The traditional jet fans have equipped with the tandem impellers and the exclusive motors, and such designs are associated with the expensive initial cost. This serial research proposes how to simplify the fan profile for reducing the initial cost without the performance deteriorations. The paper discusses the effects of the hub profiles installed in the traditional/commercial jet fan, on the performances in the several type single-stage work. The hub with the long tail corn gives the best efficiency, and not only the stay vanes but also the cooling fins deteriorate more or less the performances, accompanying the impeller works as follows. The efficiency at the reverse rotation of the original impeller, namely at the flow condition running from the outlet to the inlet, is doubtlessly lower than one at the original rotation. The unique cascade, where the leading and the trailing edges of the blade are alternated in the tangential direction, was prepared in anticipation of improving the performances. These results advise the desirable profile of the jet fan equipped with the single-stage impeller, and the numerical simulation provides the optimum blade profile for the bidirectional flow.
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