Numerical simulation of flow interruption in hydromutic coupling to reduce residual torque

Introduction. At the moment the hydraulic brake is turned off by closing the valves, most of the liquid is ejected from the cavity into the vehicle’s cooling system, however, part of the liquid with steam remains in the flow path and when the impeller rotates, a braking torque is created, which reduces the efficiency of the machine and reduces the transmission efficiency. To prevent the formation of residual braking torque, flow interrupters are used that do not allow the fluid to fully circulate in the fluid coupling cavity, thereby removing the negative effect. The object of the study is a hydraulic clutch with partial filling of the flow path used as part of the auxiliary brake system of a car.

Objective The purpose of this paper is to compare two flow interruption systems, assess applicability, and determine the range of effective operation of each system.

Methodology and methods. The finite volume method was used to study two systems for interrupting the flow in a fluid coupling with partial filling.

Results and scientific novelty. The effectiveness and applicability of two flow interruption systems for reducing the residual braking torque in a disconnected hydraulic brake has been evaluated. The distributions of the braking torque, the average circulation speed, as well as the circulation speed in the section for a hydraulic brake with partial filling without flow interruption, using shutter-breakers, as well as for several positions with longitudinal separation of the wheels, are obtained.

Practical significance. The considered systems for interrupting the flow in a fluid coupling with partial filling showed a significant decrease in the residual braking torque. However, the greatest efficiency in a wide range of rotational speeds, compared with the calculation without interruption of the flow, was shown by curtain-breakers, which is probably caused by a large decrease in the circulation rate due to additional resistance.

1. ANSYS Fluent Theory Guide // ANSYS, Inc., 275 Technology Drive Canonsburg, PA 15317, 2013. [Electron. resource.]

2. Li Airong ; Zhu Yanxia ; Wang Feng Source: International Technology and Innovation Conference 2006 (ITIC 2006), 2006 p. 919 – 922

3. Xuesong Li, Xiusheng Cheng, Liying Miao and Zhonghua Liu, "Numerical analysis on internal flow field of a hydraulic retarder," 2009 International Conference on Mechatronics and Automation, 2009, pp. 3710-3715, doi: 10.1109/ICMA.2009.5246531.

4. Landau LD, Lifschitz EM Theoretical physics in 10 vol. T. 6: Hydrodynamics. M.: Fizmatlit, 2015.

5. Labuntsov D.A., Yagov V.V. Mechanics of two-phase systems: Textbook for universities - M.: MPEI Publishing House, 2000, 374 pp.

6. Wilcox D. C. Formulation of the k-ω Turbulence Model Revisited//AIAA 2007 1408, 45th AIAA Aerospace Sciences Meeting and Exhibit. Reno, Nevada. -2007.

7. Gavrilenko B.A., Minin V.A., Olovnikov L.S. Hydraulic brakes. M.: Mashgiz, 1961. 244 p.

8. Stesin S.P., Yakovenko E.A. Blade machines and hydrodynamic transmissions. M.: Mechanical engineering, 1990. 240 s

9. Wolf M. Hydrodynamic couplings and transformers. Publishing house "Engineering," Moscow 1967 - 319 p.

10. L.Rai, M.Fiehig, N.K.Mitra ,1997, Numerical Analysis of Turbulent Flow in Fluid Couplings. Journal of Fluids Engineering, Vol. I 19, pp.569-576.