Effect of Axial Clearance Between Turbine and Guide Wheel on Hydraulic Performance of Mine Borehole Turbo Generator

Abstract In order to study the influence law of axial clearance between turbine and guide wheel on the performance of mine turbine generator. The three-dimensional unsteady internal flow and external characteristics of 8 kinds of turbine generator models with different coaxial clearance are calculated. The results show that: As the axial clearance coefficient between the turbine and the guide wheel increases, the pressure loss at the inlet and outlet of the guide wheel and turbine increases gradually, the torque and shaft power of the turbine are reduced, the hydraulic efficiency of turbine generator decreases gradually; The hydraulic efficiency of the turbine increases first and then decreases. Considering the external and internal flow characteristics comprehensively, the axial clearance coefficient between the turbine and the guide wheel is between 0.12 and 0.15, and the turbine generator performance is the best. It can provide some reference for the design optimization of Mine Borehole Turbo Generator.