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Our customer is a large enterprise that erects and commissions cooling towers for thermal power plants. One of their projects required them to design and install a 34ft diameter fan, a size that is normally a standard for cooling tower fans. However, due to the stringent power consumption criteria on fan, customer decided to rework the design. Uncertainty over existing thumb rules and major time, cost associated with prototyping and evaluation, led them to adopt a design-by-analysis approach.

Zeus Numerix used its proprietary fan design software, FanZ that uses Blade Element Method to estimate performance. It requires lift and drag coefficients for the airfoil section of fan, which were obtained using CFD analysis on proprietary software, CFDExpert. Finding that efficiency of first-cut fan design was not upto the required value, optimization module of FanZ was used to get the optimum twist and chord length of airfoil along the span of fan blade.

Top left: CFD result of airfoil section. Top Right: Performance prediction of fan. Bottom: Optimized fan blade design.

The optimum fan blade design was delivered to the customer in AutoCAD format. The customer went ahead with the fabrication of the recommended fan design. On commissioning the desired energy efficiency was successfully obtained.