GATE AE (Aerospace Engineering) Aerothermodynamics & Cycles previous year questions from the Propulsion section, with figures and the official answer key where available.
Propulsion - Aerothermodynamics & Cycles
Which one of the following makes an ideal air-standard Stirling cycle?
Official answer: C
Propulsion - Aerothermodynamics & Cycles
The figure below depicts two ideal gas turbine cycles, cycle 1-2-3-4-1 and cycle 1-2-3'-4'-1, on a $T$-$s$ diagram. Which one of the following statements is FALSE?
Official answer: B
Propulsion - Aerothermodynamics & Cycles
A furnace of 250 MW rating is used to melt and raise the temperature of aluminium from 25 °C to 900 °C. Aluminium has a solid-state specific heat, latent heat, and liquid-state specific heat of 0.9 kJ/kg-K, 390 kJ/kg, and 1.108 kJ/kg-K, respectively, and the furnace has 70% efficiency. The melting point of aluminium is 660 °C. The amount of aluminium that can be processed per hour is ________ kg (rounded off to 1 decimal place).
Official answer: 513270.0 to 513272.0
Propulsion - Aerothermodynamics & Cycles
Air at temperature 300 K is compressed isentropically from a pressure of 1 bar to 10 bar in a compressor. Eighty percent of the compressed air is supplied to a combustor. In the combustor, 0.88 MJ of heat is added per kg of air. The specific heat at constant pressure is $C_p = 1005$ J/kg/K and the specific heat ratio is $\gamma = 1.4$. The temperature of the air leaving the combustor is ___ K (rounded off to one decimal place).
Official answer: 1454.0 to 1455.0
Propulsion - Aerothermodynamics & Cycles
For an ideal gas, the specific heat at constant pressure is 1147 J/kg K and the ratio of specific heats is equal to 1.33. What is the value of the gas constant for this gas in J/kg K?
Official answer: A
Propulsion - Aerothermodynamics & Cycles
In the figure shown below, various thermodynamics processes for an ideal gas are represented. Match each curve with the process that it best represents.
Official answer: C
Propulsion - Aerothermodynamics & Cycles
The first law of thermodynamics is also known as conservation of
Official answer: C
Propulsion - Aerothermodynamics & Cycles
In an ideal gas turbine cycle, the expansion in a turbine is represented by
Official answer: B
Propulsion - Aerothermodynamics & Cycles
The theoretical maximum velocity (in m/s) of air expanding from a reservoir at 700 K is __________ (accurate to two decimal places). Specific heat of air at constant pressure is 1005 J/(kg-K).
Official answer: 1185.00 to 1186.50
Propulsion - Aerothermodynamics & Cycles
A wall of thickness 5 mm is heated by a hot gas flowing along the wall. The gas is at a temperature of 3000 K, and the convective heat transfer coefficient is 160 W/m$^2$K. The wall thermal conductivity is 40 W/mK. If the colder side of the wall is held at 500 K, the temperature of the side exposed to the hot gas is _______ K.
Official answer: 548 to 550
Propulsion - Aerothermodynamics & Cycles
A substance experiences an entropy change of $\Delta s > 0$ in a quasi-steady process. The rise in temperature (corresponding to the entropy change $\Delta s$) is highest for the following process:
Official answer: C