Gas turbine combustor - Propulsion - Aerospace Engineering Previous Year Questions

\(\delta Q\) and \(\delta W\) are the heat and work interactions of a system with its surroundings, and \(dU\) is the change in the internal energy of the system. For an adiabatic process in a closed, constant pressure combustor, which one of the following options is correct?

A gaseous fuel mixture comprising 3 moles of methane and 2 moles of ammonia is combusted in X moles of pure oxygen in stoichiometric amount. Assuming complete combustion, with only \(CO_2\), \(H_2O\) and \(N_2\) in the product gases, the value of X is ____.
\(3 CH_4 + 2 NH_3 + X O_2 \rightarrow \text{Products } (CO_2, H_2O, N_2)\)

A perfect gas flows through a frictionless constant-area duct with heat addition. The inlet conditions are as follows: pressure 100 kPa, density 1 kg/m³, and velocity 100 m/s. At a particular downstream location, the gas velocity is 200 m/s. The static pressure at the downstream location is ________ kPa (answer in integer).

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).

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 the following statements is FALSE?

Isobutane (\( C_4H_{10} \)) is burnt completely in pure oxygen as per the reaction given below. Given that the standard heats of formation (in kcal/mole) of isobutane, carbon dioxide, and water vapour are \( -31.489 \), \( -94.052 \), and \( -60.150 \), respectively, the heat of reaction is __________ kcal (rounded off to 2 decimal places).
\( C_4H_{10} + 6.5 O_2 \rightarrow 4 CO_2 + 5 H_2O \)