Abstract: In view of the bad extraction effect for discontinuous space position of extraction point, serious waste of pipe and high extraction cost in the traditional buried tube gas extraction technology in upper corner of working face, the gas tube extraction technology in the upper corner was introduced in this paper, which can make the extraction point matching the face advancing speed, realize the continuity of the best goaf gas extraction effect, recover pipes and materials, and reduce the extraction cost. The selection of optimal location of goaf gas extraction, namely the determination of extraction parameters, is the successful implementation of gas tube extraction of the upper corner. The behavior of gas diffusion and flow were described by using Brinkman equation, Fick diffusion law and gas diffusion translation equation, and the multi-physical field coupling model of gas flow in working face was established. Then, the optimal layout parameters of the tube extraction were determined by Fluent calculation of the model, and was applied to the practice and effect test. The results show that the numerical simulations are basically in accordance with the field test results, and the optimum extraction position has been determined as 2.4 m from the floor, 1.57 m from the air-return roadway along the inclined direction, and 17.4 m deep into the goaf along the strike. Gas overrun in the upper corner has been eliminated during the application, which proves that the gas tube extraction technology in the upper corner has a good applicability and feasibility.

Key words: upper corner, tube extraction technology, coupling model, Fluent