旁侧进气凹腔燃烧室三维流场对比分析研究

Comparative Analysis of Three Dimensional Flow Field Side-dump Combustor Cavity Combustor

针对冲压发动机双下侧90°进气的旁侧进气突扩燃烧室,加入凹腔(360°圆周)形成组合火焰稳定器,得到旁侧进气突扩凹腔燃烧室方案Ⅰ;基于方案Ⅰ将360°圆周改为270°圆周的凹腔,得到方案Ⅱ。采用三维两相数值计算方法,针对两种燃烧室方案进行了设计点Ma 4.5,海拔高度26 km条件下的仿真计算,给出了燃烧室性能参数,同时对燃烧室的马赫数、静温、静压和涡结构分布等进行了对比分析。结果表明:凹腔火焰稳定器能够促进气流周向运动,提高燃料驻留时间,有利于气流与燃料掺混;凹腔对燃烧室入口上游流场影响较小,对凹腔段及燃烧室下游流场影响较大;燃烧趋向中心燃烧,近壁面沿径向存在温度梯度,合理利用有利于热防护。

Aiming at the side inlet sudden expansion combustor of ramjet with double lower 90°inlet,a cavity(360°circumference)is added to form a combined flame holder to obtain the side inlet sudden expansion combustor(scheme 1);based on Scheme 1,a cavity with 360°circumference is changed into 270°circumference to obtain scheme 2.Based on the three-dimensional two-phase numerical calculation method,the simulation calculation was carried out under the condition of design point Ma4.5 and altitude 26 km,and the performance parameters of the combustor were given.At the same time,the Mach number,static temperature,static pressure and vortex structure distribution of the combustor were compared and analyzed.The results show that:the cavity flame holder can promote the circumferential movement of gas flow,improve the residence time of fuel,which is conducive to the mixing of gas flow and fuel;the cavity has little influence on the flow field upstream of the combustor inlet,but has great influence on the flow field downstream of the combustor and the cavity section;the combustion tends to center combustion,and there is a temperature gradient along the radial direction near the wall,so reasonable utilization is conducive to thermal protection.