Numerical Simulation of Flow Field for a Whole Centrifugal Fan and Analysis of the Effects of Blade Inlet Angle and Impeller Gap

Numerical simulation of the flow field was carried out for a whole centrifugal fan to consider the interaction of three parts—inlet, impeller, and scroll. A modern optimum design method for a centrifugal fan has been presented using a computational fluid dynamics (CFD) technique to replace the conventional method. A sample fan based on the optimum design was manufactured and tested. The numerical prediction agrees well with the test data. The excellent performance of the sample fan has proved the validity of the method adopted. Moreover, the effects of the blade inlet angle and the gap between impeller and inlet on the fan performance are quantitatively analyzed. Particularly the energy loss in every passage, including the gap loss and the leakage flow rate in the gap, are discussed in detail in the paper. It is found that the blade inlet angle and the impeller gap play an important role for fan performance.