Aerospace Engineering GATE 2023 Questions with Answer

Ques 1 Aerodynamics

The figures shown in the options are schematics of airfoil shapes (not to scale). For a civilian transport aircraft designed for a cruise Mach number of 0.8, which among them is aerodynamically best suited as a wing section?

A

B

C

D

Ques 2 Aerodynamics

Consider the International Standard Atmosphere (ISA) with h being the geopotential altitude (in km) and dT/dh being the temperature gradient (in K/m). Which of the following combination(s) of (h, dT/dh) is/are as per ISA?

Ques 3 Aerodynamics

For an airfoil, which of the relations given about the critical Mach number M_cr and drag divergence Mach number M_dd is/are correct?

Ques 4 Aerodynamics

A thin cambered airfoil has lift coefficient c_l = 0 at an angle of attack α = -1.1°. Assuming that stall occurs at much larger α, the c_l at α = 4° is _______. (round off to two decimal places)

Ques 5 Aircraft Propulsion

In a single-spool aviation turbojet engine, which of the following is the correct relationship between the total work output W_T of a 2-stage axial turbine and the total work required W_c by a 6-stage axial compressor, neglecting losses?

Ques 6 Aircraft Propulsion

For a stage of a 50% reaction ideal axial flow compressor (symmetrical blading), select the correct statement from the options given.

Ques 7 Aircraft Propulsion

An aircraft is cruising with a forward speed V_a and the jet exhaust speed relative to the engine at the exit is V_j. If V_j/V_a = 2, what is the propulsive efficiency?

Ques 8 Aircraft Propulsion

From the options given, select all that are true for turbofan engines with afterburners.

Ques 9 Aircraft Propulsion

A supersonic vehicle powered by a ramjet engine is cruising at a speed of 1000 m/s. The ramjet engine burns hydrogen in a subsonic combustor to produce thrust. The heat of combustion for hydrogen is 120 MJ/kg. The overall efficiency of the engine η_o, defined as the ratio of propulsive power to the total heat release in the combustor, is 40%. Taking acceleration due to gravity g₀ = 10 m/s², the specific impulse of the engine is _______ seconds. (round off to the nearest integer)

Ques 10 Aircraft Propulsion

Two missiles A and B powered by solid rocket motors have identical specific impulse, liftoff mass of 5600 kg each, and burn durations of t_A = 30 s and t_B = 70 s respectively. The propellant mass flow rates, ṁ_A and ṁ_B for missiles A and B, respectively, are given by ṁ_A = 120 kg/s, 0 ≤ t ≤ 30 and ṁ_B = 70 kg/s, 0 ≤ t ≤ 70. Neglecting gravity and aerodynamic forces, the relationship between the final velocities V_A and V_B of missiles A and B, respectively, is given by

Ques 11 Aircraft Propulsion

A scramjet engine features an intake, isolator, combustor, and a nozzle, as shown in the schematic. Station 3 indicates the combustor entry point. Assume stagnation enthalpy to be constant between Stations 1 and 3, and air to be a calorically perfect gas with specific heat ratio γ. Select the correct expression for Mach number M₃ at the inlet to the combustor from the options given.

A

B

C

D

Ques 12 Aircraft Propulsion

A gas turbine combustor is burning methane and air at an equivalence ratio φ = (F/A)/(F/A)_stoich, where φ = 0.5 and (F/A)_stoich is the ratio of the mass flow rate of fuel to the mass flow rate of air at stoichiometry. If the air flow rate is ṁ_air = 20 kg/s, then the mass flow rate of methane is _______ kg/s. (round off to two decimal places)

Ques 13 Aircraft Propulsion

A centrifugal air compressor has an inlet root diameter of 0.25 m and the outlet diameter of the impeller is 0.6 m. The pressure ratio is 5.0. The air at the inlet of the rotor is at 1 atm and 25 °C. The polytropic efficiency is 0.8 and the slip factor is 0.92. Use C_p = 1.004 kJ/kg-K and γ = 1.4. The impeller speed in revolutions per minute (RPM) is _______. (round off to the nearest integer)