GATE AE topic:engine-performance PYQs & Answers — Page 2

Questions 11–20 of 20. Imported answers require independent review unless marked reviewed.

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).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A twin-spool turbofan engine is operated at sea level (Pₐ = 1 bar, Tₐ = 288 K). The engine has separate cold and hot nozzles. During 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 (Cₚ) is 1.005 kJ/kg-K and the ratio of specific heats (γ) is 1.4 for air.

Assuming 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).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The air flow rate through the gas generator of a turboprop engine is 100 kg/s. The stagnation temperatures at 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 (Cₚ) 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)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The design flight Mach number of an ideal ramjet engine is 2.8. The stagnation temperature of air at the exit of the combustor is 2400 K. Assuming the specific heat ratio of 1.4 and gas constant of 287 J/(kg K), the velocity of air at the exit of the engine is ______ m/s (round off to one decimal place).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The propulsive efficiency of a ramjet engine is lower than that of a low bypass turbofan engine operating under the same conditions and producing the same thrust, primarily because the ramjet engine

Your answerChoose one option.

has larger kinetic energy lost in the exhaust jet.

has lower thrust power.

is not self-starting.

has higher thrust to weight ratio.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

While flying at Mach 2.0, 11 km altitude and producing the same thrust, what is the correct order from the lowest thrust specific fuel consumption (

) to the highest

Your answerChoose one option.

Turbofan, Ramjet, Turbojet

Turbofan, Turbojet, Ramjet

Ramjet, Turbojet, Turbofan

Turbojet, Turbofan, Ramjet

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

In a turbot engine, the compressor outlet temperature increases with decrease efficiency of the compressor. If the turbine inlet temperature remains constant, with decreasing efficiency of the compressor, the thrust specific fuel consumption of the engine

Your answerChoose one option.

decreases, as the heat input is lower.

remains unchanged.

increases, as the compressor needs more work input from the turbine.

decreases, as the thrust produced is higher.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An aircraft with a turbojet engine flies at a velocity of 100 m/s. If the jet exhaust velocity is 300 m/s, the propulsive efficiency of the engine, assuming a negligible fuel-air ratio, is

Your answerChoose one option.

0.33

0.50

0.67

0.80

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An aircraft with a turboprop engine produces a thrust of 500 N and flies at 100 m/s. If the propeller efficiency is 0.5, the shaft power produced by the engine is

Your answerChoose one option.

50 kW

100 kW

125 kW

500 kW

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An aircraft with a turbojet engine, having an inlet area of 1 m², is flying at 270 m/s at an altitude where the atmospheric pressure is equal to 0.9 bar and the ambient temperature is equal to 290 K. The stagnation pressure and temperature at the exit of the turbine are equal to 1.6 bar and 774 K respectively. The specific heat at constant pressure of the burned gases is equal to 1.147 kJ/kgK and the ratio of specific heats is equal to 1.33. Considering ideal expansion in the nozzle with no losses, the specific thrust produced by the engine is ________ Ns/kg (in one decimal place).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE AE topic:engine-performance PYQs

Question 43

Question 45

Question 48

Question 47

Question 10

Question 11

Question 29

Question 32

Question 33

Question 47