单个RP-3航空煤油液滴的超临界蒸发实验研究

Experimental Investigation on Supercritical Evaporation of

关键词:  RP-3航空煤油  超临界蒸发  蒸发常数  环境参数

Key words:  RP-3 aviation kerosene  Supercritical evaporation  Evaporation constant  Environmental parameters

摘要:

目前以航空发动机为背景的针对液态碳氢燃料的超临界蒸发研究很少，鉴于未来高性能航空发动机的研制需求，选取国产RP-3航空煤油为研究对象，对液滴的超临界蒸发进行了研究。分析了蒸发过程中不同环境参数下液滴无量纲直径的平方随时间的变化规律，实验结果表明超临界蒸发与常规亚临界蒸发特性存在很大的差异；根据实验结果绘制了液滴蒸发时间随环境参数变化的曲线图，并分析了蒸发过程中不稳定度的变化规律，发现在不同的温度范围内环境压力对液滴蒸发时间的影响规律是截然不同的，同时不稳定度Bi随环境温度及压力的升高而增大；对不同工况下液滴的瞬态蒸发常数以及平均蒸发常数进行了定量计算，分析认为影响液滴蒸发常数的两个主要因素是环境温度和环境压力，且后者占主导地位。

Abstract:

For current investigations related with aero-engines，there are few researches available on the supercritical evaporation of liquid hydrocarbon fuel. With the increasing requirements of high performance for aero-engines being considered，evaporation of the RP-3 aviation kerosene droplets under sub- and super-critical environment was experimentally investigated. Firstly，the variations of the square of non-dimensional diameters were explored in detail under different ambient temperature and pressure with time during the evaporation process. Comparisons of typical sub- and super-critical evaporation conditions were also made and analyzed with the purpose of studying distinction between two different evaporation conditions. Then，the curve of droplet evaporation lifetime varied with environmental parameters was plotted according to the experimental results. It is found that the influence of environmental pressure on droplet evaporation lifetime is completely distrinct in the various temperature ranges and the unsteadiness in the evaporation process gets greater with the increasing of ambient pressure and temperature simultaneously. Finally，quantitative calculation of droplet evaporation constant under different conditions were accomplished. The results show that ambient temperature and pressure are the two major factors which have a significant impact on droplet evaporation constant，and the ambient temperature plays an important role.