Investigation of Centrifugal Blower Noise

1999 ◽  
Author(s):  
Christopher L. Banks ◽  
Sean F. Wu
Keyword(s):  
Radiation Pattern ◽  
Free Field ◽  
Sound Radiation ◽  
Noise Generation ◽  
Centrifugal Blower ◽  
Noise Radiation ◽  
Passenger Vehicles ◽  
Generation Mechanisms ◽  
Semi Empirical ◽  
Noise Spectra

Abstract This paper presents the results of an ongoing investigation of noise radiation from centrifugal blowers used in passenger vehicles. The semi-empirical formulation previously derived by the authors (1998) for predicting noise spectra of centrifugal blowers running in a free field is extended to centrifugal blowers installed in a HVAC scroll housing. Because of the presence of the scroll and cutoff, the flow fields are different from those in a free field. Accordingly, the noise generation mechanisms become much more difficult to analyze and model. The previous model assumed a monopole type sound radiation pattern, and predicted the broadband component of the noise spectra well. This model is extended to include the contributions of both monopole and directional dipole sound radiation. It is this complex radiation that is characteristic of a centrifugal blower situated inside a scroll housing with a cutoff. Comparisons of the calculated and measured noise spectra were demonstrated, and good agreements were obtained in all cases.

Sound radiation from a centrifugal blower in a free field.

1996 ◽  
Vol 99 (4) ◽  
pp. 2509-2529
Author(s):  
Shigong Su ◽  
Sean F. Wu ◽  
Morris Y. Hsi
Keyword(s):  
Free Field ◽  
Sound Radiation ◽  
Centrifugal Blower

scholarly journals A phenomenological approach to jet noise: the two-source model

2019 ◽  
Vol 377 (2159) ◽  
pp. 20190078 ◽  
Author(s):  
Christopher K. W. Tam
Keyword(s):  
Jet Noise ◽  
Phenomenological Approach ◽  
Source Model ◽  
Large Set ◽  
Noise Generation ◽  
Theme Issue ◽  
Generation Mechanisms ◽  
Similarity Jet ◽  
Spectrum Data ◽  
Noise Spectra

This is a review of the two-source model of jet noise. The model was developed phenomenologically a number of years ago. One of the principal results associated with this model was the identification of two similarity jet noise spectra. This was accomplished through extensive comparisons with a large set of NASA spectrum data. It was found that these two noise spectra when combined appropriately would fit measured noise spectra of jets in any direction regardless of jet temperature and Mach number. Other experimental data in support of the two-source model have since been found. They are discussed in this paper. One of the purposes of this paper is to elaborate on the flow physics of turbulence, noise generation mechanisms and directivity that are the underpinnings of the model. More recent works show the similarity spectra are applicable, well beyond their original database, to noise of military jets, rockets and even volcanoes. This article is part of the theme issue ‘Frontiers of aeroacoustics research: theory, computation and experiment’.

Transonic Axial Compressors Loss Correlations: Part I — Analysis and Update of Loss Models

2020 ◽  
Author(s):  
Marco Manfredi ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressor ◽  
Reduced Order ◽  
Axial Compressors ◽  
Analysis And Design ◽  
Main Driver ◽  
Validity Range ◽  
Loss Models ◽  
Generation Mechanisms ◽  
Semi Empirical ◽  
System Designs

Abstract The quest for greener, more efficient aircraft engines is the main driver for the development of innovative compression system designs. Reduced order design tools rely nevertheless on semi-empirical loss models, whose validity range is often not net or in general not verified. The present work aims at defining a set of loss correlations, which could readily be employed in the analysis and design process of modern transonic axial compressors. In part I, the main entropy generation mechanisms are described together with a review of the most commonly employed modelling approaches. Selected loss models are then deeper investigated and updated to increase both their range of validity and the accuracy of their predictions. In Part II, the effectiveness of the investigated models will be tested for one specific low aspect ratio axial compressor stage.

MODELLING OF THE NOISE SPECTRA OF AXIAL FLOW FANS IN A FREE FIELD

1997 ◽  
Vol 200 (4) ◽  
pp. 379-399 ◽  
Author(s):  
S.F. Wu ◽  
S.G. Su ◽  
H.S. Shah
Keyword(s):  
Free Field ◽  
Axial Flow ◽  
Noise Spectra

Free-field sound radiation measurement with multiple synchronous cameras

Measurement ◽  
2021 ◽  
pp. 110605
Author(s):  
Paolo Gardonio ◽  
Roberto Rinaldo ◽  
Loris Dal Bo ◽  
Roberto Del Sal ◽  
Emanuele Turco ◽  
...  
Keyword(s):  
Free Field ◽  
Sound Radiation ◽  
Radiation Measurement ◽  
Field Sound

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.

Piezoelectric Array Sensing for Real-Time, Broad-Band Sound Radiation Measurement

1999 ◽  
Vol 121 (4) ◽  
pp. 446-452 ◽  
Author(s):  
A. Preumont ◽  
A. Franc¸ois ◽  
S. Dubru
Keyword(s):  
Numerical Study ◽  
Broad Band ◽  
Sound Radiation ◽  
Radiation Measurement ◽  
Mean Square ◽  
Noise Radiation ◽  
Radiation Sensor ◽  
Reconstructed Volume ◽  
The Mean ◽  
Array Sensing

This paper proposes a noise radiation sensor consisting of an array of independent piezoelectric patches connected to an adaptive linear combiner. The coefficients of the linear combiner are adapted in such a way that the mean-square error between the reconstructed volume displacement (or velocity) and either numerical or experimental data is minimized. A numerical study is conducted, to analyze the influence of the size of the piezoelectric array on the reconstructed volume velocity.

Classical Electrodynamics and Acoustics: Sound Radiation by Moving Multipoles

1997 ◽  
Vol 119 (2) ◽  
pp. 271-282 ◽  
Author(s):  
G. C. Gaunaurd ◽  
T. J. Eisler
Keyword(s):  
Dirac Equation ◽  
Free Field ◽  
Sound Radiation ◽  
Equation Of Motion ◽  
Rotating Machinery ◽  
Classical Electrodynamics ◽  
Radiation Patterns ◽  
Frequency Distributions ◽  
Acoustic Sources ◽  
Power Radiation

In classical electrodynamics (CED) P. Dirac used the average of retarded and advanced fields to represent the bound field and their difference to represent the free field in his derivation of the (Lorentz-Dirac) equation of motion for an electron. The latter skew-symmetric combination filtered out the radiation part of the field. It can also be used to derive many properties of the power radiated by acoustic sources, such as angular and frequency distributions. As in CED there is radiation due to source acceleration and radiation patterns exhibit the “headlight effect.” Power radiation patterns are obtained by this approach for point multipoles undergoing various motions. Applications to sound radiation problems from rotating machinery are shown. Numerous computed plots illustrate all cases.

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