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Performance Investigation of Bell Mouth of the Multi-Blade Centrifugal Fan in Floor Standing Air-Conditioner

Three types of bell mouth with the inward bell mouths whose exit diameter are larger than the impeller inner diameter of multi-blade centrifugal fan used in floor standing air-conditioner are investigated by using the numerical simulation method. Three bell mouths are as follows: The first type of bell mouth is the inward inlet used in the original air-conditioner. The second type is the inward inlet whose axial height is larger than the first type. The third type is the new mold line inward inlet with smaller slope angle than the first type. Calculation results show that the later two type bell mouths can help to improve air volume flow ratio, reduce the vortex in the back of volute exit and increase the air volume flow rate of 6.8 % and 4.2% respectively. The experimental verification was conducted for the simulation results and the experimental results shows that the air volume rates increase 4.7 % and 3% respectively, the level of noise is constant. The entire performances of the two types are both improved.