伪势格子Boltzmann方法的汽化热阱效应模拟研究

Simulation of the Heat Trap Effect of Vaporization Using the Pseudo-Potential Lattice Boltzmann Method

采用伪势格子Boltzmann方法的气液相变模型对饱和状态下亲疏水壁面上单气泡的相变传热进行直接的数值模拟.从结果中观察到:加热初期,亲水壁面与发生相变的气液界面之间存在液体微层;疏水壁面的相变则紧贴壁面进行,即疏水壁面近壁处不存在气液界面.模拟亲水壁面在不同时刻热源与气液界面之间的温差变化曲线,以及不同时间段近壁处的热流密度变化曲线,模拟结果表明气液界面的存在对传热起到强化作用.模拟同一温度下不同重力加速度与气泡脱离直径大小的关系曲线,其结果符合Fritz理论,从而对伪势格子Boltzmann方法的气液相变模型进行定性验证.

The phase change heat transfer of a single bubble on a hydrophilic and hydrophobic wall in saturated state is simulated numerically using the pseudo-potential lattice Boltzmann method.From the results,it is observed that there is a liquid microlayer between the hydrophilic wall and the gas-liquid interface at the initial stage of heating,while the phase transition of the hydrophobic wall is close to the wall,that is,there is no gas-liquid interface near the hydrophobic wall.The temperature difference curves between the heat source and the gas-liquid interface on the hydrophilic wall at different times and the heat flux curves near the wall at different times are simulated.The simulation results show that the existence of the gas-liquid interface can strengthen the heat transfer.At the same time,the relationship between different gravity accelerations and bubble detachment diameters at the same temperature are simulated,and the results are consistent with Fritz theory.Thus,the pseudo-potential lattice Boltzmann method of gas-liquid phase model is qualitatively verified.