Rockets - Propulsion - Aerospace Engineering Previous Year Questions

A monopropellant liquid rocket engine has 800 injectors of diameter 4 mm each, and with a discharge coefficient of 0.65. The liquid propellant of density 1000 kg/m³ flows through the injectors. There is a pressure difference of 10 bar across the injectors. The specific impulse of the rocket is 1500 m/s. The thrust generated by the rocket is ____ kN (rounded off to one decimal place).

An ideal ramjet with an optimally expanded exhaust is travelling at Mach 3. The ambient temperature and pressure are 260 K and 60 kPa, respectively. The inlet air mass flow rate is 50 kg/s. Exit temperature of the exhaust gases is 700 K. Fuel mass flow rate is negligible compared to air mass flow rate. Gas constant is \(R=287\) J/kg/K, and specific heat ratio is \(\gamma = 1.4\). The thrust generated by the engine is ____ kN (rounded off to one decimal place).

An ideal rocket has characteristic exhaust velocity of 1200 m/s, mass flow rate of 75 kg/s, thrust coefficient of 1.5, and nozzle throat area of 0.025 m². The chamber pressure in kPa and the specific impulse due to gravity in seconds are ______, respectively. Assume that the acceleration due to gravity is 9.8 m/s².

Consider a launch vehicle of mass 10 tons being launched vertically. The vehicle has 8 tons of propellant, which burns completely at a constant rate over 50 s. If the engine specific impulse is 250 s, and the acceleration due to gravity at sea level is \( g_0 \), the acceleration experienced by the vehicle at lift-off is ________.