Numerical optimization of impeller for backward-curved centrifugal fan by Response Surface Methodology (RSM)

A numerical optimum study on three-dimensional unsteady viscous flow in a centrifugal fan with backward-curved blades was performed. The influence of the inlet angle, the outlet blade angle and blade number on aerodynamic performance of the centrifugal fan was analyzed concerning the whole impeller-volute configuration. Response Surface Methodology (RSM) based on a three-level, three -variable Box-Behnken Design (BBD) was used to evaluate the interactive effects of factors such as inlet blade angle (37°-41°), outlet blade angle (61°-65°) and number of blade (10-14) on the efficiency. The optimum factors deriving via RSM were: inlet blade angle 37°, outlet blade angle 61.7° and blade number 14. The maximum efficiency was 93.7%, under optimum conditions. The method of reliable CFD technique in combination with RSM can be effectively applied to the improvement and experiment design of centrifugal fans.