Aerospace Engineering GATE 2021 Questions with Answer

Ques 1 Aerodynamics

To estimate aerodynamic loads on an aircraft flying at 100 km/h at standard sea-level conditions, a one-fifth scale model is tested in a variable-density wind tunnel ensuring similarity of inertial and viscous forces. The pressure used in the wind tunnel is 10 times the atmospheric pressure. Assuming the ideal gas law to hold and the same temperature conditions in model and prototype, the velocity needed in the wind tunnel test-section is _______.

Ques 2 Aerodynamics

A finite wing of elliptic planform with aspect ratio 10, whose section is a symmetric airfoil, is placed in a uniform flow at 5 degrees angle of attack. The induced drag coefficient for the wing is _______. (round off to three decimal places)

Ques 3 Aircraft Propulsion

A jet aircraft weighing 10,000 kg has an elliptic wing with a span of 10 m and area 30 m². The C_D0 for the aircraft is 0.025. The maximum speed of the aircraft in steady and level flight at sea level is 100 m/s. The density of air at sea level is 1.225 kg/m³ and take g = 10 m/s². The maximum thrust developed by the engine at sea level is _______ N. (round off to two decimal places)

Ques 4 Aircraft Propulsion

The combustion process in a turbo-shaft engine during ideal operation is: _______.

Ques 5 Aircraft Propulsion

How does the specific thrust of a turbojet engine change for a given flight speed with an increase in flight altitude?

Ques 6 Aircraft Propulsion

How does the propulsion efficiency of a turbofan engine, operating at a given Mach number and a given altitude, change with an increase in compressor pressure ratio?

Ques 7 Aircraft Propulsion

A solid propellant rocket producing 25 MN thrust is fired for 150 seconds. The specific impulse of the rocket is 2980 Ns/kg. How much propellant is burned during the rocket operation?

Ques 8 Aircraft Propulsion

An aircraft with a turbojet engine is flying at 270 m/s. The enthalpy of the incoming air at the intake is 260 kJ/kg and the enthalpy of the exhaust gases at the nozzle exit is 912 kJ/kg. The ratio of mass flow rates of fuel and air is equal to 0.019. The chemical energy (heating value) of fuel is 44.5 MJ/kg and the combustion process is ideal. The total loss of heat from the engine to the ambient is 25 kJ per kg of air. The velocity of the exhaust jet is _______ m/s. (round off to two decimal places)

Ques 9 Aircraft Propulsion

Hot gases are generated at a temperature of 2100 K and a pressure of 14 MPa in a rocket chamber. The hot gases are expanded ideally to the ambient pressure of 0.1 MPa in a convergent-divergent nozzle having a throat area of 0.1 m². The molecular mass of the gas is 22 kg/kmol. The ratio of specific heats (γ) of the gas is 1.32. The value of the universal gas constant (R_o) is 8314 J/kmol-K. The acceleration due to gravity, g, is 9.8 m/s². The specific impulse of the rocket is _______ seconds. (round off to two decimal places)

Ques 10 Aircraft Propulsion

A twin-spool turbofan engine is operated at sea level (P_a = 1 bar, T_a = 288 K).
The engine has separate cold and hot nozzles.
During the static thrust test at sea level, the overall mass flow rate of air through the engine and the cold exhaust temperature are measured to be 100 kg/s and 288 K, respectively.
The parameters for the engine are: Fan pressure ratio = 1.6, Overall pressure ratio = 20, Bypass ratio = 3.0, Turbine entry temperature = 1800 K. The specific heat at constant pressure (C_p) is 1.005 kJ/kg-K and the ratio of specific heats (γ) is 1.4 for air. Assuming an ideal fan and ideal expansion in the nozzle, the sea-level static thrust from the cold nozzle is _______ kN. (round off to two decimal places)

Ques 11 Aircraft Propulsion

At the design conditions, the velocity triangle at the mean radius of a single-stage axial compressor is such that the blade angle at the rotor exit is equal to 30°. The absolute velocities at the rotor inlet and exit are equal to 140 m/s and 240 m/s, respectively. The flow velocities relative to the rotor at the inlet and exit of the rotor are equal to 240 m/s and 140 m/s, respectively.

Ques 12 Aircraft Propulsion

A single-stage axial turbine has a mean blade speed of 340 m/s at the design condition with blade angles at the inlet and exit of the rotor being 21° and 55° respectively. The degree of reaction at the mean radius of the rotor is equal to 0.4. The annulus area at the rotor inlet is 0.08 m² and the density of gas at the rotor inlet is 0.9 kg/m³. The flow rate through the turbine at these conditions is _______ kg/s. (round off to two decimal places)

Ques 13 Aircraft Propulsion

The air flow rate through the gas generator of a turboprop engine is 100 kg/s. The stagnation temperatures at the inlet and exit of the combustor are 600 K and 1200 K, respectively. The burner efficiency is 90% and the heating value of the fuel is 40 MJ/kg. The specific heats at constant pressure (C_p) for air and burned gases are 1000 J/kg-K and 1200 J/kg-K, respectively. The flow rate of the fuel being used is _______ kg/s. (round off to two decimal places). (Note: Do not neglect the fuel flow rate with respect to the air flow rate)