高马赫数飞行条件下超燃冲压发动机燃烧组织方案数值模拟

Numerical simulation on combustion organization scheme of scramjet at high Mach number

针对高马赫数飞行条件下(Ma=8,其中燃烧室内流马赫数为3.88)超燃冲压发动机燃烧组织方案的优化问题,采用三维可压缩雷诺平均(RANS)数值模拟方法对采用不同燃料喷射角度和凹腔后倾角的燃烧方案进行了数值模拟研究。结果表明:高马赫数下燃烧主要集中在凹腔和燃烧室近壁区,随着燃料喷射角度的增大,燃烧反应更加剧烈;增大燃料喷射角度和减小凹腔后倾角能提高混合效率,从而提高燃烧效率,燃烧也更充分,但是燃烧引起的总压损失也会相应地提高;高马赫数条件下发动机内流阻力很大,大约是发动机净推力的7~8倍,而增大喷射角度和减小凹腔后倾角有利于提高发动机的推力性能,其中采用135°的逆向燃料喷入方案获得的正推力最大,此时燃烧位置相对靠前,有利于燃烧室设计尺寸的小型化。

Aiming at the optimization problem of combustion organization scheme for the scramjet engine under high Mach number conditions(Ma=8,where the Mach number in the combustor is 3.88),a numerical simulation method with three-dimensional steady compressible RANS was used to study the combustion scheme with different injection angles and cavity angles.The results indicat that the combustion at high Mach numbers occurs mainly in the cavity and near-wall area of the combustor,and the combustion reaction becomes more intense with the increase of injection angle.Greater injection angles and smaller cavity angles not only lead to higher mixing efficiency and more efficient combustion,but also increase the total pressure loss due to combustion.Under high Mach number conditions,the engine flow resistance is high,which is 7-8 times of the total thrust,and increasing the injection angle and reducing the cavity angle are beneficial for improving the engine performance.Among them,the positive thrust achieved by using a 135°reverse fuel injection is the highest,and the combustion position is relatively forward,which is conducive to the miniaturization of combustor design size.