scholarly journals COGENERATION UNIT NOISE REDUCTION BY ITS CASE

2021 ◽  
Vol 2021 (2) ◽  
pp. 4501-4504
Author(s):  
RADEK STRAMBERSKY ◽  
◽  
VACLAV PAVELKA ◽  
TOMAS PAWLENKA ◽  
PAVEL SURANEK ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Frequency Spectrum ◽  
Noise Source ◽  
Microphone Array ◽  
Noise Measurement ◽  
Sound Power ◽  
Final Number ◽  
Beamforming Algorithm

This paper deals with cogeneration unit noise measurement by the acoustic camera. Noise is not only measured as the final number of sound power levels, but also its original location is determined with the use of the beamforming algorithm. The properties of the used microphone array are considered and numerically calculated as every different microphone array layout will measure with another resolution. From the frequency spectrum, the possible technical source is determined. The results of noise source visualization show the cogeneration unit case noise decreasing effect while also offering the possibilities for design improvements.

scholarly journals Aeroacoustic noise reduction by application of end plates on wall-mounted finite airfoils

2021 ◽  
Vol 62 (5) ◽  
Author(s):  
Erik Schneehagen ◽  
Thomas F. Geyer ◽  
Ennes Sarradj ◽  
Danielle J. Moreau
Keyword(s):  
Noise Reduction ◽  
Microphone Array ◽  
Boundary Layer Transition ◽  
Tip Vortex ◽  
Layer Transition ◽  
Aeroacoustic Noise ◽  
End Plate ◽  
Array Measurements ◽  
Field Noise ◽  
Naca 0012

Abstract One known method to reduce vortex shedding from the tip of a blade is the use of end plates or winglets. Although the aerodynamic impact of such end plates has been investigated in the past, no studies exist on the effect of such end plates on the far-field noise. The aeroacoustic noise reduction of three different end-plate geometries is experimentally investigated. The end plates are applied to the free end of a wall-mounted symmetric NACA 0012 airfoil and a cambered NACA 4412 airfoil with an aspect ratio of 2 and natural boundary layer transition. Microphone array measurements are taken in the aeroacoustic open-jet wind tunnel at BTU Cottbus-Senftenberg for chord-based Reynolds numbers between 75,000 and 225,000 and angles of attack from 0$$^\circ$$ ∘ to 30$$^\circ$$ ∘ . The obtained acoustic spectra show a broad frequency hump for the airfoil base configurations at higher angles of attack that is attributed to tip noise. Hot-wire measurements taken for one configuration show that the application of an end plate diffuses the vorticity at the tip. The aeroacoustic noise contribution of the tip can be reduced when the endplates are applied. This reduction is most effective for higher angles of attack, when the tip vortex is the dominant sound source. Graphic abstract

Sound Power Assessment, Noise Source Identification and Directivity Analysis of Compaction Machines

2021 ◽  
Author(s):  
Milind Dadarao Kandalkar ◽  
Jaykumar bari ◽  
Dhondiram Mole ◽  
Nagesh Harishchandra Walke
Keyword(s):  
Source Identification ◽  
Noise Source ◽  
Sound Power ◽  
Noise Source Identification

scholarly journals Rotating equipment fault noise location based on adaptive beamforming algorithm

2021 ◽  
Vol 2113 (1) ◽  
pp. 012042
Author(s):  
Yongshao Xu ◽  
Bingzheng Liu ◽  
Haotian Shang ◽  
Mingduo Wang
Keyword(s):  
Microphone Array ◽  
State Parameter ◽  
Noise Signal ◽  
Source Location ◽  
Adaptive Beamforming ◽  
Rotating Machinery ◽  
Acoustic Sensor ◽  
Unsteady State ◽  
Beamforming Algorithm ◽  
Fault Source

Abstract Rotating machinery often produces continuous impact during operation due to the change of load and speed, which shows the characteristics of unsteady state and time-varying. Its working state can not be comprehensively judged by a single vibration state parameter. Therefore, this paper proposes to use acoustic sensors to collect the fault noise signal of rotating machinery, and use the whole column of sensors to detect the fault noise signal. Based on the microphone array, this paper studies the adaptive beamforming algorithm (MVDR) to locate the fault source of rotating machinery in space. The effect of fault source location is verified by simulation and equipment measurement experiments. The acoustic sensor does not in contact with the equipment, which will not damage the generator set, but also provide more effective information for fault source location and fault diagnosis and analysis.

Wavepacket noise source model for microphone array data analysis of hot supersonic jets

2013 ◽  
Vol 134 (5) ◽  
pp. 4127-4127 ◽  
Author(s):  
Philip Morris ◽  
Robert Dougherty ◽  
Chris Nelson ◽  
Alan Cain ◽  
Kenneth Brentner
Keyword(s):  
Data Analysis ◽  
Noise Source ◽  
Microphone Array ◽  
Source Model ◽  
Supersonic Jets ◽  
Array Data
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