石脑油及原油边界层蒸发特性的实验研究

从环境风速、蒸发面积和蒸发液池与地面相对位置3方面分别对石脑油和原油的蒸发动力学特性进行了风洞实验研究。实验结果表明,石脑油在低风速和液面面积较小的情况下,石脑油的蒸发受风速和液面面积的影响明显,增加风速或增大液面面积后,影响减弱。这表明石脑油的蒸发在一定程度上受边界层蒸发控制。原油的蒸发几乎不受风速、液池面积的影响,这说明原油的蒸发受边界层条件控制的程度很小,其蒸发速率主要由其自身性质(如分子扩散系数、蒸气压等)所决定,其蒸发过程是受基本蒸发过程控制的。通过对实验数据进行分析,石脑油的蒸发质量随时间表现出乘幂的变化关系,幂次大约为0.70;原油的蒸发质量随时间表现出乘幂或对数的变化关系,其幂次大约为0.55。

Experimental Research on Evaporation Characteristic of Naphtha and Crude Oil in Boundary Layer

The dynamic characteristics of evaporation process for naphtha and crude oil were researched in three aspects of different wind speed,evaporation area and relative location of evaporation surface to ground in wind tunnel.The results indicate that the evaporation of naphtha is notably influenced by wind speed and evaporation area when the wind speed is low and evaporation area is small, influence becomes weak with the increase of wind speed and evaporation area,which shows the evaporation process for naphtha is controlled by boundary layer evaporation at some degree.The evaporation of crude oil is almost not influenced by wind speed and evaporation area,which shows the evaporation process for crude oil is not controlled by boundary layer evaporation,its evaporation rate is controlled by the nature itself and evaporation process is controlled by basic evaporation process.On the basis of analysis for experimental data,the relationship of power between evaporation mass and time for naphtha was found and the average value of the power is about 0.70.The relationship of power or logarithm between them for crude oil was found and the average value of the power is about 0.55.