直喷式柴油机性能与排放的准维模拟

建立了直喷式柴油机缸内燃空混合与燃烧过程的多区准维模型，考虑了滴径分布、液滴蒸发、着火延迟、对流与辐射换热、缸内温度均匀化和空气涡流的瞬时角速度等影响性能和排放的主要因素，并采用紊流射流理论推出了一个壁面射流模型，在正确描述喷注贯穿的基础上细致地建立了空气卷吸模型。建立了ＮＯx模型和反映碳烟成核、增长和表面凝聚的微观机理模型，初步分析了燃烧室形状对涡流衰减和排放的影响。通过对１０个工况的计算表明，模型预测与实测结果基本吻合，具有一定的实用性。

Quasi-Dimension Modeling of Performance and Emissions for Direct Injection Diesel Engines

A model for the prediction of air-fuel mixing and combustion process of DI diesel engines has been formulated and developed.This model is a quasi-dimensional one and is based on multi-zone spray-mixing approach.The model considers the main factors affecting performance and emissions such as the drop size distribution,vaporation,ignition delay,convective and radiative heat transfer,temperature homogenization in the cylinder and instantaneous swirl,etc.The theory of turbulent jet has been employed to induce a model of wall jet.On the basis of spray penetration,air entrainment model has been built in a meticulous way.Furthermore,a model for prediction of NO x and a model that shows soot nuclei,spherule growth and aggregation have been developed.The effect of piston bowl shape on swirl and emissions has been analyzed.Through calculations for 10 working conditions,good agreement between theoretical and experimental results shows the validity of the model.