Acoustic-noise measurements on nominally identical small electrical machines

In Croatian Podravina relatively large quantities of natural gas was discovered. From various fields (Molve, Kalinovec, Stari Gradec) natural gas is pipelined to Gas Treatment Plant (GTP) Molve. Here, at GTP Molve III, technological procedures for purification of natural gas and its distribution are performed. With yearly natural gas production of 3,5 109 m3 GTP Molve III is major Croatian energy resource. Its safety and environment impact is matter of concern. Continuous acoustic emission leak monitoring system for Gas Treatment Plant (GTP) Molve as an improvement in technological and environment safety is considered. Application of a leak monitoring system under industrial conditions is a problem setting specific demands. In the paper attention is paid to some aspects of acoustic emission system implementation and the acoustic background noise definition problem. Acoustic noise measurements at a GTP Molve III were performed and some results considering background noise are presented. In the paper acoustic noise measurements performed at a GTP Molve III were presented. Across the GTP Molve III acoustical background have different spectral and amplitude characteristic. In the input area, measurements presented at a first group of measuring points included the impact of sand moved by gas fluid. Sand hits should be distinguished from acoustic emission caused by growing cracks. Motors noise and turbulence around valves are probably the main source of background noise on second group of measuring points. The conclusion is that background noise across the plant is highly different. Patterns found in one part of plant could not be applied on others measuring points. Background noise and its characterization are one of main problems solved before reliable operation of acoustic monitoring system could be applied. It is found that at GTP Molve III acoustic background is complicated, consisting of different sources at different part of a plant.

Download Full-text

An Efficient VLSI Architecture of Frequency Domain Kurtosis for Non-Stationary Acoustic Noise Measurements

2006 International Conference on Communications, Circuits and Systems ◽

10.1109/icccas.2006.285231 ◽

2006 ◽

Author(s):

Sheau-fang Lei ◽

Lih-yih Chiou ◽

Hsieh-wei Lee ◽

Bin-da Liu

Keyword(s):

Frequency Domain ◽

Acoustic Noise ◽

Vlsi Architecture ◽

Noise Measurements

Download Full-text

The Development of a Cross-Flow Fan for Electronic Devices Cooling with a Focus on Laptop Computers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.939.577 ◽

2014 ◽

Vol 939 ◽

pp. 577-583

Author(s):

Ai Tsung Li ◽

Ray Quen Hsu

Keyword(s):

Acoustic Noise ◽

Electronic Devices ◽

Cross Flow ◽

Optimal Number ◽

Ansys Fluent ◽

Laptop Computers ◽

Fan Performance ◽

2D Simulation ◽

Noise Measurements ◽

Cross Flow Fan

The directive is to develop a new type of cross-flow fan for cooling electronic devices. First, the module is based on the 60X60X6mm fan and attempts to use several parameters to enhance the fan’s performance. The parameters considered here include blade number, angle of the blade, impeller diameter, divergent structure, and outlet area. Both numerical and experimental analyses are carried out on the cross-flow fan which was oriented horizontally. The ANSYS Fluent software is used in a 2D simulation to predict the heat transfer coefficient and the flow fields. Next, the flow and acoustic noise measurements are carried out at different parameters with the aid of AMCA and semi-anechoic chambers. The results show that when the outlet vent size is 70% of fan outside diameter the outcome is an enhanced fan performance of 12%. The optimal number of blades is 37. A block is inserted below the fan blade to improve the fan performance by 8%. The numerical and experimental values of air flow were plotted and found to be consistent. In summary, this study provides a systematic process to develop a cross-flow fan that can meet the requirements for thin and light laptop computers.

Download Full-text