基于GT-Power对HCNG发动机的数值模拟

Numerical simulation of HCNG engine on GT-Power

为了对HCNG发动机进行更系统理论的研究,运用模拟软件GT-Power建立YC6J天然气掺氢发动机的仿真模型.仿真数据与原机外特性试验结果对比的误差在5%以内,证明该模型具有较高的准确性.然后通过该仿真模型,进行过量空气系数和点火提前角与燃用不同掺氢比例的HCNG关系的模拟研究.研究结果表明,HCNG掺氢比越大,所对应的最佳点火提前角越小,同时着火极限越宽;在较小的点火提前角或者较大的过量空气系数时,掺氢HCNG能有效地提高热效率,降低燃料消耗;HCNG发动机的NOx排放相比CNG虽有所增加,但可通过减少点火提前角或增大过量空气系数降低NOx排放.同时针对模拟工况,确定最佳的点火提前角和过量空气系数,为HCNG发动机的开发标定,起到理论指导作用.

In order to have a better systematic theoretical research about HCNG engine, a simulation model of YC6J HCNG engine was built by GT-Power. The simulation deviation was less than 5 % by comparing with the experimental results at full load condition which confirmed the accuracy of the model. Then the research of the engine using different hydrogen-CNG ratios was conducted when the excess air ratio and the spark advance angle were different. The results show that the optimal spark advance angle decreases and ignition limit becomes wide with the increase of hydrogen mixing ratio. HCNG can increase the thermal efficiency and decrease fuel consumption effectively when the spark advance angle is small or the excess air ratio is large. The NOt emissions are reduced greatly by increasing the excess air ratio or decreasing the spark advance angle although the NOx emissions of HCNG are more than CNG. At the same time, as to the simulated condition, the optimal spark advance angle and excess air ratio were determined which had a theoretical guide to the development of HCNG engine.