淡水和盐水中模拟气泡幕前向光散射特性

Forward scattering of laser by simulated bubble film in fresh and saline water

用理论计算和实验测量方法研究了模拟淡水和盐水中的气泡幕前向光散射特性。首先根据Mie散射理论,利用MATLAB编程计算了淡水和盐水中3种不同尺度分布的气泡群相散射函数,分析盐水相对淡水气泡群前向散射变化比例。然后根据实验测量数据,通过计算分析有无气泡幕光照度变化和散射光相对比例,提出差值分析可以探测液体中气泡。理论计算结果表明,对同一尺度分布的气泡群,盐水中气泡前向散射光比淡水中气泡散射光有所增加,最大达到14%,增幅随着散射角增加而减小。无气泡幕时测量盐水前向光散射比淡水光散射有所增加;有气泡幕时,在实验选择的不同压强条件下,同一种液体中,气泡幕前向平均相对散射增加约10%,然而压强相同时,盐水中气泡幕前向光散射平均照度比淡水增加约5%。

With theoretical calculation and experimental measurement methods, the forward light scattering properties of bubble film simulated in fresh and saline water are investigated. Based on Mie scattering theory, phase function of three different scale distributions bubble group in fresh and saline water were calculated using MATLAB, as well as relative percentage of forward scattering of laser by bubbles in saline water is analyzed compared with bubbles in fresh water. And based on the experimental measurements, the Difference-value Method which can be used for detecting bubble film in liquid through calculating the change in illumination and the relative percentage of light scattering with and without bubble film is proposed. Theoretical calculation result shows that forward light scattering by the same scale distribution bubble group in saline water increases up to 14 percent and decreases with the increasing scattering angle compared with fresh water. Forward light scattering in saline water without bubble increases somewhat than fresh water, the mean relative forward scat- tering（MRFS） increases by about 10 percent for the same liquid with the pressure increasing. However,MRFS increases by about 5 percent compared with fresh water at the same pressure.