主燃级喷点数目对回流燃烧室的影响研究

Effects of Number of Main Fuel Injection Points on Reversed-Flow Combustor

关键词:  回流燃烧室  主燃级  多点喷射  NO_x排放  数值分析

Key words:  Reversed-flow combustor  Main stage  Multi-point injection  NO_x emission  Numerical simulation

摘要:

为了研究主燃级周向燃油喷点数目对回流燃烧室NO_x排放的影响，采用数值模拟方法对一种带有主燃级多点燃油直接喷射、贫油预混预蒸发头部的回流燃烧室流场进行研究，分析了回流燃烧室的冷态及热态流场特征和主燃级周向燃油喷点数目对NO_x排放特性的影响。结果表明：（1）主燃级喷点数目对速度场的影响主要集中在主燃级出口下游，对预燃级出口速度场影响较小。（2）随周向喷点数目增加，油气掺混效果改善，高温区收缩，NO_x排放量降低。（3）NO_x质量分数分布受速度场和温度场耦合影响，主要集中于预燃级下游的高温低速回流区内。

Abstract:

In order to study the effects of number of main fuel injection points on NO_x emission in reversed-flow combustor， numerical simulation was used to research the flow fields in the reversed-flow combustor with main fuel multi-point direct injection and lean premixed prevaporized injector. The characteristics of cold and hot flow fields in reversed-flow combustor were analyzed. The effects of number of main fuel injection points on NO_x emission were analyzed. The results show that the number of main fuel injection points mainly affects the downstream velocity field of main stage， but has little effect on the downstream velocity field of pilot stage. As the number of circumferential injection points increases， the fuel-air mixing effect is improved， the high temperature zone shrinks and NO_x emissions decrease. NO_x mass fraction distribution is affected by the coupling of velocity and temperature fields. NO_x is mainly distributed in the high temperature and low speed recirculation zone downstream of the pilot stage.