A performance enhancement of a natural draft dry cooling tower in crosswind via inlet flow field reconstruction

摘要

With the wide utilization of a natural draft dry cooling tower (NDDCT) in power generation in arid areas, the degradation of its performance under crosswind conditions is increasingly concerned. Based on the influencing mechanisms of the crosswind, the paper reconstructs the destructed inlet flow field with a labyrinth structure. The effect of the labyrinth structure is firstly assessed by means of a verified computational fluid dynamics (CFD) model. Then, on the basis of CFD results, the labyrinth structure is further optimised by adopting a quantification method using a flow loss factor (FLF). Numerical results revealed that the proposed flow field reconstruction approach could increase the ventilation rate of a NDDCT by 62% under high speed crosswind condition, correspondently reducing the overall coal consumption by 23,100-33,000 t annually for a 660 MW coal-fired unit. Moreover, the negative effect of the crosswind on the performance of a NDDCT could be reversed to a positive one. The numerical results are well validated by the modelling experiments conducted in a wind tunnel. (C) 2018 Elsevier B.V. All rights reserved.