Hydraulic retarder is one of main auxiliary braking devices of the vehicle. When the vehicle is braking, a great pressure from high-speed fluid is received by hydraulic retarder blades. It is difficult to predict rational hydraulic retarder strength, owing to the complexity of the internal flow of oil. An optimal calculation way of hydraulic retarder strength is proposed based on CFD and FEA, concluding a reasonable result.
The 3-D model of hydraulic retarder is built in the general CAD software. The model of fluid passage is extracted, according to the condition when the whole flow passage is filled with oil, and imported to CFD software. The inner flow field of hydraulic retarder is analyzed and the hydraulic surface pressure distribution of the hydraulic retarder blade is obtained at the highest rotary speed of turbine wheel.
The pressure distribution is processed by the mathematical analysis software MATLAB, and the pressure data which can be recognized by the FEA software ANSYS are exported. The 3-D model of hydraulic retarder is imported to ANSYS and meshed to generate the FEA model. The prepared pressure data are loaded on the surface of the hydraulic retarder blades. The blades' strength, deformation and Von Mises stress are obtained after solution. Meanwhile, the modal analysis of the FEA model is solved in order to get the natural frequency, vibration mode of each modal and the greatest deformation of resonance.
Through the comparative strength and modal analysis of several groups of hydraulic retarder with different blade inclination and thickness of blades, an optimal form of blades design is obtained, and a theoretical basis for modifying design of hydraulic retarder is presented in this paper.