Analysis of the Flow Field Characteristics and Blade Wheel Strength of Variable Speed Hydrodynamic Coupling under Full Filling Condition

The variable speed hydrodynamic couplings are widely used in soft-starting of scraper conveyor and belt conveyor in coal mine machinery. In order to analyze the internal flow field, torque characteristics and blade wheel strength of the hydrodynamic coupling under full filling condition, the flow field model of pump and turbine was established. The numerical simulation of internal flow field in the hydrodynamic coupling was carried out by using the computational fluid dynamics (CFD) software CFX. The characteristics of velocity streamline and pressure field distribution in 5% relative slip between pump and turbine under full filling condition was analyzed, and the torque characteristics of hydrodynamic coupling at different speed ratios were obtained. Finally, based on the one-way fluid-solid interaction theory, the finite element strength model of the blade wheel was established, the equivalent stress distribution and overall deformation state of the blade wheel under extreme working condition were obtained. The results show that the internal flow state and torque characteristics of hydrodynamic coupling can be predicted by the numerical simulation. The simulation results provide a technical support for the blade wheel strength analysis and control system design of the variable speed hydrodynamic coupling. Besides, the finite element strength analysis provides a theoretical basis for the structural optimization design of the hydrodynamic coupling.