| description abstract | Ambient wind has adverse impacts on the thermal-flow performances of air-cooled steam condensers (ACSCs). It is useful to understand the mechanisms of such influences so as to improve and optimize the performance of condensers. The flow fields around an ACSC at different wind speeds and directions are numerically investigated in this paper. It is found that the negative pressure region under the ACSC platform results in volumetric effectiveness reduction of the windward fans with increasing wind speed, and hot air recirculation or reversed flow in condenser cells causes a fan inlet air temperature increase. Under windy conditions, if a main building blockage effect exists, either hot air recirculation will occur, or else reversed flow may arise. The negative pressure region under the platform plays a leading role in the heat transfer effectiveness reduction. From the scale of condenser cell instead of the whole ACSC, stable backpressures corresponding to the windy conditions are forecasted by the combination of the effectiveness-NTU method and the numerical method, which makes the model closed to the true status. The increasing amplitudes of the backpressures reach, respectively, 14.3, 15.4, and 6.4 kPa at | |
