Experimental Evaluation of Throttling Characteristics in a Radial Injector Pump‑Fed Rocket Engine

DOI

10.2991/978-94-6239-764-4_19How to use a DOI?

Keywords

Chamber pressure; Combustion Stability; Gas Generator Cycle; Mixture Ratio; Throttling

Abstract

Throttleable liquid rocket engines are essential for missions requiring precise thrust modulation, including planetary descent and reusable launch applications. This paper presents an experimental evaluation of throttling performance in a pump-fed liquid rocket engine operating on a gas-generator cycle with earth-storable hypergolic propellants and a radial injector configuration. Throttling capability was achieved through modifications to the command pressure circuitry and gas-generator fuel regulator. Two hot tests were conducted to assess engine operability across a reduced chamber-pressure envelope. In the first test, chamber pressure was reduced stepwise to 66.7% of nominal conditions before shutdown, while in the second test throttling was demonstrated down to 48.6% and again ramping up to 100% chamber pressure, demonstrating repeatability and dynamic control. Stable combustion was maintained throughout the throttle range, with chamber pressure roughness remaining below 0.2% of the mean value. Characteristic velocity efficiency remained approximately 93% over most of the throttling range. No nozzle flow separation, cavitation, or dynamic instability was observed. Gas-generator regulation and turbopump operation remained satisfactory. The results demonstrate robust and repeatable throttling performance in a radial-injector pump-fed engine operating with earth-storable propellants.

Copyright

© 2026 The Author(s)

Open Access

Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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TY  - CONF
AU  - Jatin Jangra
AU  - Rupesh Kumar Sinha
AU  - Chuna Ram
AU  - V. Siju
AU  - Mathew Saxon
AU  - Rajeev R. Krishnan
PY  - 2026
DA  - 2026/09/04
TI  - Experimental Evaluation of Throttling Characteristics in a Radial Injector Pump‑Fed Rocket Engine
BT  - Proceedings of the International Conference on Mechanics, Materials and Mechatronics (ICM³ 2026)
PB  - Atlantis Press
SP  - 226
EP  - 236
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6239-764-4_19
DO  - 10.2991/978-94-6239-764-4_19
ID  - Jangra2026
ER  -