GATE 2022 AE – Question 23
The region of highest static temperature in a rocket engine and the region of highest heat flux are ____________, respectively.
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Correct answer: (B) combustion chamber and nozzle throat
Explanation
In a liquid or solid rocket engine the temperature and the heat flux peak in different places.
- **Highest static temperature: the combustion chamber.** The chemical energy is released there and the gas is nearly at rest (low velocity), so the static temperature is close to the stagnation (flame) temperature. In the nozzle the gas expands and its static temperature falls.
- **Highest heat flux: the nozzle throat.** At the throat the gas velocity and mass flux are the highest per unit area ($M=1$), so the convective heat-transfer coefficient is the largest. Together with the high gas temperature, this gives the highest heat flux into the wall.
Answer **combustion chamber and nozzle throat** (B).