80-01: The Effect of Fan Tip Clearance on Cooling Towers Performance

One of the parameters that affect the performance of axial flow fans of induced draft cooling towers is the clearance between the tip of the fan blade and the fan stack. Fan performance in turn influences the behavior of the cooling tower as a whole. Very little full-scale information is available to indicate the magnitude of the effect of tip clearance on cooling tower performance. This paper presents test data taken on actual cooling tower installations showing the impact of fan tip clearance on overall tower performance. Such data are helpful in evaluating the economic trade-off between improved tower performance and increased costs of a more efficient air movement system.