壁面温度对柴油喷雾碰壁质量分布的影响

Effect of Wall Temperature on Mass Distribution of Diesel Spray-Wall Impingement

基于AVLFIRE软件建立柴油喷雾及碰壁仿真计算模型,以定容燃烧弹中喷雾碰壁试验得出的数据为基础对模型进行标定与校核,然后对不同壁面温度条件下的喷雾碰壁特性进行仿真计算,得出了不同壁面温度时燃油的气相、液相和附壁油膜质量随时间的变化规律.结果表明:喷雾碰壁之前,液相质量随时间的增加而增加,碰壁之后,液相质量随时间的增加而减少;壁面温度对空间液相质量的分布及其随时间的变化规律影响不大;随着壁面温度升高,喷油结束之前气相质量随时间增加的速率稍有增加,而喷油结束之后气相质量随时间增加的速率明显增加,附壁油膜达到最大质量的变化速率降低,达到最大质量后,附壁油膜随时间减小的速率增加.

A diesel spray-wall impingement model was established by using AVL FIRE software. The model was calibrated and checked on the basis of experimental data obtained by a spray-wall impingement test in a constant volume combustion vessel. The spray-wall impingement characteristics were simulated for different wall temperatures. The mass distribution of vapor-and liquid-phase and the oil film attached on the wall as the time proceeds were studied for different wall temperatures. The results show that before the wall impingement,the mass of the liquid-phase increases as the time proceeds,while it decreases after the wall impingement. Wall temperature has little effect on the distribution of the liquid-phase and its change with the time. As the temperature of the wall surface increases,the rate of increase in the vapor-phase mass is improved slightly as the time proceeds before the end of injection,and it is improved significantly after the end of injection. The rate of increase in the mass of the oil film attached on the wall decreases before reaching the maximum mass,and the rate of decrease is improved after reaching the maximum mass.