Numerical Investigation Of Centrifugal Fan With Long-short Blade

Centrifugal fan with short blades is applied both in and out of country, especially, now it is applied more widely for the pursuit of high efficiency. But long-short centrifugal fan is merely used in our country, without more systematic and deep study. The forms of short blades in impeller with long-short blades are various, but the sum can be summed up in four aspects:1, the effects of the length of short blades on the performance of fan;2, the effects of the location of the short blades on the performance of fan;3, the effects of installation angle of the short blades on the performance of fan;4, the effects of the number of the short blades on the performance of fan.The true flow and flow lost were outlined in this paper. In order to investigate the effects of the short blades on centrifugal fan, numerical investigations were performed for9-26№10D and JMF№-4.3A fan models with short blades. RNG-k-ε turbulence model and SIMPLEC algorithm was used to investigate the effects of the length, the circumferential position, the installation angle of short blades and the number of the blades on the performance of fan.In order to compare easily, the results were made into characteristic curves. The results show that, to forward-curved centrifugal fans, the length of short blades mainly affects the ability to do work, the circumferential position affects both pressure and efficiency, and the installation angle mainly affects little fan efficiency; but to backward-curved centrifugal fans, the length of short blades affects the ability to do work and efficiency, the circumferential position affects both pressure and efficiency, more on efficiency and the installation angle affects the performance of fan little.