Numerical Modeling Study on Heat Dispersion of Cooling Water for Inland Power Plants.

Haiwen Zhang, Ping Ji, Yijun Zhao, Jue Yuan, Li Zeng, Xiaoli Chen

Thursday 2 july 2015

17:00 - 17:15h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 13G. Environment - Impact

Environmental hydraulics is concerned with the changes in the environment induced by human activities or by man-made structures. One of the main impacts comes from cooling water discharges from power plants. It is important to study the heat dispersion of cooling water for plant siting decision and Environmental Impact Assessment (EIA). A numerical modeling study on heat dispersion of cooling water for the purpose of site selection of inland power plants is presented in this study. A Quasi-3D hydraulic modeling by using MIKE 3 HD with flexible mesh has been carried out to simulate the distribution of temperature rise due to the cooling water discharge in rectangular channel. A series of scenarios with different ratio of width to water depth (_=B/h) and various ratio of ambient flow discharge to the cooling water discharge (_=Qa/Qo) has been simulated. Based on the modeling results, the dispersed areas of temperature rise (1, 2, 3 and 4_) have been counted. Moreover, considering the specific limit on the dispersed distance in transverse direction due to the requirement of environmental protection, the maximum dispersed distance of temperature rise in transverse direction (y) has been analyzed. It is found that, the distance (y) can be approximately described by a function of water depth (h), ratio of width to water depth (_), ratio of ambient flow discharge to the cooling water discharge(_) and the ambient Froude number (Fr=U/(gh)^0.5, in which, U is the ambient current speed). The calculated and observed distance results have been compared. The calculation match the observation well.