Study On High Temperature Chemical Heat Energy Storage Technology

With the rapid development of science and technology in recent years, mankind has already extended it's living and competition space to the outer space and sea bed. The fuel of every kind of space and undersurface equipments is restricted by their volume and weight. Traditional fuel can not fit with the requirement of modern technology already. The technology of carrying high density energy and releasing it when it is necessary is a technique difficult problem which is in urgent needed to be solved. Energy storage equipment is the key factor to solve the problem above which got more recognition of human being. Some developed countries have already devoted much more human and material resource to the research of the energy storage equipment and gained some results. Some domestic universities and research institutes did some research on the energy storage equipment too, they gained some considerable progress.This dissertation compared three kind of energy storage method under high temperature: graphite as the storage medium-apparent heat storage, 80.5% LiFs-19.5% CaF₂s mixture as storage medium-high temperature phase change heat storage and Li/SF₆ as storage medium-high temperature chemical heat storage. The characteristic of the high temperature chemical heat storage is the broad working temperature scope, adjustable temperature field in certain scope. Compared to traditional fuel, Li/SF₆ has higher energy density, the reaction resultant can be stored in the reactor in solid state, fuel and oxidant can be stored respectively, so it is convenient to be stored and shipped. It's disadvantage is the technique difficulty : because much heat released during reaction process, temperature is very high, the requirement of the reactor is so challenging, the price of the reaction fuel is higher too and there may be some danger.When there is not much data, numerical simulation method can be used to estimate the data which is difficult to gain through experiment method, save research expense, shorten the research period. Using numerical simulation method to analyze performance of high temperature chemical heat storage equipment and solve the engineering design difficulty is an important method to research the inner reaction mechanism of high temperature chemical heat storage equipment.This dissertation simulated the combustion reaction process on the liquid interface when sprayed SF₆ into the reactor which stored liquid state Li fuel. Set up math physical model of the 3-D laminar reaction current of high temperature chemical heat storage equipment. During the numerical simulation, applied the curvilinear coordinates for the complex geometry of the computational field; applied the first order upwind format to discretize equations; applied SIMPLE algorithm method to achieve pressure-velocity coupling and applied the multigrid scheme to obtain converged solution.Though the development of the current CFD and combustion theory is very well already, it can not simulate the temperature and pressure fields when gas-solid-liquid phases coexist. This dissertation simplified the chemical reaction model, neglected the effect of solid resultant and midst resultant. Used the laminar fmity-action-velocity model to simulate the combustion flow, including heat-change and mass-exchange etc. at the same time, in order to the insure feasibility and controllability of the project, an examination was done to validate the low-combustion process of Li/SF₆. With changing the mass of SF₆ the different states were measured and achieved the examinational aim.Through the experiment and numerical method, this word provided the data to optimize design and improve the performance of high temperature chemical heat storage equipments.