List of top Propulsion Questions on Fuels and Combustion asked in GATE Aerospace Engineering

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.

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 \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]
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 \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]
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 \_\_\_. \[ 3 \, {CH}_4 + 2 \, {NH}_3 + X \, {O}_2 \rightarrow {Products (CO}_2, \, {H}_2{O}, \, {N}_2{)} \]

A surrogate liquid hydrocarbon fuel, approximated as \( \mathrm{C}_{10}\mathrm{H}_{12} \), is burned with dry air (79% \( \mathrm{N_2} \) and 21% \( \mathrm{O_2} \) by volume). How many moles of dry air are required for the stoichiometric combustion of 1 mole of this fuel at atmospheric conditions?

A gas turbine combustor burns methane with air at equivalence ratio $\phi=0.5$, where $\displaystyle \phi=\frac{(F/A)}{(F/A)_{\text{st}}}$. If the air mass-flow rate is $\dot m_{\text{air}}=20\ \text{kg/s}$, find the methane mass-flow rate (kg/s). (round off to two decimal places)
A cryogenic liquid rocket engine (expander cycle) burns liquid hydrogen and liquid oxygen at stoichiometry. The hydrogen mass-flow rate is $\dot m_{H_2}=32\,\text{kg/s}$, and the oxygen mass-flow rate satisfies $\dot m_{O_2}/\dot m_{H_2}=8$. Assuming the forward reaction dominates, find the rate of formation of $\mathrm{H_2O}$ (kmol/s). (round off to the nearest integer)