两次喷射策略下的预主喷射喷雾与燃烧特性研究

Study on Spray and Combustion Characteristics of Pilot-Main Injection Under Two-Injection Strategy

基于定容燃烧弹系统,分别采用米氏散射法、自发火焰发光法、OH化学荧光法研究了两次喷射策略下喷雾和燃烧特性及预喷射对主喷射的影响。研究分析发现:相比单次喷射,两次喷射在预喷射作用下,主喷射着火位置更加靠近喷嘴且着火延迟期与火焰浮起长度变短;随着预喷射与主喷射时间间隔增加,主喷射喷雾锥角减小,着火延迟期增加,但着火位置无明显差异;间隔时间为0.9ms时火焰最暗,间隔时间为1.2ms时火焰最亮。

Based on a constant volume combustion chamber,the effects of pilot and main injections of two-injection strategy as well as the dwell time between them on spray and combustion were studied.The spray was studied by using Mie-scattering imaging technique,and the combustion was investigated with the flame luminosity imaging and OH chemiluminescence techniques.The result shows that,compared with one-injection strategy,the ignition location of the main injection of two-injection strategy is closer to injector,and the ignition delay time and flame lift-off length are shorter.When using two-injection strategy,the spray cone angle of the main injection decreases and the ignition delay time increases with the increase of the dwell time.Besides,the dwell time has no obvious influence on the ignition location and flame lift-off length.The flame luminosity is the weakest when the dwell time is 0.9 ms and the strongest when the dwell time is 1.2 ms.