溅板式层板喷注单元燃烧特性数值分析

Numerical analysis on the combustion characteristics of splash platelet injector

为了获得喷注单元结构参数对喷注器燃烧特性的影响规律,利用数值分析方法对单喷嘴溅板式层板喷注单元气-气燃烧特性进行研究,考察燃烧室特征长度及出口层喷嘴宽度对气氧/甲烷流动及燃烧特性的影响。在求解气-气燃烧流场方面,采用带化学反应的湍流N-S方程进行描述,其中化学动力学反应模型采用简化的单步9组分模型。研究结果表明:燃烧室特征长度的增大有利于特征速度效率的增加;该条件下采用溅板式层板喷注单元所对应的燃烧室特征长度约为600 mm。对比分析发现,出口层喷嘴宽度取0.15 mm时,水组分摩尔分数与热力计算值差别最大;当其值取1.05 mm时,燃烧室头部区域截面温度上升最快,取0.45 mm时上升最慢。总的来说,出口层喷嘴宽度取0.75 mm时,燃烧长度最短,燃烧效率最大。

In order to obtain the influence law of structure parameters on the combustion characteristics,the numerical analysis of gaseous methane and gaseous oxygen GO2/GCH4 single-element splash platelet injector was investigated,and the characteristics of both chamber length and nozzle width of faceplate were studied. The chemical N-S equations were solved for the flow field,and 1-step 9-species chemical dynamic model was used to describe the reaction of methane and oxygen. The results indicate that,the characteristic velocity increases with the increase of characteristic chamber length. Under these design parameters,the corresponding value of chamber characteristic length is about 600 mm. By contrast,when the nozzle width is 0. 15 mm,the mole fraction of H2 O has the biggest difference from the theoretical value; the temperatures of flow field increase at the fastest level when the nozzle width equals to 1. 05 mm but increase at the slowest level when the nozzle width equals to 0. 45 mm. In short,the nozzle width equals to 0. 75 mm,the injector can reach the maximum combustion efficiency and the shortest combustion length compared to other cases.