N_2O/C_3H_8火炬式点火器工作性能数值模拟研究

Numerical simulation for operation performance of N_2O/C_3H_8 torch igniter

采用数值计算方法对氧化亚氮/丙烷火炬式点火器的燃烧室和火炬流场特性进行了数值仿真研究,获得了点火器在定混合比工况下工质流量对火炬性能的影响以及定流量工况下余氧系数对火炬性能的影响:在定余氧系数0.350工况下点火器燃烧室压强、火炬功率和点火有效长度与点火器的流量基本呈线性关系,有效火炬长度与实验中所观察到的基本一致;在定流量9 g/s工况下点火器燃烧室压强、喷管出口温度、火炬功率和点火有效长度随余氧系数的不断增加均先迅速增加到最高值后开始逐渐减小,燃烧室压强、喷管出口温度、火炬功率和点火有效长度的计算最高值分别为1.73 MPa,2 823 K,33.14 kW和86.5 mm。

The combustor and torch flow field characteristics of N20/C3Hs torch igniter were simulated numerically, from which the influences of mass flow rate of the igniter and excess-oxidizer coefficient on ignition performance were derived. The results can be summarized as follows： the combustor pressure, torch power add effective torch ignition length has a linear relationship with mass flow rate under the condition of excess-oxidizer coefficient 0.350, the simulation results of effective torch length are basically identical With the results observed in igniter experiment, and the Mach disk in the velocity flow field of the torch is increased obviously with the increase of mass flow rate. The combustor pressure, nozzle outlet temperature, torch power and effective torch ignition length are increased rapidly to the maximum values of 1.73 MPa, 2 823 K, 33.14 kW and 86.5 mm at first, and then decreased gradually with the increase of excess-oxidizer coefficient at the mass flow rate 9 g/s.