A Numerical Study on the Ramjet/Scramjet Mode Transition of an RBCC Engine according to Embedded Rocket Chamber Pressure Regulation

Sangwon Lim; Sang Hun Kang

doi:10.6108/KSPE.2026.30.5.012

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2026 Vol.30, Issue 5 Preview Page Next Page

RESEARCH PAPERS

A Numerical Study on the Ramjet/Scramjet Mode Transition of an RBCC Engine according to Embedded Rocket Chamber Pressure Regulation 임베디드 로켓의 챔버 압력 조절에 따른 RBCC 엔진의 램제트/스크램제트 모드 천이 전산 해석 연구

31 October 2026. pp. 12-22

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Abstract

To ensure stable mode transition of Rocket-Based Combined Cycle (RBCC) engines, precise control of thermal choking and inlet unstart occurring during transition is essential. This study proposes a strategy of regulating only the chamber pressure of the embedded rocket without variable geometry mechanisms and investigates mode transition characteristics through three-dimensional numerical analysis. As a result of sequential analyses for flight Mach numbers ranging from 3 to 6, it was confirmed that appropriately decreasing the chamber pressure of the embedded rocket as flight speed increases controls heat addition, thereby enabling stable transition to the ESJ mode. Finally, the mode-transition boundary, where the occurrence of thermal choking is determined by the rocket operating pressure, was identified at flight Mach 4.25.

Keywords

Rocket-Based Combined Cycle

Embedded Rocket

Mode Transition

Thermal Choking

로켓 기반 복합 사이클(RBCC) 엔진의 안정적인 모드 천이를 위해서는 천이 시 발생하는 열 질식 및 흡입구 불시동에 대한 정밀 제어가 필수적이다. 본 연구에서는 가변 형상 기구 없이 임베디드 로켓의 챔버 압력만을 조절하는 전략을 제안하고, 3차원 전산 해석을 통해 모드 천이 특성을 규명하였다. 비행 마하수 3에서 6 사이의 영역을 대상으로 순차적 해석을 수행한 결과, 비행 속도가 증가함에 따라 임베디드 로켓의 챔버 압력을 적절히 하향 조정하여 열 방출량을 제어하는 것이 ESJ 모드를 안정적으로 유도함을 확인하였다. 최종적으로 비행 마하수 4.25 조건에서 로켓 작동 압력에 따라 열 질식 발생 여부가 결정되는 모드 천이의 경계 지점을 식별하였다.

키워드

로켓 기반 복합 사이클

임베디드 로켓

모드 천이

열 질식

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Information

Publisher :The Korean Society of Propulsion Engineers
Publisher(Ko) :한국추진공학회
Journal Title :Journal of the Korean Society of Propulsion Engineers
Journal Title(Ko) :한국추진공학회지
Volume : 30
No :5
Pages :12-22
Received Date : 2026-02-23
Revised Date : 2026-04-20
Accepted Date : 2026-07-29
DOI :https://doi.org/10.6108/KSPE.2026.30.5.012

Journal of the Korean Society of Propulsion Engineers ISSN:1226-6027(Print) 2288-4548(Online) 한국추진공학회지

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