| The paper presents the redesign study of the multi-blade centrifugal fan for the air freshing machine. Multi-blade centrifugal fan is not only the key part of the air freshing machine but also is applied widely in air-conditioner and ventilation for cooling wiring. The aim of this paper is to improve the efficiency of the fan, increase the quantity of air, but reduce the yawp (or keep the yawp) of the air freshing machine.Firstly, analysis and test have been carried out to assess the prototype of air freshing machine and its forward multi-blade centrifugal fan. Secondly, based on the analysis of the traditional design method of the multip-blade centrifugal fan proposals are made on the uncertainty of the tradition method for the selection of construct parameters, variety scheme due to the uncertainty, and a great deal of work needed to find out the optimal design scheme. This paper provides the advanced design scheme: (1). applying biquadratic bezier curve to frame the blade model line with addition of NACA0012 aerofoil;(2). grids layout in the helishell to streaming the flow and reduce the vortex loss;(3).the optimization applied on the length of snail tongue and the number of the blade. Abundant numerical simulations have been employed to help to Compare and select the optimal scheme. Finally, experimental test has been carried out on the air freshing machine and its centrifugal fan separately. Satisfied agreement has been achieved on the numerical results and experimental dates. As a consequence, comparison of the testing results of the improved fan with the prototype shows that the improvement of the performance. |
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