高温热表面油液蒸发的时变性热质传递模型与实验研究

Time-dependent heat and mass transfer model and experimental study on the hot surface evaporation process of liquid fuel

针对高温热表面油液蒸发热质传递过程的时变性,考虑这一过程中的对流传质传热,建立了热环境作用下油液蒸发的热质传递模型方程,通过无量纲变换,求得空间浓度分布和温度场随时间的变化规律。以庚烷为试验对象,对高温热表面油液蒸发过程进行了实验研究。理论分析与实验表明:庚烷蒸发过程中,刘易斯数大于1,传热速率大于传质速率;蒸发导致的质量损失与时间平方根的成正比,与液面的面积成正比,且与质量扩散系数的平方根成正比,饱和蒸气浓度越大,蒸发速率也越大。油液蒸发计算结果与试验结果基本一致,表明了模型的有效性。

Targeted on time-dependent characteristics of the heat and mass transfer process during the process hot Surface evaporation of liquid fuel, considering the convective heat and mass transfer of the process, a heat and mass transfer model of hot Surface evaporation of liquid fuel has been built. Through dimensionless transformation, ultimately the Time-dependent spatial concentration distribution and temperature field variation have been obtained. Set n-Heptanes as experimental object, an experi mental study on hot Surface evaporation of liquid fuel has been carried out. The theoretical analysis and experimental results have shown that in the evaporation process of n-Heptanes, Lewis number was greater than one; Heat transfer rate is greater than the mass transfer rate, the mass loss led by evaporation is directly proportional to the square root of time, the area of liq- uid surface, and the square root of Mass diffusion coefficient. The greater the volatility of liquid fuel is, the greater the evapo- ration rate was. The calculation results of the liquid fuel evaporation model are roughly consistent with the experimental re- suits, which show the validity of the model.