Numerical Simulation On Characteristic Of Phase Change Heat Storage Material

Energy shortage has become an very serious problem all over the world.Latent heat thermal energy storage (LHTES) can storage or release energy bychange the phase of material, which can be used to solve the nonconformityproblem on supply and demand time of thermal energy. Due to the merits ofhigh-density energy storage, easy to control and match, thermal Energyaccumulation is an very effective measurements to solve energy shortage andnonconformity problem, the research and application of LHTES technology hasattracted extensive attention all over the world. The process of phase changeaccompanied with heat conduction and convection, Which make the solution of theproblem of heat transfer with phase change complicated, in most case we have touse numerical simulation to solve this problem. In this paper, the software Fluentwas employed to simulate the impact factors and the ways to enhance heat transferin the process of phase change. The following topics are studied:(l)Physical and mathematical model of the shell and tube LHTES system wasset up under a constant temperature boundary condition. the solidification andmeltion process of LHTES was under different cliff side temperature when theshell-tube is horizontal and standing up. Natural convection in the meltion andsolidification process are calculated, and study the influence of natural convectionaction on phase change heat storage materials and heat release process. During theprocess of meltion, natural convection had a great influence on it, which greatlyaccelerated meltion rate in the melting process. During the solidification process,natural convection become very weak, and had less influence on it, which canprevent the solidification process.(2)With fin in the phase change heat storage device, we research heat transferenhancement in phase change heat storage system, a variety of different geometricsize of the rib structure of the phase change heat storage system was simulated. thenumber of fin, fin height and the fin thickness are how to influence phase changecompletion time was analyzed. in heat storage system, Results show that: theeffect of heat transfer in tube with fin is better than that in light tube, it can greatlyshorten the melting time and improves the transfer efficiency; geometry size of finhad a great influence on the efficiency of heat exchange system, increase thenumber, fin thickness and height of fin can effectively improve the heat transferrate and reduce the time of process to finish the phase change heat storage or heatrelease. When increasing fin height, heat transfer is better; but the trend of increase of the thickness and fin number improve the heat transfer effect will beslow down.