Numeric Approachment Of Diffusion-convection-reaction Equations And Simulation Of Coal Spontaneous Combustion

This thesis is just one part of the project of " Numerical approaching method and simulation of the couple fields in coal spontaneous combustion" which is funded by NSF of Shaanxi province. By the role of mass or heat conversation, the control equation of thermal field and oxygen concentration model of coal spontaneous combustion in the XK-III detection oven were constructed, also were the boundary conditions introduced into. From the mathematical models, it can be seen that the two fields equations have seem form and coupled each other by the reaction item. So the simulation become the approachment of a coupled diffusion-convection-reaction equations. In this paper, two methods were used, alternative implicit prediction-verifyment finite difference and characteristic finite difference methods, to simulation the self-combustion process of Yima coal and Yanzhou coal. The result have a good coherency with the real experiment. Which proved that the model can be used for the prediction of coal spontaneous combustion process.The innovations of this paper are listed as following:1) Two finite difference methods were established for the coupled fields of diffusion-convection-reaction equations to simulate the coal spontaneous combustion. The result has higher accuracy compared with that resolved by others' single field models.2) Alternative implicit prediction-verifyment finite difference methods were constructed in this paper to solve the coupled diffusion-convection-reaction equations.3) Extend Qinxinqiang's characteristic difference method for one dimension equation into the resolvement of two dimension coupled diffusion-convection-reaction equations.