Influence of Staggering and Interdistance on Performance of a Low-Speed Counterrotating Axial Fan

Abstract

Counterrotating axial fans (CRF) are being adopted in air ventilation to meet the demand for a higher pressure head and swirl-free discharge. This experimental and numerical study is aimed at investigating the influence of blade staggering and interdistance between the front rotor (FR) and the rear rotor (RR) on the aerodynamic performance of a low-speed CRF. The latter was built from a baseline single-rotor fan (SRF) using the same blade profiles. The results reveal the conversion of a large part of the swirl flow into a static pressure, and the total-to-static isentropic efficiency is improved under certain setting parameters of the FR and RR. Moreover, the counterrotation seems to reduce the aerodynamic loading in both rotors blades and to allow a stable operation over a broader flow-rate range. Among the examined configurations of CRF, the optimal has been identified.