| Generally, dissolved gases in condensation water can corrode the boiler, turbine, water heating system, pipeline, valve and so forth. Specifically, oxygen gas is the most corrosive one. Therefore, deoxidizing is a key link in the water treatment process. Removing the dissolved oxygen gas in the water as much as possible is necessary in order to extend the service life of the thermal equipment. For this purpose, some power plants remove oxygen in the condenser in order to reduce the equipment investment. Of which, bubbling deoxidizing has been used widely as a method of elaborate deoxidizing. However, heat and mass transfer mechanism of bubbling is still not clear, so the design of deaerator has no formulaic way of finding out.Based on the background, we use lattice Boltzmann method to study the variation of bubble motion.Lattice Boltzmann method (LBM) has been an emerging approach in the field of computational fluid dynamics (CFD) during the past few years. LBM is based on the theory of molecular dynamics and has a clear physical background. It has advantages such as naturally parallel computing, convenient handling of complex boundaries and simple programming. Hence, LBM has been preferably applied to resolve transport problems concerning porous media, multiphase flow and convection-diffusion. Further, many LBM simulations have been undertaken to investigate two-phase flow in the past two decades, and have been achieved fruitful results.In order to prove the feasibility of LBM in this study, simulations on the lid-driven flow and the Rayleigh-Benard natural convection were conducted firstly. After fully understanding the calculation process—Zheng model, an improved free energy model, was chosen by comparing three main multiphase flow models. The simulations of the Laplace law and the merger of two bubbles verified the accuracy of the model. Subsequently, a single bubble rising in viscous liquid under buoyancy was simulated, in which the influence of various parameters on the results was analyzed and the simulation results were compared with experimental results. Thereby, the movement of the saturated vapor bubbles in the subcooled water was studied with the thermal model. The performances of heat exchange of single bubble and double bubble were analyzed with the hope of providing useful information for the design of the deoxidizing equipment. In an isothermal environment the rising of the bubble driven by buoyancy was simulated. The results show that when the density ratio is larger than 10, it has little effect on the final shape and velocity of the bubble. But the viscosity ratio has a great effect on the final shape and velocity of the bubble. A smaller viscosity ratio induces larger deformation and smaller final velocity. Moreover, the performance is the most satisfying when the control domain size is four times of diameter. It is shown that the variation of the interface thickness, mobility coefficient and relaxation time has little effect on the simulation results. However, the values out of the reasonable range can decrease the computation stability and conservation. In the cases of high Reynolds number, the rise of the bubble is very unstable, and the mass loss is serious.In a non-isothermal environment the movement of the saturated vapor bubbles in the subcooled water was simulated. The results show that the bubble with an initial velocity can produce better heat transfer performance than the freely-rising bubble. But the heat transfer effect of the angled injection is not considerably different from that of the vertical injection. In cases of launching the bubbles vertically with interval time, bubbles should merge as rapidly as possible in order to achieve the best performance of heat exchange. The two bubbles which are injected horizontally also need to merge quickly. The initial launch distance is determined by Jacob number. The larger the absolute value of Jacob number is, the smaller the initial launch distance should be.
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