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| Main Author: | |
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| Format: | Recurso digital |
| Language: | English |
| Published: |
Zenodo
2025
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| Subjects: | |
| Online Access: | https://doi.org/10.5281/zenodo.17771692 |
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Table of Contents:
- <p>Rocket nozzles are traditionally designed with a fixed expansion ratio, which allows optimal performance <br>only at a specific ambient pressure. During atmospheric ascent, however, the ambient pressure decreases continuously, <br>causing a fixed-geometry nozzle to operate under off-design conditions for a large portion of the flight. This results in <br>performance losses due to overexpansion or under expansion of the exhaust flow. To address this limitation, the present <br>work focuses on the theoretical performance analysis of a variable exit-area rocket nozzle capable of adapting its <br>expansion ratio to changing altitude conditions. A quasi-one-dimensional, steady, and isentropic flow model is <br>employed to describe the gas dynamics within a convergent–divergent nozzle with a fixed throat area and variable exit <br>area. Using established gas-dynamic relations, key performance parameters such as exit Mach number, exit pressure, <br>thrust, and thrust coefficient are evaluated for multiple exit area ratios over a range of ambient pressures representative <br>of different altitudes. The results are used to compare the performance of variable exit-area configurations with that <br>of a conventional fixed nozzle. The analysis highlights the potential of variable exit-area nozzles to achieve improved <br>thrust efficiency over a wider operating envelope. The identified trends provide useful theoretical insight into altitude<br>adaptive nozzle design and establish a foundation for future validation through computational fluid dynamics and <br>experimental studies.</p>