基于CFD方法分析优化天然气发动机进气均匀性

Analysis and Optimization of Intake Uniformity of Natural Gas Engine Based on Multi-Cylinder CFD Method

利用CONVERGE软件网格生成技术擅长处理气门、活塞这类运动边界问题的优势,搭建了包含完整进气管路、真实气缸以及排气管路在内的天然气发动机进气系统的多缸仿真模型,克服了常规建模方法无法计算各缸进气量的问题;相比三维的单缸模型,该多缸模型又能评估各缸流动的差异,拓展了计算能力。基于此方法分析了某国六天然气发动机的进气均匀性,并提出了优化均匀性的有效措施,结果表明,优化方案的进气均匀性得到显著提高。

Taking advantage of the grid generation technology which can deal with moving boundary problems such as valve and piston,a multi-cylinder simulation model of the natural gas engine intake system including a complete set of intake pipeline,real cylinders and exhaust pipelines was built based on CONVERGE software. It overcomes the problem that the conventional modeling method can’t calculate the intake quantity of each cylinder. Compared with the three-dimensional single cylinder model,this multi-cylinder model can also evaluate the difference of flow in each cylinder,which expands the calculation ability. Finally,the intake uniformity of a China six natural gas engine was analyzed by this method. An effective measure to optimize the intake uniformity was put forward. Results show that the intake uniformity of the optimized scheme was significantly improved.