温度及压力对柴油机燃烧室内混合气形成影响的数值模拟

用CFD分析软件对柴油机燃烧室内不同环境条件下柴油喷雾的混合气形成及撞壁混合过程进行了模拟计算，并与PLIF法取得的试验结果进行了对比，二者基本吻合．试验和模拟计算结果均表明，油束撞壁后主要沿燃烧室壁面向下移动，在燃烧室近壁区形成一层薄而浓、面积较大的混合气层，且随燃烧室内气体密度的增大，对应时刻及位置的速度、喷雾贯穿距、燃烧室壁面的燃油堆积量、近壁区浓混合气层的面积及混合气浓度减小．

Numerical Simulation of the Effects of Temperatures and Pressures on Mixture Formation in the Combustion Chamber of a Diesel Engine

Numerical simulation of the mixture formation and wall-impingement mixing process of a diesel spray under different environmental conditions in the combustion chamber of a diesel engine was carried out by means of a CFD three-dimensional numerical analysis software. The computed results were in good agreement with the experimental ones obtained by planar laser-induced fluorescence (PLIF) method by comparison. Both measured and computed results indicated that the wall-impingement spray would crawl downward the wall surface of the combustion chamber and form a thin and rich layer of mixture with an extensive area after it impinged on the wall. And with the gas density in the combustion chamber increasing, the corresponding timing and location velocity, spray tip penetration, the amount of fuel accumulating on the wall, the area of the rich mixture layer near the wall and the concentration of the mixture in the combustion chamber decreased.