NUMERICAL ANALYSIS ON THE CAVITATION IN AN INJECTOR ORIFICE

• Main Authors: YING-CHI CHUO, 卓英吉
• Other Authors: TSUNG-LEO JIANG
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/01946338735388985739

碩士 === 國立成功大學 === 航空太空工程學系 === 83 === PISO algorithm is adopted to calculate the flow field in a suddenly contracted injector orifice under a certain range of Reynolds numbers. In the present study PISO algorithm demons- trates to possess good numerical stability in using large time steps for steady flows. It also has well-accepted transient accuracy to be an alternative choice for unsteady flows. As far as the steady flow of the injector orifice is concerned, a re- circulation zone is predicted to occur in the vicinity of the entrance of the orifice to form vena contracta at certain Rey- nolds number. The length of the recirculation zone increases with the increasing Reynolds number. The local pressure, however, descends as the Reynolds number increases. Since cavitation occurs as the local pressure drops down to the vapor pressure, the minimum pressure in the flow field is predicted under various Reynolds numbers. In a comparision between this minimum pressure and the vapor pressure at the given operating condition, the flow condition at which and location where cavitation incepts are identified.