Inverse Analysis of Temperature Field Influenced by Seepage on Combustion Space Area in UCG

It is always difficult to accurately calculate the shape and size of CSA (combustion space area) in UCG (underground coal gasification) even by using existing measuring methods due to its deep burying. In the paper, we propose the shape model of CSA. Based on both high temperature of combustion CSA and the relatively constant temperature of underground, the influence mechanics of seepage on temperature field is analyzed, a control equation of temperature field influenced by seepage is established, and the solution of finite element is worked out. Aiming at the UCG in a certain area, this paper inverses the temperature field distribution with seepage effect by making use of in-situ detection data and finite element numerical software Comsol. During the process of inversion, the approximate volume of CSA is calculated by adjusting its section size to gain the temperature distribution of coal seam that most close to in-situ detection. This method is with certain practical significance.