OPTIMIZATION OF LOW NOISE BIONIC FAN USING GRAY RELATIONAL ANALYSIS COUPLED WITH ENTROPY MEASUREMENT

2014 ◽  
Vol 13 (01) ◽  
pp. 1450005 ◽  
Author(s):  
SHUMING CHEN ◽  
YONGQI GUO ◽  
DENGFENG WANG ◽  
SHAOMING SUN
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Gray Relational Analysis ◽  
Acoustic Performance ◽  
Relational Analysis ◽  
Entropy Measurement

This research presents a hybrid optimization method for the determination of the optimal geometry parameters which can minimize the A-weighted sound pressure level of bionic fan on condition that the mass flow rate of the bionic fan is as high as possible. A hybrid approach of gray relational analysis (GRA), Taguchi method, and entropy measurement has been used to obtain better acoustic performances with three basic geometry parameters, which are blade number, boss ratio, and blade stagger angle. A L9(34) orthogonal array has been used for conducting the experiment for optimization of flow and acoustic performances. The problem of multiple performance indices is simplified into single performance index by using gray relational grade. The designed experimental results are utilized in GRA, and the weights of the flow and acoustic performances are determined by using the entropy measurement method. Meanwhile, the optimal combination of bionic fan parameters is determined by using GRA method. Moreover, the validation tests show that the overall sound pressure level (SPL) reduces by 15.50% at the cost of mass flow rate reducing by 3.00%. The comparison of the A-weighted SPL for acoustic tests between original fan and optimized bionic fan demonstrates that the acoustic performance obviously improve from 20 Hz to 6300 Hz. Therefore, it is clearly shown that the proposed approach in this paper can be an useful tool to improve acoustic performance of bionic fan.

scholarly journals Study of Heat Transfer and the Hydrodynamic Performance of Gas–Solid Heat Transfer in a Vertical Sinter Cooling Bed Using the CFD-Taguchi-Grey Relational Analysis Method

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2225
Author(s):  
Junpeng Fu ◽  
Jiuju Cai
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Grey Relational Analysis ◽  
Hydrodynamic Performance ◽  
Inlet Temperature ◽  
Air Mass ◽  
Relational Analysis ◽  
Grey Relational

The vertical sinter cooling bed (VSCB) is a high-efficiency energy-saving and environmentally friendly waste heat recovery equipment. In this study, a computational fluid dynamics (CFD) convection model was established to reveal the typical factors on the thermodynamic performance in VSCB. Indeed, a multiple performance optimal algorithm based on the Taguchi-grey relational analysis (GRA) method was first applied to investigate the effects of geometric and operational factors, including the diameter of the bed, height of the bed, air mass flow rate, air inlet temperature, and sinter mass flow rate, on improving the heat transfer (Ex) and hydrodynamic performance (Pdrop) and obtain the optimum combination of each factor in VSCB. The results found that the diameter of the bed was the most influential factor contributing the multiple types of performance with a contribution rate of 70.51%, followed by the air mass flow rate (15.84%), while the height of the bed (0.27%) exerted a limited effect on the performance of multiple processes. The optimal combination of factors (A1B5C5D5E1) was compared with the initially selected parameters by performing a confirmation test. The performances of heat transfer and hydrodynamics were improved by the Taguchi with the GRA method.

scholarly journals Experimental study of aerodynamic noise performance of improved air distributor for ships

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110012
Author(s):  
Yuejiao Guo ◽  
Guozeng Feng ◽  
Shuya Lei ◽  
Bo Meng ◽  
Yang Xu
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Static Pressure ◽  
Resistance Coefficient ◽  
Pressure Level ◽  
Channel Structure ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Reduction Effect

In ships, aerodynamic noise from the variable-air-volume fan is a common problem. This study experimentally explores the strategy of reshaping the traditional C-shaped channel structure to an L-shape to reduce noise. The noise level and resistance coefficient of the improved air distributor are analysed, and the results show that the noise of the original air distributor is 56.3 dB(A) under the rated working conditions (static pressure of 800 Pa and flow rate of 350 m3/h), which exceeds the International Maritime Organisation’s (IMO) ship noise limit (55 dB(A)). For the improved air distributor, the noise pressure level is 38.5 dB(A), the sound pressure level of high-frequency noise is reduced by 48% and the peak sound pressure level appears at 125 to 250 Hz, a frequency below the threshold of human hearing. Thus, the reshaping of the channel has a significant noise reduction effect. When the static pressure is 400 Pa and the flow rate is 100 to 500 m3/h, the sound pressure level of the improved air distributor is reduced by 29.9% to 32.2% to become less than 55 dB(A). Thus, the sound pressure level at the outlet of the improved air distributor meets the IMO ship noise standard.

scholarly journals An Experimental and Numerical Study on the Effect of Spacing between Two Helmholtz Resonators

Acoustics ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 97-117
Author(s):  
Abhishek Gautam ◽  
Alper Celik ◽  
Mahdi Azarpeyvand
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Field ◽  
Transmission Loss ◽  
Numerical Study ◽  
Pressure Level ◽  
Impedance Tube ◽  
Acoustic Performance ◽  
Helmholtz Resonators ◽  
Maximum Transmission

This study investigates the acoustic performance of a system of two Helmholtz resonators experimentally and numerically. The distance between the Helmholtz resonators was varied to assess its effect on the acoustic performance of the system quantitatively. Experiments were performed using an impedance tube with two instrumented Helmholtz resonators and several microphones along the impedance tube. The relation between the noise attenuation performance of the system and the distance between two resonators is presented in terms of the transmission loss, transmission coefficient, and change in the sound pressure level along the tube. The underlying mechanisms of the spacing effect are further elaborated by studying pressure and the particle velocity fields in the resonators obtained through finite element analysis. The results showed that there might exist an optimum resonators spacing for achieving maximum transmission loss. However, the maximum transmission loss is not accompanied by the broadest bandwidth of attenuation. The pressure field and the sound pressure level spectra of the pressure field inside the resonators showed that the maximum transmission loss is achieved when the resonators are spaced half wavelength of the associated resonance frequency wavelength and resonate in-phase. To achieve sound attenuation over a broad frequency bandwidth, a resonator spacing of a quarter of the wavelength is required, in which case the two resonators operate out-of-phase.

scholarly journals Assessment of an acoustic chamber for testing structure-borne sound transmission in a double-panel assembly

2021 ◽  
Author(s):  
Peter Bulski
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Performance Indicator ◽  
Sound Transmission ◽  
Pressure Level ◽  
Vibration Isolators ◽  
Acoustic Performance ◽  
Detailed Assessment ◽  
Vibratory Acceleration ◽  
Acoustic Chamber

An acoustic chamber was designed for testing structure-borne sound transmission in a double-panel assembly induced by point connectors. Several vibration isolators were tested and the overall effects on the noise transmitted through the assembly were predicted by establishing the link between the vibratory acceleration level (VAL) and the sound pressure level (SPL). A detailed assessment of the acoustic chamber showed that a major modification of the double-panel assembly is required before the acoustic performance of this assembly could be evaluated directly using insertion loss (IL) measurements where the sound pressure level (SPL) difference is the performance indicator. This thesis describes the assessment findings and retrofitting options. It is concluded that adjustments to the VAL-to-SPL relation are required to account for distance, radiation efficiency, and room effects. Further adjustments to the acoustic chamber are required to enhance its performance.

scholarly journals Collaborative improvement of efficiency and noise of bionic vane centrifugal pump based on multi-objective optimization

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Houlin Liu ◽  
Zhiming Cheng ◽  
Zhipeng Ge ◽  
liang dong ◽  
cui dai
Keyword(s):  
Response Surface ◽  
Centrifugal Pump ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Optimization Method ◽  
Pressure Level ◽  
Hydraulic Efficiency ◽  
Multi Objective Optimization ◽  
Acoustic Performance ◽  
Multi Objective

The hydraulic and acoustic performance of centrifugal pump is closely related to hydraulic structure parameters, and they are contradictory. In order to solve this contradiction, this paper introduces the pit bionic structure, and proposes an optimization method based on multi-objective test design and response surface to improve the hydraulic and acoustic performance. Taking the bionic vane pit diameter, axial spacing and radial spacing as design variables. Taking the maximum hydraulic efficiency and total sound pressure level reduction of centrifugal pump as the corresponding objectives. The multiple regression response surface model was constructed to determine the optimal parameter combination of hydraulic performance and noise collaborative optimization. The optimization results were verified by numerical simulation and experimental test. The results show that the response surface multi-objective optimization method has high prediction accuracy, has obvious synergistic effect on the hydraulic and acoustic performance. The highest point of the efficiency curve after optimization is shifted to the direction of large flow, which widens the high efficiency working area of centrifugal pump. Under the rated condition, the hydraulic efficiency is increased by 3.03%, the efficiency increase rate is 4.21%, the total sound pressure level is reduced by 4.96 dB, and the noise reduction rate is 3.01%.

scholarly journals Assessment of an acoustic chamber for testing structure-borne sound transmission in a double-panel assembly

2021 ◽  
Author(s):  
Peter Bulski
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Performance Indicator ◽  
Sound Transmission ◽  
Pressure Level ◽  
Vibration Isolators ◽  
Acoustic Performance ◽  
Detailed Assessment ◽  
Vibratory Acceleration ◽  
Acoustic Chamber

An acoustic chamber was designed for testing structure-borne sound transmission in a double-panel assembly induced by point connectors. Several vibration isolators were tested and the overall effects on the noise transmitted through the assembly were predicted by establishing the link between the vibratory acceleration level (VAL) and the sound pressure level (SPL). A detailed assessment of the acoustic chamber showed that a major modification of the double-panel assembly is required before the acoustic performance of this assembly could be evaluated directly using insertion loss (IL) measurements where the sound pressure level (SPL) difference is the performance indicator. This thesis describes the assessment findings and retrofitting options. It is concluded that adjustments to the VAL-to-SPL relation are required to account for distance, radiation efficiency, and room effects. Further adjustments to the acoustic chamber are required to enhance its performance.

Regulatory Mechanism of Voice Intensity Variation

1964 ◽  
Vol 7 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Nobuhiko Isshiki
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Intensity Variation ◽  
Pressure Level ◽  
Expiratory Muscle ◽  
Laryngeal Control ◽  
The Relationship ◽  
The Voice

The relationship between the voice intensity (sound pressure level), the subglottic pressure, the air flow rate, and the glottal resistance was investigated. Simultaneous recordings were made of the sound pressure level of voice, the subglottic pressure, the flow rate, and the volume of air utilized during phonation. The glottal resistance, the subglottic power, and the efficiency of voice were calculated from the data. It was found that on very low frequency phonation the flow rate remained almost unchanged or even slightly decreased with the increase in voice intensity while the glottal resistance showed a tendency to augment with increased voice intensity. In contrast to this, the flow rate on high frequency phonation was found to increase greatly, while the glottal resistance remained almost unchanged as the voice intensity increased. On the basis of the data it was concluded that at very low pitches, the glottal resistance is dominant in controlling intensity (laryngeal control), becoming less so as the pitch is raised, until at extremely high pitch the intensity is controlled almost entirely by the flow rate (expiratory muscle control).

Exploration on relationship between flow rate and sound pressure level of piezoelectric pump

2019 ◽  
Vol 26 (2) ◽  
pp. 609-616 ◽  
Author(s):  
Lipeng He ◽  
Xiaoqiang Wu ◽  
Da Zhao ◽  
Wei Li ◽  
Guangming Cheng ◽  
...  
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Piezoelectric Pump

Behavior of Jet From an Orifice in a Pipe Under Pulsating Flow

2007 ◽  
Author(s):  
Ema Tamura ◽  
Junjiro Iwamoto
Keyword(s):  
Unsteady Flow ◽  
Flow Rate ◽  
Sound Pressure Level ◽  
Measurement Errors ◽  
Sound Pressure ◽  
Pressure Level ◽  
Flow Meter ◽  
Orifice Flow ◽  
Accuracy Of Measurement ◽  
Orifice Flow Meter

An orifice flow meter is widely used in industry to measure the flow rate of gas or liquid in the pipe because of its simplicity. The accuracy of measurement is acceptable when the steady flow is measured. However, it is often the case in industry that the unsteady flow must be measured. It is not yet known, under unsteady flow conditions, how accurate the flow rate can be measured using the orifice flow meter and where the measurement errors come from. In the present paper to answer these questions a pulsating air flow is considered as the simplest of the various types of unsteady flow patterns and the measurement of the flow field in the pipe with orifice is made in detail. The sound pressure level is also measured by probe tube microphone. A comparison is made of power spectrum densities obtained by measurement of sound pressure level and by the velocity measurement from laser Doppler anemometer.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

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