Improvement mechanism of wedged column on the cooling performance of vertical delta radiator

Abstract

Vertical delta radiators were widely used in dry cooling towers as the key radiator element. But the delta structure was very easy to induce large vortex between its two sides when the air was slantly flow in, which was very commonly under real natural crosswind conditions. To alleviate the adverse effect of large vortex on its adjacent cooling column radiator, one type of wedged cooling column was proposed, which was a columnar cooling tube bundle with a wedged-shaped gap. A three-dimensional (3D) numerical model for natural draft dry cooling tower (NDDCT) with vertical delta radiators was established and validated to study the improvement mechanism of wedged cooling column on the cooling performance of vertical delta radiators. Both aerodynamic field and air temperature field were compared and studied between the vertical delta radiators with wedged columns (VDRWs) and usual vertical delta radiators. It could be found that both the heat transfer temperature difference and air mass flow rate of VDRWs were greater than those usual, which could decrease the exit water temperature by 0.27 and 2.23 °C separately at no crosswind and 7 m/s crosswind. Beside, the equivalent outlet water temperature TA could decrease by 0.493 °C, which suggested that the wedged cooling column could improve the cooling performance of vertical delta radiators to some extent.