The influence of cross-winds on the performance of natural draft dry-cooling towers.

[摘要] The effect of cross-winds on the performance of natural draft dry-cooling towers is studied bymeans of isothermal model tests, a numerical simulation and full scale measurements. Theaction of the wind on such towers is found to be complex and is influenced by a number ofdifferent parameters including the wind speed, the shape of the approaching wind profile, theinlet diameter to the inlet height ratio of the tower, the tower height, the shape of the towershell, the pressure loss coefficient of the heat exchangers and the amount of heat rejected by thetower. For a horizontal arrangement of the heat exchangers the wind effect on the tower isshown to be strongly dependent on both the shape and pressure loss coefficient of the towersupports.In practical cooling towers the heat exchangers are either arranged horizontally in the inletcross-section of the tower or vertically around the circumference of the tower and the windeffect is found to be dependent on the particular layout. The wind effect on a tower isfurthermore found to increase if the heat exchangers are arranged in the form of A-frames.Additional reductions in the heat rejection rate of the tower are caused by a non-uniform airtemperature distribution inside the tower and flow distortions through the heat exchanger.Significant reductions in the wind effect on a cooling tower can be achieved by installingwindbreak walls below the heat exchangers if the latter are arranged horizontally in the towerinlet.

[发布机构] Stellenbosch University