EFFECT OF POWER PLANTS OUTFALL SHAPES m ON THE THERMAL POLLUTION INTO OPEN CHANNEL

Abstract

High temperature has a severe effect in chemical and biological processes inside water. Thermal discharges from industrial processes and power generation can cause temperature increases in the receiving water of 10C or more. The rate of chemical reaction is doubled for each 10C temperature rise, that affect the overall productivity of water species.

There are two ways of discharging hot water that are surface discharge and submerged discharge. Submerged discharge is a way to discharge hot water by using diffusers that give good mixing in the receiving zone. The two types of the submerged diffusers are the single port and the multiport diffusers. The multiport diffusers may be unidirectional, alternating, or staged diffusers.

The experiments were performed in a rectangular flume. A pump raised the cold water from the River Nile to the boiler to fill it up and also pumped the hot water from the boiler to the flume through pipeline. The hot water flow was measured by using two magnetic flow meters through the length of the pipes from the boiler to the flume. The depth of the flow in the flume was controlled using an adjustable gate at the end of the flume. The flow in the flume was fully developed at the location of the inlet diffuser. In this study. an experimental set up was employed to test 4 types of submerged multi-port diffusers outlets by changing their ports shape as follow: - Diffuser shape - Nozzle shape - Circular shape - Square shape