Wind tunnel experimental study on the influence of super-large natural ventilation cooling tower on the flow and diffusion of pollutants

In this paper, a wind tunnel experiment was carried out to study the atmospheric flow and pollutant diffusion around a super-large natural ventilation cooling tower of a nuclear power plant. Considering the effect of the natural ventilation of the cooling tower, with the chimney as the center, X-type hot-wire probes were used to measure the average flow field and turbulence structure of the atmosphere around the cooling tower and other complexes, and pollutant diffusion studies were carried out by tracer experiments. The results show that the super-large natural ventilation cooling tower and its thermal plume emission have a significant effect on pollutant flow and diffusion, changing the trajectory of the plume. When the chimney is located upwind of the cooling tower, some pollutants are emitted secondly due to the entrainment effect through the cooling tower when the plume passes through the natural ventilation cooling tower, regardless of whether or not the cooling tower is operating. Compared with the cooling tower that does not operate, the thermal plume and natural ventilation effects generated by the cooling tower during operation cause the plume dispersion range to widen, the maximum concentration to decrease, and the impact on vertical diffusion to be more significant than that on horizontal diffusion.