Detailed Model Study of Pump-Approach Flows for the Lake Chicot Pumping Plant,

摘要

A 1:24 Froude-scale model of the proposed Lake Chicot Pumping Station was constructed and utilized to identify and to correct hydraulically objectionable features of the flows in the pump sumps. The model tests showed that the flows from the plant forebay generally enter the individual pump bays with a strong transverse component of velocity and produce an intense captive eddy on the lee side of each pump-bay partition wall. The transverse velocity resulted from geometric constraints imposed on the plant configuration. In order to achieve better pump approach-flow conditions trash racks with relatively deep vertical bars which functioned as turning vanes were proposed. A 1:10-scale sump model then was built to test for model-scale effects in the trash-rack tests, and an extensive study was conducted to obtain an improved sump configuration which would minimize any vortex-related problems in and around pump suction bells. The modified sump configuration has small clearance between the pump bell and sump back-wall; converging sidewalls; and a floor mounted splitter plate (vortex breaker) beneath the pump. (Author)