凹腔/支板结构亚燃冲压燃烧室性能

Performance of ramjet combustor based on cavity/strut structure

为了避免基于凹腔火焰稳定器的亚燃冲压燃烧室壁面喷注时燃料与主流空气掺混非均匀性问题和提高燃烧室的性能,提出在亚燃冲压燃烧室中使用支板喷注代替壁面喷注的方案,数值模拟了凹腔/支板结构亚燃冲压燃烧室中燃料分布及流场结构,并分析了支板结构对燃料空气混合及燃烧室性能的影响。研究表明:支板虽然使燃烧室出口的总压恢复系数相对于壁面喷注方式下的降低了6.3%,但能使燃料均匀分布于整个流道内,增强了燃料与空气掺混,使燃烧室出口的混合效率和燃烧效率分别提高了21.4%和20.5%。燃烧效率的提高弥补了采用支板导致的燃烧室内气流的额外总压损失所带来的机械能损失,使得支板喷注时燃烧室出口的比冲提高了39.6%。因此,在亚燃冲压燃烧室中设置凹腔/支板结构,有利于提高燃烧室整体性能。

Strut injection was proposed to replace wall injection in ramjet combustaor,in order to promote the combustion efficiency and avoid the problem of inhomogeneous mixing of fuel and mainstream,which was caused by fuel centralized near the wall with wall injection in ramjet combustor based on cavity flameholder.The distribution of fuel and flow field structure in ramjet combustor based on cavity/strut structure was simulated.The effects of strut on mixing and performance of ramjet combustor were studied.It was found that the strut made homogeneous fuel distribution in the whole flow channel,enhanced the mixing of fuel and air,enhanced the mixing efficiency and combustion efficiency of the combustor exit by 21.4% and 20.5% respectively,although it reduced the total pressure recovery coefficient of the combustor exit by 6.3% compared with that under the wall injection method.The improvement of combustion efficiency made up the additional total pressure loss,and increased the specific impulse of the combustor exit by 39.6% under the strut injection method.Therefore,it is good for improving the combustor performance when the cavity/strut structure is used in ramjet combustor.