Efficiency of Pumping from Small Circular Sumps

by Ali M. Shahroody,
John R. Davis,

Serial Information: Journal of the Irrigation and Drainage Division, 1964, Vol. 90, Issue 1, Pg. 1-8

Document Type: Journal Paper


Efficiency and minimum safe submergence of a 4-in. vertical turbine tail-water recovery pump in a circular pump are affected by side clearance and inflow velocity, but not by bottom clearance. Highest pump efficiency was attained in laboratory tests with a bottom clearance of either 0.5 D, D, or 2 D; a side clearance of 2 D or greater; and an inflow velocity of 1 fps. Minimum safe submergence of approximately 9 D is required to avoid vortex formation; however, lowest values of minimum safe submergence were observed at small side clearances. Reductions in normal pump efficiency as a result of reduced side clearance or increase inflow velocity were most pronounced at the low rate at which peak efficiency is normally attained. Such reductions averaged approximately 2%, with a maximum loss in efficiency of 4.6%.

Subject Headings: Safety | Submerging | Pumps | Inflow | Fluid velocity | Pumping tests | Turbines | Tailwater

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