2D Numerical Simulation Of Geothermal Field With Finite Element Method

:The heat energy contained in the interior of Earth is very huge, the effect of heat conduction and convection lead to the formation and evolution of the geological structure in the Earth’s interior. Understanding the distribution of geothermal field in the Earth’s interior is important for the geothermal theoretical research, the same time it has important guiding value for the development and utilization of geothermal energy and the exploration of oil and gas. Therefore, the numerical simulation of the geothermal field and the study of the distribution of the geothermal field are necessary and important.In this paper, the finite element method is applied for the solution of the heat transfer equation in the terrestrial heat field, and the FORTRAN computer language is used for the preparation of the corresponding two-dimensional numerical simulation in the geothermal field. Numerical simulation in the geothermal field is divided into the following steps:automatic meshing in the entire calculated area, the delineation of abnormal medium areas and convection zone, the determination of boundary conditions, the calculation of the geothermal field and then drawing the contour map of temperature.Due to the differences of thermal physical parameters in the various kinds of rocks, the movement of geothermal fluid such as groundwater, the intrusion of high-temperature magma body, the undulation of terrain, and so on in the Earth’s crust, the distribution of terrestrial heat field is effected in different degrees. Therefore, references to the relevant literature, five kinds of geothermal models are designed in this paper, and these models are calculated with finite element method. Then according to the calculated values of temperature, the corresponding contours are drawn with Surfer software. Comparing and analyzing the simulated results, and then summarizing the influence laws of anomalies, abnormal areas and convection zones in the entire calculated areas of the geothermal field.The intrusion of high-temperature magma body has the lager impact on the geothermal field around it in the early stage. With times going, the impact of magma body decreases, and finally reaches equilibrium with the surrounding temperature field. In this process, the rate of the change of surrounding rock’ temperature is related to the distance between the magma body and the surrounding rock. The distance is closer, the rate of the increase or decrease of the temperature is faster, and the slower anyway. Different types of rocks have different thermal physical parameters, and the distribution of geothermal field is not the same. In different rock formations, the thermal conductivity is larger, the contour of temperature is sparser, and the thermal conductivity is smaller, the contour of temperature is more intensive. The convection of the fluid has a great impact on the surrounding temperature field. When the area is nearer to the convection zones, the influence is more significant, and farther away from the convection zones, the influence is smaller. Along the flow direction of the fluid, a certain degree of curvature are projected on the curves of temperature forward, as the change of time, the range of the temperature field affected gradually increase.