Numerical Study on Pyrolysis and Combustion Characteristics of Grain in Solid Fuel Ramjets

Eunchong Kim; Iksoo Park; Seongjoo Han; Jaehoon Ryu; Hyung Sub Sim

doi:10.6108/KSPE.2025.29.2.034

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2025 Vol.29, Issue 2 Preview Page Next Page

RESEARCH PAPERS

Numerical Study on Pyrolysis and Combustion Characteristics of Grain in Solid Fuel Ramjets 고체연료 램제트용 그레인의 열분해 및 연소 특성에 관한 수치해석 연구

30 April 2025. pp. 34-44

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Abstract

The solid fuel ramjet (SFRJ) is attracting attention due to its advantages, including high specific impulse, relative design simplicity, and improved combustion stability. This study investigates solid fuel pyrolysis and combustion using a commercial computational fluid dynamics program. Various reaction models and pyrolysis boundary conditions were evaluated, and the simulation results were compared against experimental data from the literature. Additionally, the effects of different air inlet mass flow rates and temperatures were examined using the reaction model and boundary condition that provided the best match with experimental data. Simulations were performed using the eddy dissipation model (EDM) and non-premixed combustion model (NPCM) under the assumption of complete fuel decomposition, applying mass flow inlet and wall+source conditions. The results indicated that the NPCM, particularly when coupled with the wall+source boundary condition, closely matched experimental data, yielding mean relative errors of 1.9% for outer boundary regions and 9.8% for temperatures. Parametric simulations further revealed a higher CO mass fraction in the premixed region and a subsequent rise in CO₂ mass fraction downstream as combustion progressed. These findings provide valuable insights for optimizing the design and performance of solid fuel ramjets, particularly in terms of enhancing fuel efficiency and combustion stability.

Keywords

Solid Fuel Ramjet

Computational Fluid Dynamics

Reaction Model

Boundary Condition

최근 고체연료 램제트 엔진(solid fuel ramjet, SFRJ)은 높은 비추력, 단순한 구조, 그리고 연소 안정성 등 여러 장점으로 인해 다시 주목받고 있다. 본 연구에서는 상용 전산유체역학 소프트웨어를 사용하여 고체연료의 열분해 및 연소 거동에 대한 반응 유동 해석을 수행하였다. 다양한 반응 모델과 연료 표면에서의 열분해 경계 조건을 평가하고, 시뮬레이션 결과를 선행 연구의 실험 결과와 비교 분석하였다. 또한, 실험 데이터와 가장 일치하는 반응 모델 및 경계 조건을 적용하여 흡입구 공기 질량 유량과 온도의 변화가 미치는 영향을 확인하였다. 이를 위해 eddy dissipation model(EDM)과 non-premixed combustion model(NPCM) 두 가지 반응 모델을 사용하였다. 고체연료의 열분해 과정은 연료가 완전히 분해되어 기체상으로 연소기에 주입된다는 가정하에 시뮬레이션을 수행하였으며, 이를 질량유량입구와 벽+소스 경계 조건을 사용하여 모델링하였다. 해석 결과, NPCM과 벽+소스 경계 조건을 적용한 경우 EDM보다 실험 데이터와 더 높은 일치도를 보였다. 특히, NPCM과 벽+소스 조건을 적용했을 때 외부 영역 경계의 y축 방향 확장 거리는 실험결과와 비교하여 평균 상대 오차율이 약 1.9%, 온도 예측에서는 약 9.8%로 분석되었다. 매개변수 해석 결과, 공기의 질량 유속과 온도가 증가할수록, 예혼합 영역에서 CO의 질량 분율이 증가하는 경향을 보였으며, 연소가 진행됨에 따라 예혼합 영역 하류에서 CO₂의 질량 분율 또한 증가하는 것으로 확인되었다. 이러한 연구 결과는 향후 고체연료 램제트의 설계 및 성능 최적화, 특히 연료 효율성과 연소 안정성 향상에 유용한 정보를 제공할 수 있다.

키워드

고체연료 램제트

전산유체역학

반응 모델

경계 조건

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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 : 29
No :2
Pages :34-44
Received Date : 2024-12-16
Revised Date : 2025-02-07
Accepted Date : 2025-02-13
DOI :https://doi.org/10.6108/KSPE.2025.29.2.034

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

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