| The performance of centrifugal fans generally installed in the pipeline system, not only depends on the centrifugal fan itself, but also closely relates to the pipe structure. According to statistics,60%of the centrifugal fan performance in the existing pipe system cannot meet the requirement.In this paper, experimental study and numerical simulation were conducted to understand the effect of the centrifugal fan performance (9-26No4A) with90°inlet bent pipe which connected different length of straight pipes. The result of the experiments showed that, the performance of the fan directly connected bent pipe was not changed; the performance of the fans with D-straight pipe (D is the inlet diameter of the fan) and2D-straight pipe had a noticeable decline under large mass flow rate and a slight drop at low mass flow rate; the performance of the fan was improved with4D-straight pipe. The internal flow fields of the four models were numerically simulated using Fluent software and the influence on the centrifugal fan was analyzed. The result of the simulation showed that, there was little difference between the flow field of the fan directly connected bent pipe and the flow field of the standard fan; the airflow of the fan with D-straight pipe,2D-straight pipe and4D-straight pipe were different and the downstream backflow of the bent pipes was formed, which could weaken the inlet flow field and decline the performance of the centrifugal fan. |
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