Background: Using viscosity of fluid between friction pairs to transmit power is called the
Hydro-viscous Drive (HVD), which has obvious energy-saving effects on soft start and speed regulation
in large belt conveyors, fans, and pumps. Therefore, it is of great practical significance to conduct the
HVD technology research to improve its performance. In some conditions, cavitation in the oil film is
generated, consequently affecting its transferred torque.
Objective: The purpose of this paper is to study comparatively the oil film characteristics of both single
phase and multi-phase flow, and to reveal the cavitation mechanism of oil film and its effect on transferred
Methods: In this paper, we build a 3D model of oil film between friction pairs to study the characteristics
of both single phase and multi-phase flow of the oil film through using the mixture model in ANSYS
Fluent. The distribution of pressure field, temperature field, and torque transferred by the oil film
are investigated by using the CFD technology.
Results: It is found that distribution of pressure and temperature of the oil film are almost similar in
single phase and multi-phase models. However, the physical phenomena at the outlet of the oil film is
entirely different. For multi-phase simulation of flow with cavitation, we first obtain the volume fraction
of air bubbles at rotation speeds of 500, 1000, 2000, 3000, and 4000 revolutions/min. With the increase
of the rotation speed, the volume fraction of air bubbles increases, and their maximum value becomes
even greater than 10%. Current and future developments of the HVD technology are finally provided to
improve the current HVD technology and fulfill its theoretical basis.
Conclusion: Due to oil film cavitation, the torque transferred by the oil film is no longer linear with the
rotation speed; its value decreases gradually. These results are important for the study of HVD and its
applications; they shed a new light on the mechanism of power transmission through oil film in the presence
of cavitation. This paper also can provide a theoretical basis for the cavitation study and its effect
on transferred torque by addressing recent patents and scholarly articles on the subject of design, control
and application of such systems.