二维水平通道内流动沸腾换热的格子Boltzmann模拟

利用格子Boltzmann方法模拟二维水平通道内水的流动沸腾过程，获得不同壁面过热度下流型特点和不同因素对换热过程的影响规律。结果表明，随着壁面过热度升高，流道内流型依次经历从泡状流、弹状流到反环流的转变，平均热流密度和平均换热系数先增大后减小。入口流速降低会使流道内出现受限气泡流，核态沸腾受到抑制。提高入口流速能够有效促进气泡脱离，壁面平均换热系数随入口流速增大而增大，但增长速率有所减小。减小通道宽度有利于汽化现象发生，核态沸腾得到强化，壁面平均换热系数有所提高。

Lattice Boltzmann simulation of flow boiling heat transfer in two-dimensional horizontal channels

In this paper,the flow boiling of water in a two-dimensional horizontal channel was simulated by the lattice Boltzmann method.The characteristics of flow patterns under different wall superheat and the influence laws of different factors on the heat transfer were obtained.The results show that with the increase of wall superheat,the flow pattern in the channel undergoes a transition from bubble flow,slug flow to invert-annuler flow.The average heat flux and the average heat transfer coefficient increase first and then decrease.The decrease of the inlet velocity leads to the restricted bubble flow in the flow channel and inhibits the nuclear boiling,while the increase of the inlet velocity can effectively promote the departure of the bubbles.The average heat transfer coefficient of the wall increases with the increase of the inlet velocity,but the growth rate decreases.Reducing the channel width is conducive to the occurrence of vaporization,enhancement of the nucleate boiling and increase of the average heat transfer coefficient of the wall.