Effect of Tip Clearance on Low Specific Speed and Low Flow Pump Performance
To establish the relationship between tip clearance and performance of low specific speed small flow pumps.By means of numerical calculation,the gap size is characterized by tip clearance width"s"and impeller outlet width"b"ratio,and the pump characteristics under different clearances are compared.With the increase of clearance,pump head and efficiency gradually decrease.Difference of head and efficiency under the maximum and minimum clearance is 15.4％and 5.5％respectively.When the clearance is small(s/b＜0.2),unstable"hump"phenomenon will occur in the head curve under small flow conditions.After s/b＞0.3,the efficiency reduction near the design conditions will increase significantly.In terms of flow characteristics,the increase of tip clearance will result in clearance flow affecting impeller flow more seriously,leading to severe secondary flow and vortex.Meanwhile,unstable flow within tip clearance can also cause energy loss.Finally,head and efficiency are decrease.The study provides a reference for the design and optimization of low specific speed small flow pump.
centrifugal pumptip clearancelow specific speedsmall flow rate
万方数据
维普
