Abstract
Isolated centrifugal fans are widely utilized in ventilation systems due to their compact design and high efficiency. Enhancing their aerodynamic performance is crucial for energy conservation and emission reduction. Current theoretical research on this fan type predominantly focuses on blade structure. In contrast, aerodynamic studies of the impeller inlet region remain comparatively underdeveloped. This investigation systematically examines how clearance gap between the impeller shroud and inlet duct affects fan aerodynamic performance. The gap was modified by altering the shroud flare. In this paper, an investigation on the differences in the aerodynamic performance of fans caused by gaps is conducted using computational fluid simulation. The flow field characteristics and performance differences corresponding to various gaps under design operation point were quantitatively analyzed. The research reveals an inflow phenomenon within the gap region, where streamlines migrate from the external flow field into the internal flow field of the fan. This finding indicates that, for the isolated centrifugal fan under investigation, the flow behavior in the gap region deviates from the assumptions of classical leakage-flow theory. These results help to elucidate the underlying physical mechanisms governing the gap flow in this specific configuration and serve as a reference for further studies on flow characteristics in analogous geometries.
Get full access to this article
View all access options for this article.