某汽油机分水套CFD分析研究

CFD Analysis and Research on a Gasoline Water Jacket Spacer

缸体水套的冷却液速度分布要求上大下小,这样有利于缸体温度分布均匀,降低热应力。可以通过在缸体水套中嵌入带导流结构的塑料分水套的方法帮助缸体水套冷却液速度分层。基于此方法原理,提出了去掉分水套改在缸体水套内壁面铸造相应导流肋片的两种方案,针对这两种方案与分水套用CFD分析手段进行了三种结构状态的流动和换热分析。主要分析了排气侧的换热系数分布、缸体水套上下部速度分层效果以及垫片水孔水流量分配变化,从而提出采用分水套冷却的必然性。

Ideal velocity distribution on block water jacket wall is up high and down low, which is helpful to uniform temperature distribution of block and reducing thermal stress. An effective way of helping block water jacket velocity delamination is to embed a plastic spacer in it. Based on this method and principle, two projects are brought out, which add guiding ribworks on block wall and cancel the spacer. Aiming at these two projects and the spacer, flow and heat transfer of the three constructions are analyzed by CFD analysis means, mainly the exhaust side heat transfer coefficient distribution, block jacket velocity delamination and gasket holes＇ water flux distribution of a 2.4L gasoline water jacket with spacer and two improved constructions. The analysis results validate the necessity of spacer.