燃烧室结构对天然气转子发动机燃烧过程的影响

以一台由端面进气汽油转子发动机改装而来的预混天然气转子发动机为研究对象，在FLUENT软件的基础上通过编程实现转子发动机三维网格的偏心运动，并选择合适的湍流模型、燃烧模型以及详细的CHEMKIN化学反应机理，建立基于化学反应动力学的端面进气天然气转子发动机三维动态数值模拟模型。通过与试验数据进行对比和分析，验证模型的可靠性。在此基础上，研究燃烧室结构对端面进气天然气转子发动机的缸内流场、温度场和中间产物浓度场的影响。结果表明，当燃烧室凹坑布置于转子曲面长度方向的前端和转子曲面宽度方向的中心时，燃烧过程同时利用了燃烧室后部的滚流以及燃烧室中部高速流区对火焰的加速作用，缸内整体燃烧速率最大。同时，其缸内压力最大以及中间产物OH的生成量也最大，其压力峰值比中置凹坑燃烧室提高了19.9%，但其NO质量分数仍在0.5%以内。

Influence of Combustion Chamber Configuration on Combustion Process of Natural Gas-fueled Rotary Engines

Taking a side ported pre-mixed natural gas-fueled rotary engine converted from a gasoline rotary engine as the study object. On the basis of the Fluent simulation software, a three-dimensional dynamic simulation model is established by writing dynamic mesh programs and choosing the reasonable turbulent model, combustion model, CHEMKIN mechanism. The three-dimensional dynamic simulation model based on the chemical reaction kinetics is also validated by the experimental data. On this basis, the three-dimensional dynamic characteristics for flow, temperature field and the combustion intermediate product under different combustion chamber configuration are analyzed. The results show that when the rotor pocket is located at the front end of rotor surface along length direction and the center of the rotor surface along width direction, a tumble in the rear of combustion chamber and a high speed flow in the middle of combustion chamber are made full use to increase flame speed. The flame propagation speed reaches the maximum value. The indicator diagram is best and the production of OH is biggest. Comparing with mid pocket combustion chamber, the front pocket combustion chamber shows a 19.9 percent increase in the peak pressures, but NO emission mass fraction still stay within 0.5 percent.