MATHEMATICAL MODELING OF THE HOT WATER DISCHARGE EFFECT ON THE AQUATIC ENVIRONMENT OF THE THERMAL POWER PLANT BY USING TWO WATER DISCHARGE PIPES

摘要

The paper presents a mathematical modeling of the discharge hot water effect on the aquatic environment of a thermal power plant by using two water discharge pipes. It is solved by using the Navier–Stokes and temperature transport equations for an incompressible fluid in a stratified medium. The numerical solution of the system of equations is divided into four stages by using a projection method approximated by the finite volume method. In the first stage, it is assumed that momentum transfer occurred by convection and diffusion where the intermediate velocity field is solved by the 5-step Runge–Kutta method. In the second stage, the pressure field is solved by using the intermediate velocity field where the Poisson equation for the pressure field is solved by the Jacobi method. In the third stage, it is assumed that the momentum transfer is carried out only by the pressure gradient. In the fourth stage, of the temperature transport equation is solved as momentum equations by the 5-step Runge–Kutta method. The obtained numerical results of the stratified turbulent flow for two water discharge pipes were compared with experimental data and with numerical results for one water discharge pipe. In the case where two water discharge pipes were used, a general thermal load in the reservoir-cooler decreases compared to the case with one water discharge pipe. Also revealed is that qualitatively and quantitatively the basic laws of hydrothermal processes occurring in the reservoir-cooler can be approximately seen in the numerical simulations.