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针对壁面均匀加热和非均匀加热情况下含非溶性表面活性剂液滴在预置液膜上的铺展过程,基于边界层流动理论建立了液膜厚度,表面活性剂浓度的非线性演化方程组。利用PDECOL程序对液膜厚度、表面活性剂浓度的演化历程进行了模拟计算,并分析了各参数对铺展特性的影响规律。结果表明,两种加热方式下液滴铺展结构不同,非均匀加热方式下铺展过程较为稳定;两种加热方式下,减少Marangoni数、气液界面的Biot数及增大液滴表面Peclet数均可使液滴铺展过程趋于缓慢;在非均匀加热方式下,选择适宜的加热强度也可以得到更为稳定的铺展过程。与含活性剂、初始厚度均匀的液膜受热流动相比,加热造成的Marangoni效应对液滴的影响更为显著。
In view of the spreading process of the droplets containing the insoluble surfactant on the prefilm liquid membrane under uniform heating and non-uniform heating of the wall, a nonlinear evolution equation of liquid film thickness and surfactant concentration was established based on the boundary layer flow theory. The PDECOL program was used to simulate the evolution of liquid film thickness and surfactant concentration, and the influence of various parameters on spreading properties was analyzed. The results show that the droplet spreading structure is different under the two heating methods and the spreading process is stable under the non-uniform heating method. Under the two heating methods, the Marangoni number, the Biot number of the gas-liquid interface and the Peclet number of the droplet surface can be decreased So that the droplet spreading process tends to be slow; in the non-uniform heating mode, select the appropriate heating intensity can also be more stable spreading process. Marangoni effect caused by heating has more significant effect on droplet than that of liquid film with active agent and initial thickness.