一个新的高速直喷式柴油机的准维多区燃烧模型

A NEW QUASI-DIMENSIONAL MULTI-ZONE COMBUSTION MODEL FOR HIGH SPEED D. I. DIESEL ENGINES

一、前言 在直喷式柴油机燃烧模型中,由于准维模型比多维模型有较强的实用性,又比零维模型有较强的预测排放的能力,目前国内外都在积极地研究开发能反映较多信息的准维多区燃烧模型。由于在中小缸径柴油机中喷注碰壁现象是不可避免的,因此在燃烧模型中必须考虑喷注碰壁的影响。近年来虽然已经出现了一些考虑到喷注碰壁的燃烧模型。

This paperpresents a new quasi-dimensional multi-zone combustion model for high speed D. I. diesel engnes. The model is developed mainly on the basis of the experimental results obtained from an experimental study of the spray characteristics in a constant volume bomb by using the highspeed laser shadowgraphy and gaseous simulation. A new thermodynamics model and fourrelated sub-models : (1)spray mixing, (2)ignition delay, (3)heat release and (4)NOx emissin are developed. The impingement of fuel spray and its influence on the fuel/ air mixing proess and the development of boundary layer in the wall spray are considered in the spray mixig sub-model.By compaing the calculating results with the test data of a D. I. diesel engine with a bore of 130mm and stroke of 150mm, it is found that the calculating results agree quite well with the test resultsthroughout the operating range of the engine. The model is shown to be capable of predictig the engine performance and the NOx emission.