Abstract:
The single-arc blades of a multi-blade centrifugal fan used in a range hood was modified to double-arc designs within a diameter limitation. The effects of acceleration and deceleration double-arc blades on fan performance were studied, and the performance advantages of both single and double-arc blades were compared and analyzed. The fan pressure and efficiency of different blade schemes were numerically predicted through computational fluid dynamics. The optimal value range of the inlet angle of the single-arc blade should be preset based on the minimum-impact-loss design with an attack angle of 20.0°-30.0°. Considering comprehensively the fan pressure and efficiency, the optimal value of the outlet angle of the single-arc blade is between 165.0° and 173.0°. For single-arc blades with poorly matched inlet angle, the use of deceleration double-arc blades can increase the fan pressure and efficiency. However, for the single-arc blades that are already optimized, only retrofitting to the acceleration type could further increase the fan pressure, but the efficiency will slightly decrease. Compared with the single-arc blades with the same blade angles, the working load of the acceleration double-arc blades moves upstream, and the secondary separations on the blade suction surface are also inhibited. The blade passages are more difficult to be penetrated by the volute tongue reverse flow, which benefit the fan aerodynamic performance under low-flow conditions.