THERMAL POLLUTION OF A THERMAL POWER PLANT WITH ONCE-THROUGH COOLING SYSTEMS: A NUMERICAL STUDY

Abstract

A two-dimensional numerical model was proposed to simulate the thermal discharge from a power plant in the Republic of Serbia. The impact of the Nikola Tesla B thermal power plant on the Sava River was considered. This thermal power plant uses a once-through cooling system. A two-dimensional model was developed in the Gambit program. This model was later employed in numerical simulations using the Ansys Fluent software package. Flow parameterization was performed to determine the optimal flow of the Sava River. Four scenarios were considered, where scenario 1 represents a flow ratio of the discharge channel and the Sava River of 3% and scenario 4 a flow ratio of 12%. With the appearance of increasing droughts, the flow of rivers also decreases. As the river flow decreases, the ratio of discharge channel and river flow increases. The analysis will show that the higher this ratio, the greater the negative impact on the living world in the river. Namely, there is an increase in the heat load of the river. In the numerical simulations, the initial river temperature was taken as the arithmetic mean temperature in the summer months for the previous five years, before reaching the Nikola Tesla B thermal power plant itself. That temperature amounts to 23.1°C. When scenario 1 is compared to scenario 4, one can notice that by changing the flow of the Sava River and for the same inlet temperature, the river temperature is higher for scenario 4 at the distance of 2000m after the discharge.