Study of High-Pressure Sirocco Fan Using Double Reversal Rotors

A sirocco fan using double reversal rotors in which inner rotor is settled inside the sirocco fan rotor and each rotor rotates in an opposite direction was proposed for the purpose of higher pressure and more compact structure of a sirocco fan. If the high discharge pressure is obtained with the adoption of the double reversal rotors, it could be used for various purposes. Pressure coefficient of a sirocco fan with double reversal rotors is higher than conventional sirocco fan which is 2.5 times of conventional one and the maximum efficiency point of double reversal rotors shifts larger flow rate than a conventional sirocco fan. On the other hand, it was clarified from the flow measurement results that circumferential velocity component at the outlet of outer rotor of double reversal rotors becomes larger than a conventional one. In the present paper, the performance of a conventional sirocco fan and a sirocco fan with double reversal rotors are shown and the internal flow field at the outlet of outer rotor of both cases is clarified. Then, the effect of different kind of double reversal rotors on the performance and internal flow field is investigated and high performance rotor design of it would be discussed.