Translated Abstract
Multi-blade centrifugal fans have been widely used in air conditioners, range hoods, radiators and other household appliances due to its low noise, small size, large flow coefficient, and high pressure factor. With the improvement of people＇s living standard, the level of noise has been paid extensive attention. Therefore, it is of significance to reduce the noise of multi-blade centrifugal fan to improve people＇s living environment.
Firstly, the numerical simulation was carried out to get the flow field of the prototype fan. Secondly, the aerodynamic performance and noise measurement results of the prototype fan were obtained by the experimental. Good agreement between the simulation and experimental results shows that the numerical simulation was effective. Finally, by analyzing the flow field results of the fan, the breakthrough point of the turbulence, and the main internal noise source of the prototype fan were determined.
The present blades of the multi-blade centrifugal fan are mostly the equidistant straight structure with the inlet and exit edges both are parallel to the impeller axis. All installation angles of the blade are identical in the impeller edge but the velocity distribution of actual airflow on each edge is not uniform. In this thesis, the segmented blade was designed on the impeller inlet edge, and the optimum axial design width and radial design width of the blade were obtained. The flow rate of the fan was increased by 0.61m³/min, and the efficiency was increased by 2.04%. The analysis of the flow field of the fan show that, the segmented blade allows the air to adapt to the flow before the large angle turn, which changes the state of the flow disorder caused by rapid changes of the flow, thus improving the aerodynamic performance of the blade and the efficiency of the fan. In order to further improve the outflow of blade, a unit bionic blade of the multi-blade centrifugal fan was designed based on the wing-scanning structure of a hawk, and the multi-coupled bionic blades were designed by coupling the noise-reducing structure of the trailing edge with the front edge of the hawk wings. The results showed that the fan with the multi-coupled bionic blades can increase the flow rate by 0.62 m³/min, the maximum static pressure by 30 Pa, the efficiency by 7.8%, and reduce the noise by 1.2dB.
Translated Keyword
[Aerodynamic performance, Bionic blade, Multi-balde centrifugal fan, Noise, Numerical simulation]
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