Experimental study on the mean flow characteristics of forward-curved centrifugal fans

Abstract

Measurements have been made in an automotive HV AC blower for two different centrifugal fans. This work is directed at improving the performance of a conventional forward-curved centrifugal fan for a given small blower casing. Mean velocities and pressure have been measured using a miniature five-hole probe and a pressure scanning unit connected to an online data acquisition system. First, we obtained the fan performance curves versus flow rates showing a significant attenuation of unstable nature achieved with the new fan rotor in the surging operation range. Second, aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage for different fan operating conditions. The measurements showed that performance coefficients are strongly influenced by flow characteristics at the throat region. The main flow features were common in both fans, but improved performance is achieved with the new fan rotor, particularly in lower flow rate regions. Based on the measured results, design improvements were carried out in an acceptable operation range, which gave considerable insight into what features of flow behavior were most important.

Three-dimensional flow analysis and improvement of slip factor model for forward-curved blades centrifugal fan

“…Although a lot of experimental works have been reported for this type of centrifugal fan (Kwon and Cho, 2001 ;Sandra Velarde-Suarez et al, 1999;Raj and Swim, 1981;Kind and Tobin, 1990), few of them is helpful to validate the models for slip factor and losses because detailed data about flowfield were not provided. However, the evolution of CFD (Computational Fluid Dynamics) makes it possible to have detailed insight into the flowfield in this centrifugal fan with sufficient accuracy (Thomas Bouquet et al, 2002) .…”