Design and Numerical Analysis of Guide Vane for the In-Line Fan

• Main Authors: Yu-neng Wang, 王昱能
• Other Authors: Sheam-chyun Lin
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/74215900780877244865

碩士 === 國立臺灣科技大學 === 機械工程系 === 96 === The major function of the in-line fan inside a duct is to offer the sufficient static pressure for transporting the fresh air from air conditioner to duct outlet. This research intends to design the guide vanes at the fan discharge to remove the air spin and convert some of the energy losses into additional static pressure; thus, the in-line fan can overcome the system resistance more smoothly inside ducts. First of all, an in-line fan with a square housing is chosen to execute and analyze the numerical flowfield simulation at its maximum-efficiency point. Then, an extra motor housing is proposed to eliminate the vortex and reversed flow around the motor based on the flow patterns observed from the CFD results. This modification not only enhances the static pressure by 8.6% at its peak efficiency, but also creates a stable incoming flow at the leading edge of the guide vane. Thereafter, two guide-vane configurations, 8-blade and 12-blade, are constructed according to the flow patterns around the motor housing. Nevertheless, the numerical result shows that fan performance is not improved owing to the stronger vortex development caused by the guide vanes at the housing corner. Hence, width modification on the guide vanes is applied to diminish the vortex strength and thus generate an extra 2% pressure increase at the peak efficiency point. In summary, the best guide-vane design considered in this study results in a 3.5% increase on the maximum flow rate and a 10.8% pressure enhancement at its operation point compared to those of the original in-line fan.