Numerical Simulation Of The Technology Of Thermal Storage With Phase Change

Energy-saving and environmental protection is an important topic in the field of energy using. With the development of economy and elevation of people's living level, the over-exploitation of energy, the use in low efficiency, which have resulted in environment pollutions serious day by day, have became adverse factors of restricting economic development and social progress. The technology of thermal storage, which was able to solve the unbalance of energy supply and demand in time and space, has become an effective way in rational use of energy and reducing pollution. Thermal storage with phase change has become a new hot in energy using because of its advantages such as high energy storage density, charging with a constant temperature, easier to control and so on.The process of phase change accompanied with conduction and convection, which make the solution to the problem of heat transfer with phase change complicated, which in most case we have to turn to numerical simulation to solve. In this paper, the software Fluent was employed to simulate the impact factors and the ways to enhance heat transfer in the process of phase change. The process and conclusions are as follows:(1) Establish a phase change model under a constant temperature boundary condition, compare the simulated results with the experiment data, demonstrated the correctness of the compute model and compute method. Subsequently make an analysis on the situation nature convection influencing the heat storing and releasing process. The simulation result indicates that:â‘ During the melting process, because of the influence of natural convection, the top of phase change regional melts faster, temperature contour ramp to the top.â‘¡The higher the horizon, the more stable the temperature contour.â‘¢Natural convection in the melting and solidification process be of different functions, which accelerated melting rate in the melting process, and slowed down in solidification.(2)Add fins into the system of thermal storage with phase change, in order to increase the speed of heat storing. Firstly establish a simple cell model, compare the simulated results with the experiment data, which demonstrated the correctness of the simulate method. Then simulated cell models with different fins, and made an analysis on the thermal conductivity of fins, the mass flow of media, and the distance between two fins influencing on heat transfer coefficient. The insult indicates that:â‘ The fins, through which heat transfer to the phase change region in the axial direction, the greater thermal conductivity of the fin, the faster heat transfer;â‘¡Fins with different thermal conductivity play different roles in enhancement of heat transfer, graphite fins make heat transfer uniform in the region, and aluminum fin which accelerates heat storing, tend to have a local overheating;â‘¢The smaller the distance between two fins, the larger the heat transfer coefficient of the heat-transfer surface, which with little connection with the mass flow of thermal medial.