扫描声强测量声功率技术的实验研究

An Experiment Study of the Sound Power Measurement Technology by the Scanning Sound Intensity Method

在半消声室用实验的方法研究了不同的扫描路径、不同的扫描线密度、不同的扫描速度与扫描声强测量声功率误差之间的关系;在半消声室添加背景噪声和在普通房间测量时不同的扫描路径与扫描测量声功率误差之间的关系。实验结果表明：无论是直线加半圆形、方形还是锯齿形扫描路径,均能收敛于声强真值,但锯齿形扫描路径测量精度最高,不确定度也较小。ISO9614-2推荐的手动扫描速度在0.1-0.5 m/s范围内,从满足工程测量精度角度看,扫描速度可在更宽的范围内选择。当扫描速度一定时,扫描线密度越大,扫描测量声功率误差越小。

Through experiment in a hemi- anechoic chamber, the relationships between different scanning path, different scanning linear density, different scanning speed and scanning measuring sound power error are studied. And the relationship between different scanning paths and scanning measuring sound power error in hemi-anechoic chamber added background noise and in common room is also studied. The experiment shows： whatever the scanning path is, such as straight line and half circle, rectangular, and saw-tooth-shape, the result can converge to the true value of sound intensity, but the saw-tooth-shape scanning path has the highest precision and its uncertainty degree is also low. The manual scanning speed is recommended at the range of 0.1 -0.5 m/s in ISO9614 - 2 standard, from the point of view of satisfying engineen＇ng measurement precision, the scanning speed can be chosen from a wider range. For a definite scanning speed, the more the scanning linear density is, the less the scanning measuring sound power error is.