后台阶喷氢加喷空气超音速燃烧数值模拟

 为了提高带有后向台阶的超音速燃烧室的燃烧效率,提出了一种在氢气喷嘴后加一个空气喷嘴的方法,并且采用雷诺应力湍流模型和有限速率化学动力学模型对这种方法进行了数值模拟研究。计算结果表明:这种方法可以有效地改善氢气与空气的掺混效率,在计算的工况下使燃烧效率从60%提高到了64%;然而随着横喷空气的静压和马赫数的提高,会使燃烧室的总压恢复系数降低,并会使来流空气在台阶尖角处发生分离,接着会在台阶前的横截面产生激波,激波的位置也随着横喷空气的静压和马赫数的增加而前移。

Numerical Simulation on Supersonic Combustion over a Reward Facing Step with Transverse Hydrogen and Air Injection

In order to enhance the combustion efficiency of supersonic combustion chamber with a rearward facing step, this paper presents a new method which adds a transverse air injection after the hydrogen injection. A numerical simulation study of this method has been done using Reynolds stress model and finite-rate chemistry model with detailed chemical reaction mechanism of hydrogen-air combustion. The results show that this method may effectively enhance the mixing efficiency of hydrogen and air, and that the combustion efficiency is improved from 60% to 64% under the computational conditions. However, as the static pressure and Mach number of the transverse air injection increase, a separation of the supersonic air stream firstly arises at the corner of the step and then there will be a shock wave at the cross section of the step. After that the position of the shock wave gradually moves upstream. In addition, the total pressure loss increases.