旋转爆震三维非预混混合特性及流场结构研究

Numerical Study of Mixing and Flow Field Characteristics ona Three-Dimensional Non-Premixed Rotating Detonation

关键词:  旋转爆震发动机  非预混数值模拟  流场结构  混合特性

Key words:  Rotating detonation engine  Non-premixed numerical simulation  Flow field characristics  Mixing performance

摘要:

为深入研究旋转爆震三维非预混流场结构，基于7组分8步反应的化学反应模型，开展了H2/Air旋转爆震流场的数值模拟研究，计算中考虑了黏性的影响。计算结果表明:该喷注结构在冷流流场中混合效果较好，能够在较短距离内实现燃料和氧化剂的充分混合，但起爆后燃烧室内形成的高压环境使得外壁面附近来流可燃气难以到达，可燃气体层主要靠近燃烧室内壁面；旋转爆震波沿燃烧室内壁面周向传播，爆震波后沿径向和周向方向形成“双诱导激波”结构，并进一步导致爆震波后出现高温区和高压区“不吻合”的流场现象；在燃烧室入口截面，爆震波后形成“三诱导激波”结构，诱导激波通过空气环缝向上游传播并对来流燃料和氧化剂的喷注产生影响。

Abstract:

In order to analyse the flow field characteristics of non-premixed rotating detonation combustor， based on 7-species 8-step hydrogen-air chemical reaction mechanism， three-dimensional numerical simulation was performed with viscous effect. The numerical results show that in the non-reaction flow field， H2 and air are well blended within a quite short distance. While in the detonation flow field， fresh hydrogen mainly concerntrated near the inner wall because of the high combustor pressure， thus resulting in the rotating detonation wave located near the inner wall. In the combustor， two induced shock waves are obversed in circumferential and radial directions behind the detonation wave， the highest pressure/temperature zones after the detonation wave are mismatching. At the head of the combustor， three induced waves are observed and the injection of the hydrogen/air are effected by the detonation wave via the upstream induced shock wave.