ME-601 Thermal Engineering and Gas Dynamics - Jun 2026 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
   aDescribe the construction, working of Benson boiler and enlist its advantages and disadvantages.
   How to answer

   • Definition and type of Benson boiler as high-pressure once-through drumless boiler
   • Construction details - feed, economiser, radiant evaporator, superheater, no drum
   • Working with supercritical pressure and once-through flow steps
   • Advantages and disadvantages listed
2. 7 Marks
   bExplain boiler draught and discuss different types of draught systems used in boilers.
   How to answer

   • Meaning of boiler draught and its necessity
   • Natural vs artificial draught classification
   • Types: forced, induced, balanced, steam jet draught
   • Comparison of draught systems used in boilers
3. 7 Marks
   aDescribe the Rankine cycle and explain its working with the help of P-V and T-S diagram.
   How to answer

   • Four processes of Rankine cycle definition
   • P-V and T-S diagrams with labelling of pump, boiler, turbine, condenser
   • Working of each component in sequence
   • Efficiency expression and significance
4. 7 Marks
   bExplain the Binary-Vapor Cycle and discuss its applications in power generation.
   How to answer

   • Concept of binary-vapor cycle using two fluids
   • Arrangement of mercury/ topping and steam bottoming cycles
   • Working steps and T-S representation
   • Applications in power generation and advantages
5. 7 Marks
   aDerive the expression for the speed of sound in an ideal gas.
   How to answer

   • Assumptions for small isentropic pressure disturbance in ideal gas
   • Continuity and momentum equations across sound wave
   • Derivation to $a = \sqrt{\gamma R T}$
   • Dependence on temperature and gas properties
6. 7 Marks
   bA stream of air flows in a duct of 100 mm diameter at a rate of 1 kg/s. The stagnation temperature is $37^{\circ}C$. At one section of the duct the static pressure is 40 kPa. Calculate the Mach number, velocity, and stagnation pressure at this section.
   How to answer

   • Calculate flow area from 100 mm diameter and density from static state
   • Use mass flow $\dot m = \rho A V$ and isentropic stagnation relations
   • Solve for Mach number, then velocity $V = M a$
   • Find stagnation pressure $p_0/p$ relation
7. 14 Marks
   A two-stage air compressor with perfect intercooling takes in air at 1 bar pressure and $27^{\circ}C$. The law of compression in both the stages is $pv^{1.3} = \text{constant}$, the compressed air is delivered at 9 bar from the H.P. cylinder to an air receiver. Calculate, per kilogram of air,

   1. (i))The minimum work done
   2. (ii))The heat rejected to the intercooler
   How to answer

   • Given $p_1=1$ bar, $T_1=27^{\circ}C$, $p_2=9$ bar, $n=1.3$ with perfect intercooling
   • Intermediate pressure $p_i=\sqrt{p_1 p_2}$ for minimum work
   • Minimum work formula for two-stage with intercooler
   • Heat rejected in intercooler $= c_p(T_2-T_1)$ per kg
8. 7 Marks
   aDerive the conditions for maximum discharge in nozzles.
   How to answer

   • Mass flow and energy equations for nozzle flow
   • Condition $d\dot m/dp=0$ for maximum discharge
   • Critical pressure ratio derivation
   • Result for steam and ideal gas
9. 7 Marks
   bDiscuss the back pressure of steam condenser and its effect on power plant performance.
   How to answer

   • Definition of back pressure / condenser pressure
   • Effect on turbine work, cycle efficiency and heat rate
   • Limitations due to cooling water temperature and air leakage
   • Impact on power plant performance
10. 14 Marks
    Dry saturated steam at 6.5 bar with negligible velocity expands isentropically in a convergent divergent nozzle to 1.4 bar and dryness fraction of 0.95. Determine the final velocity of steam from the nozzle if 13% heat is lost in friction, find the % reduction in final velocity.
    How to answer

    • Obtain $h_1$ for dry saturated steam at 6.5 bar and $h_2$ at 1.4 bar, $x=0.95$ from steam tables
    • Isentropic velocity $V = \sqrt{2(h_1-h_2)}$
    • Apply 13% heat loss to get actual enthalpy drop and actual velocity
    • Compute % reduction in final velocity
11. 7 Marks
    aClassify the various types of air compressors.
    How to answer

    • Broad classification: reciprocating vs rotary vs dynamic
    • Positive displacement and turbo-compressors sub-types
    • Examples: axial, centrifugal, roots, vane, screw
    • Chart/diagram of classification
12. 7 Marks
    bExplain the effect of clearance volume on the performance of a reciprocating compressor.
    How to answer

    • Definition of clearance volume and clearance ratio
    • Effect on volumetric efficiency and work per cycle
    • Formula $\eta_v = 1+C-C r_p^{1/n}$ explanation
    • Performance implications for reciprocating compressor
13. 14 Marks
    Write short note on any **two**:

    1. (i))Cooling Towers
    2. (ii))Ash handling of thermal power plant
    3. (iii))Need for multistage compression
    4. (iv))Open and closed type of feed water heaters
    How to answer

    • Select any two topics from four given options
    • Give definition, construction/working and significance for each
    • Include neat sketch where applicable
    • Conclude with applications/advantages