Effects of injector geometry on the combustion characteristics and stability of nonpremixed O2/CH4 coaxial flames in a model combustor

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology Pub Date : 2025-04-08 DOI:10.1016/j.ast.2025.110205

Young Hoo Kim, Tae Won Kim, Ju Han Kim, Hyeon Woo Lee, Jae Hyun Kim, Oh Chae Kwon

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引用次数: 0

Abstract

Effects of injector diameter and lip thickness (t_L) on the combustion characteristics and stability of oxygen (O₂) and methane (CH₄) which is more suitable for reusable rockets are experimentally investigated considering nonpremixed O₂/CH₄ coaxial jet flames in a model combustor through their visualization with varying Reynolds number (Re). Increasing Re exhibits two different flame behaviors: stably attached and oscillating near-blowout flames. In the case that t_L is too small compared to the reaction region near the injector lip, the flame base is tremendously affected by the injected flow so that flame detachment occurs at low injection velocity; however, increasing t_L increases heat losses to the injector plate so that the optimal t_L is necessary to ensure the stably attached flames. At given oxygen-to-fuel mass ratio, the variation in the injector diameter also significantly affects the combustion stability limits due to the change of flow characteristics in the wake region behind the injector lip. A regime diagram of combustion stability is introduced using the effective Reynolds number Re_eff and a newly suggested parameter which is based on Re_eff and the fuel-injector diameter. The parameter is found to be useful to represent the injection conditions of the flame detachment and local flame extinction for the present injectors.

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喷油器几何形状对模型燃烧室中非预混O2/CH4同轴火焰燃烧特性和稳定性的影响

实验研究了喷射器直径和唇口厚度（tL）对氧气（O2）和甲烷（CH4）燃烧特性和稳定性的影响，后者更适用于可重复使用火箭。增加雷诺数会表现出两种不同的火焰行为：稳定的附着火焰和振荡的近吹火焰。与喷射器唇部附近的反应区域相比，tL 太小时，火焰底部会受到喷射流的巨大影响，因此火焰会在低喷射速度下脱离；然而，增加 tL 会增加喷射器板的热损失，因此需要最佳的 tL 来确保火焰的稳定附着。在给定的氧气与燃料质量比条件下，喷射器直径的变化也会显著影响燃烧稳定性极限，这是因为喷射器唇缘后的尾流区的流动特性发生了变化。利用有效雷诺数 Reeff 和一个基于 Reeff 和喷油器直径的新建议参数，引入了燃烧稳定性制度图。研究发现，该参数可用于表示目前喷油器火焰脱离和局部火焰熄灭的喷射条件。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Aerospace Science and Technology 工程技术-工程：宇航

CiteScore

10.30

自引率

28.60%

发文量

654

审稿时长

54 days

期刊介绍： Aerospace Science and Technology publishes articles of outstanding scientific quality. Each article is reviewed by two referees. The journal welcomes papers from a wide range of countries. This journal publishes original papers, review articles and short communications related to all fields of aerospace research, fundamental and applied, potential applications of which are clearly related to: • The design and the manufacture of aircraft, helicopters, missiles, launchers and satellites • The control of their environment • The study of various systems they are involved in, as supports or as targets. Authors are invited to submit papers on new advances in the following topics to aerospace applications: • Fluid dynamics • Energetics and propulsion • Materials and structures • Flight mechanics • Navigation, guidance and control • Acoustics • Optics • Electromagnetism and radar • Signal and image processing • Information processing • Data fusion • Decision aid • Human behaviour • Robotics and intelligent systems • Complex system engineering. Etc.