The Effect of Half Vane Diffuser on the Noise Generated from a Centrifugal Fan

Abstract

In this paper an experimental study is conducted to investigate the influence of a half vane diffuser on the noise behavior of a centrifugal fan, used in a vacuum cleaner. The diffuser vane height h/b is varied as follows: 0 (vaneless), 0.2, 0.4, 0.6, 0.8 and 1.0 (full vane) at two diffuser inlet radii R3/R2 = 1.03 and 1.07. The experiments were carried out on a high speed centrifugal fan. The sound pressure level (SPL) and pressure rise of the centrifugal fan were measured in a semi‐anechoic chamber. The fan flow coefficient was in the range of 0.02 to 0.14, and the rotational speed of the impeller varied from 20,000 to 35,000 rpm. The experimental result shows that by using a half vane diffuser, the sound pressure levels are respectively reduced by 5.5 dB(A) and 3.5 dB(A) at R3/R2 = 1.03 and 1.07. Meanwhile, the half vane diffuser improves the fan performance and extends the flow range. The optimal value of the half vane height is about 0.6 times of the diffuser width.

Experimental investigations on the performance and noise characteristics of a forward-curved fan with the stepped tongue

“…[13][14][15] Cau et al 16 argued that a severely distorted primary flow with early flow separation on the suction side at both low and design flow rates occurs due to the poor 1 State-Province Joint Engineering Lab of Fluid Transmission System Technology, Zhejiang Sci-Tech University, Hangzhou, China 2 design of the flow channel in these fans. Zhang et al 17 conducted an experimental study on a centrifugal fan by a half vane diffuser which can improve fan performance and reduce noise. Sorguven et al 18,19 calculated the acoustic sources of a forward-curved fan using the boundary element method.…”