersaturated flow and isentropic flow through steam nozzles?
    How to answer

    • Define supersaturated vs equilibrium isentropic flow
    • Compare density, mass flow, velocity and dryness
    • Explain Wilson line and delayed condensation
    • Tabulate differences
15. 7 Marks
    aWhat are the conditions that produce super saturation of steam in nozzles?
    How to answer

    • Define supersaturation in convergent-divergent nozzle
    • List conditions: rapid expansion, absence of nuclei, high velocity
    • Explain crossing Wilson line without condensation
    • State effect on mass flow and pressure
16. 7 Marks
    bHow the condition of steam will effect the efficiency of Rankine Cycle?
    How to answer

    • Explain effect of pressure, superheat and moisture
    • Show efficiency increases with superheat and pressure
    • Explain moisture loss in turbine
    • Conclude optimum steam condition