柴油机相继增压故障切换过程的瞬态仿真

建立了相继增压柴油机一维非定常流动的仿真程序,针对某船用相继增压柴油机空气阀和燃气阀异常开闭时的切换过程进行了多组模拟计算,并把计算与试验结果进行了对比,符合较好。结果表明:空气阀和燃气阀同时打开时将使受控涡轮增压器压气机进入喘振区;燃气阀打开而空气阀延迟6 s以上打开时容易使得基本涡轮增压器压气机进入喘振区;燃气阀打开而空气阀打不开时将导致停机,两阀之间的定时对切换过程有很大的影响。

Transient Simulation on the Faulty Switch Processes of Sequential Turbocharging System of Diesel Engine

A unsteady one-dimensional flow simulation code is designed for simulating the transient state performance of sequentially turbocharged diesel engines.The code is utilized to simulate the switch processes of the sequentially turbocharged diesel engine.A study is focused on the switch of the sequential turbocharging system during fault switch processes(gas and air valve opening timing).The result shows that the second turbocharger could work in surge zone when the gas valve and air valve are opened at the same time,and that the first turbocharger could work in surge zone when the interval of gas and air valve opening is 6s,and that the diesel engine may stall for an excessive interval of valve opening.The length of the delay has a great influence on the switch of the sequential turbocharging system.