Research on braking performance calculation model of two-phase flow in hydraulic retarder cascade

To accurately predict the brake performance of vehicular hydraulic retarder under oil partially filled condition, two math models were built based on different internal two-phase flow assumption. The braking torque of the hydraulic retarder was calculated using the mixture-density method or gas-hydraulic separating method. Compared with the experimental data obtained under oil fully filled condition, the calculation error is less than 5%. It is found that the separating method is more accurate in theory and the mixture method is simpler in practice.