AN EXPERIMENTAL AND NUMERICAL STUDY OF HEATED EFFLUENT DISCHARGE IN A HORIZONTAL CROSS FLOW

Abstract

Experiments were conducted to study the behaviour of submerged buoyant jets discharged horizontally into a cross flow. The experimental investigation covered a fairly wide range of factors related to different ambient flow rates, jet velocities and jet temperatures. Both temperatures and velocities were measured extensively at nine cross- sections along the channel. The dispersion characteristics associated with various selected factors, which included the maximum temperature increment and its locus, were analyzed using the measured data. Uncertainty analysis and repeatability analysis were carried out to analyze the accuracy and reliability of the experiments. A three-dimensional numerical hydrothermal model was utilized to simulate the . thermal distribution resulting from the submerged discharge of a heated effluent into a cross flow. The mathematical model included the Navier - Stokes equations, the energy equation and the standard k-? turbulence model. These equations were discretized into finite difference forms with the hybrid central/upstream scheme. The computational procedure was based on the SIMPLE algorithm, which made use of a non-uniform staggered grid arrangement. A universal wall function was employed in the program. The heat exchange between water-air interface was also considered. The numerical model was calibrated and validated against the experimental results and the agreement was generally good. The numerical prediction also revealed some features of the highly complicated flow pattern and temperature distribution of the 3-dimensional plume in the vicinity of the jet outlet.