Experimental Flow Studies With the Dual-Screen Cooling Water Intake Assembly ("Riser") for the James H. Campbell Electric Power Generating Plant, Unit No. 3

Abstract

Flow characteristics inside and outside of a dual-screen cooling water intake assembly ("riser") for the James H. Campbell Unit No.3 were observed and measured in hydraulic models at scales of 1:3 and 1:12. Risers consist of dual cylindrical screens with horizontal axis and solid endplates mounted on a T-assembly which is supported by a 3.5 ft diameter vertical withdrawal pipe. Pressure losses within the assembly, approach flow velocity patterns and approach flow velocities on the screen surface were investigated. A total headloss coefficient of 4.6 resulting in an equivalent full-scale headloss of 8.0" of water at a withdrawal rate of 29.44 ofs through the assembly was measured in the model. Flow patterns towards single and multiple risers were observed by dye tracing techniques. Approach flow velocities were measured on the surface of the 1: 3 scale riser model. The highest velocities were found near the center of the screen and the lowest ones near the projecting endplates. Maximum local velocities exceeded calculated average velocity by about 30 per cent.