车用发动机模拟排气脉冲发生器的设计及涡轮非稳态特性

摘要

A pulse generator rotating disc profile optimization and a pulse generator calculation method were put forward based on engine exhaust characteristic and goal of generator design. Calculation results show that the improved pressure wave of generator is more close to the practical one. Experimental pressure wave agrees well with calculated pressure wave and target wave, and this confirms the feasibility and validation of optimization and calculation method. Dynamic characteristics of turbine corresponding to rated conditions of ICE were studied. Result shows large deviation form steady characteristics, and this indicates that the "quasi-steady" hypothesis is inadequate in handling the pulse flow case.%在分析发动机排气压力波特征、明确脉冲发生器设计目标的基础上,提出了脉冲发生器转动盘开口型线的改进方案和脉冲发生器的设计计算方法.结果表明,改进后的压力波更加贴近于实际的压力波.利用试验对改进方案进行了验证,由试验得到的压力波与计算结果和目标值吻合较好,证明了设计计算方法的可行性和改型方案的正确性.搭建了涡轮非稳态特性试验台,对涡轮工作在发动机标定工况下的特性进行了试验研究,发现涡轮的非稳态特性与稳态特性存在着比较大的偏离,例证了“准稳态”假设在处理非稳态问题时存在着很大的不足.