Shaft power matching and performance prediction for contra-rotating axial flow fans

For that study, the authors have performed a numerical simulation of the flow field for a design of contra-rotating axial flow fans (CRAFF). The performance prediction was then validated by test data.A guideline for shaft power matching is presented too. Finally a comparison of the blade pitch angles obtained from the guideline with those obtained form the numerical simulation have been carried out for six designs of CRAFF. The deviations from the optimum obtained by CFD are within 2. That means the guideline is correct and can save a lot of time and money.