List of top Propulsion Questions

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).

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).

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).

An ideal turbofan with a bypass ratio of 5 has core mass flow rate, \( \dot{m}_a,c = 100 \, {kg/s} \). 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 \( \dot{m}_a,c \), the static specific thrust (\( \frac{T}{\dot{m}_a,c} \)) developed by the engine is _________ Ns/kg (rounded off to the nearest integer).

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 \( {CO}_2 \), \( {H}_2{O} \), and \( {N}_2 \) in the product gases, the value of \( X \) is ____________. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]

An ideal two-stage rocket has identical specific impulse and structural coefficient for its two stages. For an optimized rocket, the two stages have identical payload ratio as well. The payload is 2 tons and the initial mass of the rocket is 200 tons. The mass of the second stage of the rocket (including the final payload mass) is ___________ tons.

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).
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 turbofan with a bypass ratio of 5 has core mass flow rate, \( \dot{m}_a,c = 100 \, {kg/s} \). 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 \( \dot{m}_a,c \), the static specific thrust (\( \frac{T}{\dot{m}_a,c} \)) developed by the engine is \_\_\_\_\_\_\_ Ns/kg (rounded off to the nearest integer).
An ideal two-stage rocket has identical specific impulse and structural coefficient for its two stages. For an optimized rocket, the two stages have identical payload ratio as well. The payload is 2 tons and the initial mass of the rocket is 200 tons. The mass of the second stage of the rocket (including the final payload mass) is \_\_\_\_ tons.
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 \( {CO}_2 \), \( {H}_2{O} \), and \( {N}_2 \) in the product gases, the value of \( X \) is \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]
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).
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 turbofan with a bypass ratio of 5 has core mass flow rate, \( \dot{m}_a,c = 100 \, {kg/s} \). 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 \( \dot{m}_a,c \), the static specific thrust (\( \frac{T}{\dot{m}_a,c} \)) developed by the engine is \_\_\_\_\_\_\_ Ns/kg (rounded off to the nearest integer).
An ideal two-stage rocket has identical specific impulse and structural coefficient for its two stages. For an optimized rocket, the two stages have identical payload ratio as well. The payload is 2 tons and the initial mass of the rocket is 200 tons. The mass of the second stage of the rocket (including the final payload mass) is \_\_\_\_ tons.
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 \( {CO}_2 \), \( {H}_2{O} \), and \( {N}_2 \) in the product gases, the value of \( X \) is \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]
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).
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 turbofan with a bypass ratio of 5 has core mass flow rate, \( \dot{m}_a,c = 100 \, {kg/s} \). 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 \( \dot{m}_a,c \), the static specific thrust (\( \frac{T}{\dot{m}_a,c} \)) developed by the engine is \_\_\_\_\_\_\_ Ns/kg (rounded off to the nearest integer).
An ideal two-stage rocket has identical specific impulse and structural coefficient for its two stages. For an optimized rocket, the two stages have identical payload ratio as well. The payload is 2 tons and the initial mass of the rocket is 200 tons. The mass of the second stage of the rocket (including the final payload mass) is \_\_\_\_ tons.
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 \( {CO}_2 \), \( {H}_2{O} \), and \( {N}_2 \) in the product gases, the value of \( X \) is \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]