On the Design Method of Noise Reduction of Centrifugal Fan

2012 ◽  
Vol 487 ◽  
pp. 520-524
Author(s):  
Li Xia Peng
Keyword(s):  
Noise Reduction ◽  
Reduction Method ◽  
Design Method ◽  
Noise Generation ◽  
Centrifugal Fan ◽  
Centrifugal Blower

The application of centrifugal fan is wide, but the huge noise can pollute the environment. This paper will discuss the mechanism of centrifugal blower noise generation, and put forward noise reduction method in designing centrifugal blower creatively, thus can solve the problems effectively.

Design of an induction machine with damper windings for noise and vibrations reduction

2019 ◽  
Vol 38 (4) ◽  
pp. 1253-1262 ◽  
Author(s):  
Gregory Bauw ◽  
Bertrand Cassoret ◽  
Olivier Ninet ◽  
Raphael Romary
Keyword(s):  
Noise Reduction ◽  
Pulse Width Modulation ◽  
Reduction Method ◽  
Design Method ◽  
Induction Machine ◽  
Content Type ◽  
Density Reduction ◽  
Three Phase ◽  
The Impact ◽  
Damper Winding

Purpose The purpose of this paper is to present a design method for induction machines including a three-phase damper winding for noise and vibrations reduction. Design/methodology/approach In the first part, the principle of the damper winding is recalled. The second part presents the iterative design method which is applied on a 4-kW pulse width modulation (PWM)-fed induction machine to study the impact of the additional winding on the geometry. In the third part, the finite-element method is used to validate the designed geometry and highlight the harmonic flux density reduction. Finally, some experimental results are given. Findings The study shows that the impact of the additional three-phase winding on the geometry and weight of the machine is low. Moreover, the proposed noise reduction method allows one to reduce the total noise level of a PWM-fed induction machine up to 8.5 dBA. Originality/value The originality of the paper concerns the design and characterization of a three-phase damper winding for a noiseless induction machine. The principle of this proposed noise reduction method is new and has been patented.

Noise‐reduction method for noise‐affected voice channels

1995 ◽  
Vol 98 (4) ◽  
pp. 1836-1836 ◽  
Author(s):  
Klaus Linhard
Keyword(s):  
Noise Reduction ◽  
Reduction Method

Noise Reduction Analysis of Electronic Device Cooling Fan With Duct and Its Application Under Variable Working Conditions

2021 ◽  
Author(s):  
Zonghan Sun ◽  
Jie Tian ◽  
Grzegorz Liśkiewicz ◽  
Zhaohui Du ◽  
Hua Ouyang
Keyword(s):  
Noise Reduction ◽  
Working Conditions ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Reduction Method ◽  
Axial Flow ◽  
Pressure Level ◽  
Inlet Flow ◽  
Cooling Fan ◽  
Inlet Duct

Abstract A noise reduction method for axial flow fans using a short inlet duct is proposed. The pattern of noise reduction imposed by the short inlet duct on the axial flow cooling fan under variable working conditions was experimentally and numerically examined. A 2-cm inlet duct was found to reduce tonal noise. As the tip Mach number of the fan increased from 0.049 to 0.156, the reduction in the total average sound pressure level at 1 m from the fan increased from 0.8 dB(A) to 4.3 dB(A), and further achieved 4.8 dB(A) when a 1-cm inlet duct was used. The steady computational fluid dynamics (CFD) showed that the inlet duct has little effect on the aerodynamic performance of the fan. The results of the full passage unsteady calculation at the maximum flow rate showed that the duct has a significant influence on the suction vortexes caused by the inlet flow non-uniformity. The suction vortexes move upstream to weaken the interaction with the rotor blades, which significantly reduces the pulsating pressure on the blades. The sound pressure level (SPL) at the blade passing frequency (BPF) contributed by the thrust force was calculated to reduce by 36 dB at a 135° observer angle, reflecting the rectification effect of the duct on the non-uniform inlet flow and the improvement in characteristics of the noise source. The proper orthogonal decomposition (POD) of the static pressure field on the blades verified that the main spatial mode is more uniformly distributed due to the duct, and energy owing to the rotor-inlet interaction decreases. A speed regulation strategy for the cooling fan with short inlet duct is proposed, which provides guidance for the application of this noise reduction method.

scholarly journals NOISE REDUCTION METHOD FOR OCT IMAGES BASED ON EMPIRICAL MODE DECOMPOSITION

2013 ◽  
Vol 06 (02) ◽  
pp. 1350009 ◽  
Author(s):  
OLEG O. MYAKININ ◽  
DMITRY V. KORNILIN ◽  
IVAN A. BRATCHENKO ◽  
VALERIY P. ZAKHAROV ◽  
ALEXANDER G. KHRAMOV
Keyword(s):  
Noise Reduction ◽  
Empirical Mode Decomposition ◽  
Noise Suppression ◽  
Reduction Method ◽  
Tissue Structure ◽  
Diagnostic Process ◽  
Important Process ◽  
Post Processing ◽  
Mode Decomposition ◽  
Mesh Implant

In this paper, the new method for OCT images denoizing based on empirical mode decomposition (EMD) is proposed. The noise reduction is a very important process for following operations to analyze and recognition of tissue structure. Our method does not require any additional operations and hardware modifications. The basics of proposed method is described. Quality improvement of noise suppression on example of edge-detection procedure using the classical Canny's algorithm without any additional pre- and post-processing operations is demonstrated. Improvement of raw-segmentation in the automatic diagnostic process between a tissue and a mesh implant is shown.

A Fast Adaptive Salt and Pepper Noise Reduction Method in Images

2013 ◽  
Vol 32 (4) ◽  
pp. 1839-1857 ◽  
Author(s):  
Mehdi Nasri ◽  
Saeid Saryazdi ◽  
Hossein Nezamabadi-pour
Keyword(s):  
Noise Reduction ◽  
Reduction Method ◽  
Salt And Pepper Noise ◽  
Salt And Pepper
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