利用后向散射光空间谱强度分布探测尾流气泡的实验研究

利用自行设计制作的尾流模拟系统产生气泡，应用散射光空间频谱测量分析系统，对水中气泡群的后向散射光空间谱强度分布进行测量和分析，研究了不同探测距离的散射光衰减对其强度分布的影响.结果表明，在气泡密度、大小分布不变的情况下，扩束光照明时，由于参与光散射的气泡数目增加对散射光在水中传播衰减的补偿，散射空间谱强度分布的峰值和半宽值均不随探测距离变化；而细光束照明时，散射谱强度分布峰值随探测距离的增加而减小，半宽值则逐渐增大.所以在远距离探测时，细光束的探测效果好.

Study of Air Bubbles in Water Based on Spatial Spectrum Intensity of Backward Scattered Light

The peak value and Full Width at Half Maximum(FWHM) of scattered light's spatial spectrum intensity distribution of air bubbles in water can be used to determine bubbles'size and density. By the developed air bubbles producing setup and scattered light's spatial spectrum intensity measuring and analyzing system,how detecting distance affects backward scattered light's spatial spectrum intensity was investigated experimentally. The experiment results show that as air bubbles'size and density are invariable,the change of detecting distance has different effect on the peak value and the FWHM of scattered light's spatial spectrum intensity distribution under different illuminations. The peak value and the FWHM of scattered light's spatial spectrum intensity distribution are unchanging as the detecting distance increases under expanded beam illumination,for the number of bubbles scattering light increases constantly,which can offset scattered light intensity's losing caused by a longer distance propagation. But the.peak value reduces gradually and FWHM increases as the detecting distance increases under the slim beam illumination. The experiment results also show at slim beam illumination has advantage for long distance detecting.