高马赫气流中双排横向喷注燃料增混方法数值研究  

Numerical study on method of fuel enhancing mixing with dual-row transverse injection in high Mach number airflow

作　　者：周越寰 张旭[2] 黄庭隆 于德海 岳连捷[2] 孙波[1] ZHOU Yuehuan;ZHANG Xu;HUANG Tinglong;YU Dehai;YUE Lianjie;SUN Bo(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;State Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;Beijing System Design Institute of Mechanical-Electrical Engineering,Beijing 100039,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094 [2]中国科学院力学研究所高温气体动力学国家重点实验室,北京100190 [3]北京机电工程总体设计部,北京100039

出　　处：《推进技术》2025年第3期173-182,共10页Journal of Propulsion Technology

基　　金：国家自然科学基金(U2141220,12302392,52006001)。

摘　　要：针对高马赫数燃烧室的掺混难题,本文数值研究了入口马赫数4.08条件下流向孔间距、当量比和喷注总压对双排氢燃料喷注掺混规律的影响。相比以往研究仅发现极近流向孔间距有利于近场掺混,本文进一步发现25~70倍孔径的较远流向孔间距能够改善远场掺混,且最佳间距与当量比和喷注总压有关,其对应掺混增益范围为1.16~1.25。给定当量比和孔间距条件下,合理设置喷注总压能进一步改善远场掺混,使掺混增益达1.29。通过剖析流场结构,揭示了双排喷注增强掺混的两种机制,分别与弓形激波等因素降低上游喷注尾迹区的静压和动压相关。其一,较近流向孔间距时,上游喷注尾迹区低静压意味着下游喷注反压比提高,促进下游喷注诱导流动分离,有利于喷孔近场掺混。其二,较远流向孔间距时,上游喷注尾迹区低动压意味着下游喷注动量比提高,能改善下游喷注射流穿透深度,有利于下游远场掺混。实际掺混过程中,总掺混增益是两种机制耦合作用的结果,最佳间距取决于当量比和喷注压力。Aiming for the challenges of fuel-air mixing in high Mach number combustion chamber,the work focuses on the effects of streamwise orifice spacing,equivalence ratio,and injection total pressure on the dual-row hydrogen fuel injection mixing pattern under an air inflow Mach number of 4.08.Existing literature has suggested that extremely close orifice spacing is favorable for near-field mixing near the injector.Furthermore,this study found that orifice spacing between 25 to 70 times the diameter enhances downstream mixing and thus helps improve combustion performance.The optimal spacing is found to be related to the equivalence ratio and in⁃jection total pressure,with the corresponding mixing enhancement ranging from 1.16 to 1.25.Under given equiva⁃lence ratios and orifice spacing conditions,appropriately setting the injection total pressure can further enhance far-field mixing,achieving a mixing gain of 1.29.By analyzing the flow field structure,two mechanisms enhanc⁃ing mixing with dual injection are unveiled,each related to reducing static pressure and dynamic pressure in the upstream injection wake zone through factors such as bow shock waves.On the one hand,at relatively close streamwise orifice spacing,the low static pressure in the upstream injection wake zone implies an increased back pressure ratio for the downstream injection,promoting induced flow separation for the downstream injection,thus benefiting near-field mixing.On the other hand,at relatively far streamwise orifice spacing,the low dynamic pressure in the upstream injection wake zone implies an increased momentum ratio for the downstream injection,which can improve the penetration depth of the downstream injection jet flow,favoring far-field mixing down⁃stream.In the actual mixing process,the total mixing enhancement is a result of the coupling of these two mecha⁃nisms,and the optimal spacings depend on the equivalence ratios and injection pressures.

关 键 词：超燃冲压发动机 横向射流 双排喷注 增混方法 远场掺混 

分 类 号：V231.2[航空宇航科学与技术—航空宇航推进理论与工程]