Measurement of Loss Coefficients of Microdiffusers under Low Reynolds Number Flow

• Main Authors: Jui-Cheng Hsu, 徐瑞呈
• Other Authors: Yi-Chun Wang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/08917614761176697603

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 94 === This study aims at measuring the loss coefficients of planar microdiffusers under low Reynolds number flow as a function of divergence angle. The planar microdiffusers have a fixed slenderness ratio of 15 and the divergence angle is varied from 4。-120。. The range of the Reynolds number in the experiment is 100-2000. The flow rate is controlled by a precision syringe pump, which pushes the fluid through a section of pipeline, a reservoir, the microdiffuser, and then entering a tank. The pressure in the reservoir is measured by a precision pressure sensor and is used for calculating the loss coefficient of the diffuser. Experimental results show that the loss coefficient increases with decreasing Reynolds number. Microdiffusers with small divergence angles may have larger loss coefficients than those at large angles due to the wall frictional loss. The pressure losses of microdiffusers at large angles are primarily due to flow separation and the effects of viscous loss are very limited.