Thermodynamic Cycles of Gas Turbines

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

Which one of the following makes an ideal air-standard Stirling cycle?

Subtopic: Thrust Equations & Specific Fuel Consumption

For a given air-standard power, the propulsive efficiency of a turbofan engine is more than that of a turbojet engine. Which of the following is/are the reason(s) for this?

Subtopic: Thrust Equations & Specific Fuel Consumption

A furnace of 250 MW rating is used to melt and raise the temperature of aluminium from 25 oC to 900 oC. 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 oC. The amount of aluminium that can be processed per hour is ________ kg (rounded off to 1 decimal place).

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

An aircraft is flying at an altitude of 4500 m above sea level, where the ambient pressure, temperature and density are 57 kPa, 259 K and 0.777 kg/m^3, respectively. The speed of the aircraft (V) is 230 m/s. Gas constant R= 287 J/kg/K, and specific heat ratio $\gamma$ = 1.4. If the stagnation pressure is po, and static pressure is p, the value of [ po-p 1 2$\rho$V^2 ] is ________ (rounded off to two decimal places).

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

An ideal turbofan with a bypass ratio of 5 has core mass flow rate, ṁ a,c= 100 kg/s. The core and the fan exhausts are separate and optimally expanded. The core exhaust speed is 600 m/s and the fan exhaust speed is 120 m/s. If the fuel mass flow rate is negligible in comparison to ṁ a,c, the static specific thrust (T/ṁ a,c) developed by the engine is ____ Ns/kg (rounded off to the nearest integer).

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

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?

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

In the figure shown below, various thermodynamics processes for a n ideal gas are represented. Match each curve with the process that it best represents.

Subtopic: Thrust Equations & Specific Fuel Consumption

An aircraft with a turbojet engine is flying at 250 m/s. The uninstalled thrust produced by the engine is 60000 N. The heating value of the fuel is 44 × 10 6 J/kg. The engine has a thermal efficiency of 35% while burning the fuel at a rate of 3 kg/s. Assume the engine exit pressure to be equal to the ambient pressure. What is the propulsion efficiency of the engine under these conditions (in percentage)?

Subtopic: Thrust Equations & Specific Fuel Consumption

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

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

In a static test, a turbofan engine with bypass ratio of 9 has core hot exhaust speed 1.5 times that of fan exhaust speed. The engine is operated at a fuel to air ratio of f = 0.03. Both the fan and the core streams have no pressure thrust. The ratio of fan thrust to thrust from the core engine is _____ (round off to one decimal place).

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

The combustion process in a turboshaft engine during ideal Brayton cycle operation is considered to be:

Subtopic: Thrust Equations & Specific Fuel Consumption

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

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

One kg of diatomic gas is heated and its temperature increases from 100 K to 600 K. The energy added at constant pressure during this process is 500 kJ. The specific heat at constant volume for the gas is _________ kJ/(kg K) (round off to 2 decimal places).

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

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).

Subtopic: Thrust Equations & Specific Fuel Consumption

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

Subtopic: Thrust Equations & Specific Fuel Consumption

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

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

A turbojet engine is operating with afterburner off. If the afterburner is switched on, then

Subtopic: Turbojet, Turbofan & Turboprop Engine Performance

On which one of the following thermodynamic cycles does an ideal ramjet operate?