蒸发管蒸发效率的试验与管内两相流动的数值模拟

为研究微型燃烧室蒸发管的雾化蒸发性能，试验研究了进气温度、气油比（AFR）、管壁温度和进口空气流速对燃油蒸发率的影响。试验结果表明:进气温度和进口空气流速是影响蒸发效率的两个主要因素；当气油比减小到3.0时，管内两相流型由膜态沸腾向过渡态沸腾转变，该状态下燃油与管壁的换热效率最低。蒸发管数值仿真引入离散相模型（DPM）和液滴碰壁飞溅模型，蒸发效率计算结果与试验数据呈现相同趋势。在此基础上研究了气动参数对燃油雾化的影响。计算结果表明，进口空气流速的提高可以改善燃油雾化细度，但不利于液滴分布的均匀性，索太尔平均直径（SMD）与进口空气流速的-1.69次方成正比。 

Experiment on evaporation efficiency of vaporizer andnumerical simulation of two-phase flow in vaporizer

To study the atomization and evaporation charactertistics of rear intake vaporizer, the experiment researched the influences of intake temperature, air fuel ratio (AFR), wall temperature and inlet air velocity on evaporation efficiency. Result of the experiment showed that intake temperature and inlet air velocity were two major factors influencing evaporation efficiency; when AFR decreased to 3.0, the flow pattern transformed from film boiling to transition boiling, now heat efficiency was the lowest. Discrete phase model (DPM) and droplet splashing model were employed to simulate the two-phase flow in the vaporizer. Calculation of evaporation efficiency was in reasonable agreement with experimental data. The numerical results show that the increase of inlet air velocity can improve the atomization quality, but it is not conducive to the uniformity of droplet distribution. Sauter mean diameters（SMD） is proportional to the -1.69 power of inlet air velocity.