高原地区柴油机机油流动损失仿真与试验研究

针对某些柴油机在高原地区出现的机油压力偏低问题，通过试验测试、理论分析与计算流体力学仿真，对润滑系统各处的机油流动损失进行研究。研究结果表明：环境压力影响整个油路的基础压力，随着海拔的升高，压油泵前压力随环境压力等量降低，导致泵前机油汽化出现了吸空现象，使得机油质量流量下降，主油道压力明显降低；流量一定时，随着管径的增加管路流动损失逐渐降低，但流动损失变化率逐渐变小，直角弯头对流动损失影响很大，当弯管半径与管道半径大于1.5后，流动损失变化趋于平缓。试验表明：采用改进方案后，在低转速区域，发动机机油压力增加30%左右，中、高转速的机油压力提高50%以上。

Simulation and Experimental Research on Oil Flow Loss of Diesel Engine at Plateau

For low oil pressure in diesel engine at plateau, the lubrication system of the diesel engine is researched through experimental test, theoretical analysis and CFD simulation. The results show that the ambient pressure affects the basic pressure in the whole oil passage. The inlet pressure of the oil pump equivalently decreases with the increase in altitude, resulting in lower ambient pressure . In this condition, asuction appears in the pump, which may reduce the main oil pressure significantly. As the flow rate keeps constant, the pipe flow loss decreases gradually with the increase in pipe diameter.Though the flow loss rate becomes smaller,the right angle junction has great influence on the flow loss, and for r/R≥ 1.5, the change of flow loss tends to be stabile. The plateau test results show that the engine oil pressure of the improved scheme is increased by about 30% at low rotating speed, and the oil pressure is increased by more than 50% at medium and high rotating speeds.