Simulation And Optimum Design Of Flow Distribution At Inlet And Outlet Diversion System For Thermal Flow-reversal Reactor

Coal mine methane is a kind of high quality, efficient and clean gas energy, a large number of it is discharged into the atmosphere by coal mine ventilation air system directly because it is difficult to mine and utilize, which is a great damage to the environment and a wasted energy resource. In order to mitigate the coal mine ventilation air methane effectively, thermal flow-reversal reactor (TFRR) technology is developed, and is proved to be a promising technology for lean methane oxidation.In this paper, a combination method of model experiment and numerical calculation was used to investigate the flow uniformity in the TFRR, by taking the thermal flow reversal reactor studied by Shandong University of Technology as antitype. The study about flow distribution includes three parts:1) The cold test device was designed and built on the basis of the TFRR studied by Shandong University of Technology. The internal flow uniformity of oxidation bed in the thermal reverse-flow reactor was studied experimentally, then the effects of different inlet flow rate on the flow uniformity were discussed, and the mechanism of fluid mechanics was analyzed. In addition, according to the Darcy-Forchheimer's law, the mathematical model of the flow resistance was established, which was used to calculate the inertial and viscosity resistance coefficient of oxidation bed.2) Based on the model experiment, the flow field of the cold test device was numerically simulated with the Computational Fluid Dynamics (CFD). The paper discussed the factors which influence the precision of computing results, and accomplished numerical processes which solve flow field distribution in the device by simplifying physics model, ascertaining mesh types and adjusting mesh density, choosing turbulent flow model, setting porous media model and boundary conditions. The numerical results presented a good agreement with respective experimental results. Then the effects of the structural parameters of the reactor and diversion system on the flow uniformity were investigated deeply.3) On the basis of the above, the flow uniformity was studied in the thermal flow-reversal reactor with the capacity of 60000m3/h numerically. By improving the diversion system, some optimization measures were taken to make the flow field uniform.