Influence of hydrodynamic retarder blade angle on vortex structure

The internal flow of the hydrodynamic retarder cavity is a complex three-dimensional turbulent flow, and the evolution of vortices in its internal two-phase flow field is closely related to the generation of braking torque and the dissipation of kinetic energy. In this study, a periodic flow channel model is used to investigate the influence of different blade angles on vortex structure characteristics. The vortex structure identification method with Q criterion is employed to compare and analyze the distribution and development of the vortex structure. Particle image velocimetry (PIV) tests are conducted to observe the evolution of the vortex structure inside the retarder and validate the simulation analysis. Results show that the increase of the vortex structure scale, intensity, and transformation speed caused by the increase of the blade angle, which affects the energy dissipation and transfer of the flow field and explains the reason for the change of the braking torque. This provides a theoretical basis for the study of the braking performance mechanism and design optimization of the hydrodynamic retarder.