高湿氢氧喷注器数值分析与正交设计

Numerical simulation and orthogonal optimization design for high humidity hydrogen oxygen injector

采用基于数值模拟的正交实验优化设计方法对应用于氢氧蒸汽发生器的高湿氢氧同轴剪切喷注器进行研究,分析燃烧室流场、温度场和组分分布情况.以燃烧长度作为燃烧性能评价指标,以燃烧室壁面平均温度作为壁面热负荷的评价指标,研究氧气喷注速度（20~40m/s）、高湿氢氧速度比（3~7）和氧喷嘴端面厚度（0.5~1.5mm）对高湿氢氧燃烧器燃烧性能和燃烧室壁面热负荷的影响.结果表明：燃烧室头部存在利于点火和维持稳定燃烧的回流区,高湿氢气和氧气射流之间存在高温剪切燃烧层.高湿氢氧速度比对燃烧性能和燃烧室壁面热负荷的影响最为显著,氧喷注速度次之;而氧喷嘴端面厚度影响对燃烧性能和燃烧室壁面热负荷的影响均不明显.增大氧气喷注速度和速度比会缩短燃烧长度,提高燃烧性能,但同时增大燃烧室壁面热负荷.高湿氢氧速度比和氧气喷注速度的交互作用对燃烧性能、燃烧室壁面热负荷的影响显著,其他参数交互作用产生的影响都非常小.在所研究的工况范围内,最短燃烧室长度为68mm,最低壁面温度燃气温度为1 966.9K.

The performance of a high humidity hydrogen/oxygen shear coaxial injector applied in oxy- hydrogen steam generator was studied through a CFD-based orthogonal experiment design method. The flow field, temperature field and composition distribution were analyzed. The influences of oxygen velocity （20-40 m/s）, the velocity ratio of high humidity hydrogen to oxygen （3-7） and the oxygen post tip wall thickness （0. 5-1. 5 mm） on combustion performance and the heat load of combustion chamber were explored. Results show that the recirculation zone near the combustor dome can promote ignition and combustion stability, and there is flame in the shear layer between the high humidity hydrogen jet and the oxygen jet. The velocity ratio of high humidity hydrogen to oxygen has most remarkable influence on the combustion performance and the heat load of combustion chamber, and the oxygen velocity is the second major factor, while the oxygen post tip wall thickness has insignificant influence. The increase of oxygen velocity or velocity ratio will shorten the length of combustion length, improving the combustion performance, but will increase the chamber heat load. The interaction between velocity ratio and oxygen velocity has remarkable influence on the combustion performance and the heat load of combustion chamber, while the interaction of other parameters has insignificant influence. As a result, the shortest combustion length is 68 mm and the lowest wall temperature is 1 966.9 K.