斜爆轰发动机燃烧机理试验研究

Experimental Research on Combustion Mechanism of Oblique Detonation Engines

关键词:  斜爆轰发动机  超声速燃烧  激波诱导燃烧  斜爆轰波  斜激波

Key words:  Oblique detonation engines  Supersonic combustion  Shock-induced combustion  Oblique detonation wave  Oblique shock wave

摘要:

为了研究斜爆轰发动机的稳定燃烧机理，开展了飞行马赫数9的斜爆轰发动机的数值模拟研究和试验研究。设计了全尺度斜爆轰发动机模型，发动机的总长度为2.8m。采用两级进气道压缩，每级压缩角度均为15°。利用三个小支板在进气道前缘主流核心区中进行氢气的喷射和混合。采用带化学反应的雷诺平均N-S方程、SST k-ω模型以及9组分19步反应的基元反应模型，对氢气混合过程和发动机燃烧过程进行了数值模拟研究。结果表明，氢气在进气道内混合得比较均匀，在燃烧室内获得了稳定的斜爆轰流场和正爆轰流场。在激波风洞中开展了马赫数9状态下的斜爆轰发动机稳定燃烧机理试验研究，在50ms的风洞有效试验时间内获得了持续稳定的斜爆轰流场，试验结果与数值模拟结果吻合较好，表明在试验中形成了斜爆轰波。研究结果证明了斜爆轰发动机的技术可行性。

Abstract:

Numerical simulations and experiments of a Ma 9 oblique detonation engine were conducted to study the combustion mechanism of oblique detonation engines. Firstly， a full-scale engine model with a length of 2.8m was designed. The engine inlet is a two-stage compression inlet composed of two 15°-inclined ramps. The hydrogen is pre-injected into the main flow at the leading front of the inlet by three strut-injectors. Secondly， the mixing process at the inlet and the combustion process in the combustor were numerically simulated. In the numerical simulations， the governing equations are Reynolds average Navier-Stokes equations with SST k-ω turbulence model and 9-species and 19-recations detailed chemical reaction kinetics. The numerical results show that the mixing process of hydrogen along the inlet is good. The stable oblique detonation waves and normal detonation waves are obtained in the combustor. Finally， the experiments under Ma 9 flight conditions were conducted in the shock tunnel. The stable flow fields of oblique detonation engine were established in the duration of 50ms test time of the shock tunnel. The experimental results are in good agreements with numerical results which means that stable oblique detonation waves were successfully obtained in the shock tunnel experiments. This research results demonstrate the technical feasibility of oblique detonation engines.