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Numerical Study of Flow Cavitation
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English
Abstract
With the progress of super computers in recent years, a number of studies on “Computational Fluid Dynamics” (CFD) have been carried out, and various schemes for Navier-Stokes equations have been presented. Similar methods have also been applied to automotive engineering - aerodynamics, for exampre - in order to determine flow phenomena.
In this paper, the application of numerical simulations to the flow cavitation that occurs in some part of orifices in the vehicle hydraulic system, will be discussed. Authors have developed a CFD program for the clarification of flow phenomena in such orifices. Using the relationship between calculated results and measured results of noise levels in such orifices, a new method for estimation of the occurrence of flow cavitation has also been developed. As a result, a new orifice configuration capable of preventing the cavitation has been designed.
VARIOUS ATTEMPTS have been made to determine flow phenomena by means of numerical simulations, which are difficult to determine by measurements. Many papers related with this issue, however, have dealt only with the verification of accuracy of simulations in comparison to measured results, without practical applications to design needs.
Under this study, CFD is applied to the problem of noise in orifice that presumably occurs due to the cavitation in the vehicle hydraulic system. A stable orifice mounted in the steering gear box of a power steering system is shown in Fig.1. Noise is found in the orifice, but it is very difficult to determine the flow phenomena in the orifice by measurement because of the high pressure and extremely small size. Thus, the mechanism of the noise reduction by the modification of the orifice geometry from one-phase to three-phase has not been clarified. Experimental studies [1], [2],and [3] have been reported,but discussions focused only on the variation of cavitation phenomena, due to the difference in the geometry of orifice, without determination of flow phenomena.
This study thus aims to clarify the mechanism and to find an effective countermeasure for the noise problem with determination of flow phenomena.
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Citation
Horinouchi, K., Yonekawa, T., Ito, S., and Kobayashi, H., "Numerical Study of Flow Cavitation," SAE Technical Paper 900819, 1990, https://doi.org/10.4271/900819.Also In
Emerging Technologies in Vehicle Cae and Structural Mechanics
Number: SP-0820; Published: 1990-02-01
Number: SP-0820; Published: 1990-02-01
References
- Inamura Y. Hibi A. Ichikawa T. “Caviration in Oil hydraulic restrictor” Japan Hydraulics & Pneumatics 7 6 341 1975
- Ichikawa T. Hibi A. Iwase N. “Cavitation and Noise of Orifices in Hydraulic System” Japan Hydraulics & Pneumatics 13 6 411 1982
- Ichikawa T. Hibi A. Inoue K. “Cavitation in two-dimentional Oil Hydraulic Choke” Japan Hydraulics & Pneumatics 15 7 545 1984
- Satofuka N. Morinishi K. “Computation of Two-Dimensional Transonic Cascade Flow Using A New Navier-Stokes Solver” AIAA-86-1981
- Kawamura T. Takami H. Kuwahara K. “Computation of High Reynolds Number Flow around a Circular Cylinder with Surface Roughness” AIAA-84-0340 1984