废气涡轮增压器瞬态喘振机理及影响因素分析

Mechanism of Transient Surge and Influence Factor Analysis of Exhaust Turbochargers

废气涡轮增压器在低速阶段需要发动机的高转速和快速响应,这样可能会导致增压器在发动机转速急剧变化时产生瞬态喘振噪声。针对这一现象,结合增压器工作原理,阐述瞬态喘振机理,分析产生瞬态喘振的因素,建立基于发动机瞬态断油响应的GT-POWER发动机模型,并分析发动机进气歧管直径大小、长度、增压器转子转动惯量对瞬态喘振的影响,得出发动机进气歧管越长、直径越大、增压器转子转动惯量越小条件下,增压器喘振裕度越小的结论。通过优化增压器压气机进口结构,在增压器压气机进气口处增加流量拓宽槽,可有效解决发动机增压器的瞬态喘振噪声问题。

The exhaust turbocharges need high rotating speed and fast response of engines when operating in low speed condition.However,it may excite the turbulence in charged air and radiate transient surge noise when the engine throttle slackens sharply.In this paper,the mechanism of transient surge is explained and its influence factors are analyzed.The model of GT-POWER engine is established,and the influences of the engine’s intake manifold’s diameter,length,and turbo moment of inertia on the transient surge noise are analyzed.It is shown that the longer intake manifold,larger diameter and lower moment of turbo inertia can lead to more harmful consequence to the surge noise.On the other hand,optimizing the structure of the inlet system of the compressor,especially adding the extended airflow groove to the inlet can improve the transient surge noise obviously.