CHARACTERISTICS PREDICTION OF VANE. PUMP WITH RICH GASES CONTAINING HYDRAULIC OIL

In recent years, fuel consumption of vehicles has been remarkably improved by some cutting edge technologies (e.g., hybrid electric vehicles, non-idling systems). In-vehicle equipment is also required to improve efficiency. The vane pumps used to control power steering and transmissions must demonstrate maximum performance, even under high temperature conditions and with rich gases contained in hydraulic oil. Precise recognition of the dynamics of pump inner flow can help in the design and development of vane pumps. In this study, the 3-dimensional CFD is adopted to analyze the characteristics of inner flow dynamics of vane pumps. Since the gases contained in hydraulic oil influence the characteristics of vane pumps, the two-phase flow model with cavitation is assumed in particular. First, this CFD was verified by comparison with experimental results which were carried out at higher rotational speeds and with oil containing a high level of gas; the results showed the error of the suction flow rate could be as little as 5% or less. Internal pressure in the vane chambers was then studied to identify the relationship between the cavitation model and the contained gas ratio of the oil. The simulation results further clarified that the gas clouds deformed by pump rotation could restrict the flow of the suction ports.