Effect mechanism of cooling delta aerodynamic field equalizing on the cooling characteristics of dry cooling tower

Abstract

As the key heat transfer components for large-scale natural draft dry cooling tower (NDDCT), the cooling deltas perform poorly when subjected to ambient crosswinds, thus leading to the cooling performance degradation of NDDCT. To enhance the cooling delta's heat transfer capabilities, the effect mechanisms of aerodynamic field equalizing, i.e. air equalizing, on the deltas were studied by the validated three-dimensional (3D) numerical model. For the deltas arranged around NDDCT, the aerodynamic fields, the air flow rates, and the water temperature were all analyzed for cooling columns composing deltas. By comparing the two situations with air equalizing or without in the midst of cooling delta, it could find that the air equalizing diminished the air flow rate differences between the two columns in one delta, which improved the cooling characteristics of the poorer-performing columns mostly at the delta's leeward but deteriorated those of the better-performing columns mostly at the delta's windward. With the air equalizing, the cooling characteristics of the two columns in one delta were balanced. And then the cooling characteristics of most deltas and the whole NDDCT were improved to some extent at varying crosswind speeds, which was significant for the design optimization of conventional delta-type radiators.