不同锯齿对圆转矩形喷管红外辐射特征影响数值模拟

在考虑中心锥、波瓣混合器、火焰稳定器以及加力燃烧室筒体影响的条件下,将轴对称收扩喷管改型设计为圆转矩形基准喷管,进一步在喷管出口进行修型设计.并对不同锯齿喷管流动、换热与红外辐射特征进行了数值分析.得到如下结论:考虑高温部件后,喷管红外辐射强度的方向性特征更加明显;相比圆转矩形基准喷管,采用多个小尺寸锯齿时,射流高温区长度有一定缩短,采用单个大尺寸锯齿时,高温区长度进一步缩短,其正后方红外辐射强度降低;将轴对称收扩喷管改为圆转矩形喷管并加装锯齿后,强化尾喷流与外流掺混,降低其红外辐射强度的同时带来了一定的推力损失.

Numerical simulation on infrared radiation characteristics of round to rectangular nozzles with different chevrons considering engine components

Considering the impacts of the center cone, lobe mixer, flame holder and afteburner cavity, the round to rectangular nozzle transition from axial symmetry convergent-divergent nozzle was designed, different chevrons were devised and assembled to the nozzle exit. Numerical simulations were carried on the flow, heat transfer and infrared radiation characteristics. The results indicate that the precision of the infrared radiation intensity distributions were more in line with the actual rules by taking the hot components into account. Compared to the basic round to rectangular nozzle, the length of high-temperature regions decrease with multiple small chevrons and further decreasesd with simple large one, individually. Furthermore, the infrared radiation intensity decreases obviously detected from 0 degree. The plume mixing with ambient flow and infrared suppressing characteristics are enhanced in rectangular nozzle with chevrons from axis one. At the same time, it will cause a little thrust lost.