Abstract
In this paper, a commercial frost control fan was redesigned from the viewpoint of light weight design concept. A preproduced fan based on the proposal of applying the above mentioned techique was tested for comparison between them before and after redesigning, especially for the points of vibration and noise characteristics.
The vibration characteristics was clarified by use of modalysis method for both commercial and proposed fans. Natural frequency and damping ratio were obtained through this tecnical procedure. The vibration state of blade No. 1 and 2 and the fan under operating condition were distinguished. Nosise characteristics was also clarified. It showed no significant difference in noise level for both fans. The level of discrete-frequency noise was high in whole noise emitted from the tested fans. The acoustic field analysis was done by applying AI (acoustic intensity) method, and an idea for reducing noise level was proposed.
