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光干涉原理和Mie理论计算结果表明,单泡声致发光中气泡前向Mie散射的振荡信号,主要是由于气泡的透射光束和表面反射光束之间光干涉产生的. 这些干涉波峰形成了测量气泡半径的空间标尺,标尺的单位长度δR由散射角θ,检测光波波长和流体光折射率确定,而每个波峰就是标尺的刻线,它们与该时刻的气泡半径大小一一对应. 在30°—50°散射角范围内,利用前向Mie散射实验测定了单泡声致发光中气泡的最大半径,R(t)曲线及平衡半径,表明前向Mie散射是一种便捷的测定气泡运动特性的有效方法.
关键词:
单泡声致发光
前向Mie散射
光干涉 相似文献
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光干涉原理和Mie理论计算结果表明,单泡声致发光中气泡前向Mie散射的振荡信号,主要是由于气泡的透射光束和表面反射光束之间光干涉产生的.这些干涉波峰形成了测量气泡半径的空间标尺,标尺的单位长度δR由散射角θ,检测光波波长和流体光折射率确定,而每个波峰就是标尺的刻线,它们与该时刻的气泡半径大小一一对应.在30°-50°散射角范围内,利用前向Mie散射实验测定了单泡声致发光中气泡的最大半径,R(t)曲线及平衡半径,表明前向Mie散射是一种便捷的测定气泡运动特性的有效方法. 相似文献
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光在水中吸附膜层气泡上的散射特性 总被引:3,自引:1,他引:2
光在水中大尺度气泡上散射特性的研究多是基于Davis模型.该模型没有考虑到吸附膜层对光在气泡上散射的影响,而海水中的大多数气泡都有膜层附着,这些膜层会影响到气泡的光散射特性.本文从几何光学的角度出发,建立了吸附膜层气泡的体积散射函数简化公式.在此理论基础上,模拟计算了尺度远大于入射光波长的大气泡散射光强分布曲线,得出光照射下气泡上散射光强的远场特性,讨论了影响气泡散射光强分布的主要因素.并与无膜气泡光散射分布曲线比较,讨论了油膜膜厚、折射率等参量对气泡的光散射特性影响.得出结论:吸附膜层气泡的光强分布曲线与无膜气泡相似,但吸附膜层会削弱前向散射光,增强后向散射光. 相似文献
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从Mie散射理论出发,利用单气泡散射理论模型研究了激光前向散射特性以及激光前向散射光轴周围激光照度分布状态。选用波长为632.8 nm的激光,在不同介质和不同压强下测量并分析了气泡幕的散射光照度。研究表明,激光前向散射光主要分布在离光轴0.588的范围内,其沿激光光轴呈轴对称分布,并且沿光轴方向截面分布为高斯分布;在考虑水体自身散射时,0.006 MPa、0.008 MPa和0.010 MPa下,各个散射角被散射掉的光大概占激光前向散射照度的35%、45%和55%,可得到无论考虑水体自身散射与否,激光前向散射光与压强皆成反比。 相似文献
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《中国光学与应用光学文摘》2005,(2)
P733.32 2005021589 舰船尾流中脏气泡光的散射特性=Analysis of light ex- tinction characteristic of ship wake[刊,中]/张毓芬(大连 测试技术研究所.辽宁,大连(116013)),田稷…//光电子 技术与信息.-2004,17(4).-34—37 阐述了舰船尾流气泡的分布特性和气泡数密度的衰 减特性。基于Mie散射理论,计算和分析了干净气泡和脏 气泡光的背向散射特性,群体干净气泡和脏气泡光的背向 散射特性。图5参5(严寒) 相似文献
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舰船远程尾流的散射光能量分布特性 总被引:4,自引:0,他引:4
为探索光尾流的探测和自导模式,研究了舰船远程尾流中气泡群的散射光能量分布特性.根据米氏理论推导了舰船尾流气泡群的光散射能量分布函数的计算公式,基于此公式对干净的尾流气泡群和覆盖着两种典型有机膜的脏尾流气泡群的能量分布函数进行了数值计算,得到了它们的能量分布特性.计算和分析结果表明,气泡群的前向光散射能量远大于后向散射,前向散射能量占总散射能量的90%以上;散射能量分布函数在小于1°的前向小角度散射角范围内迅速增加到40%以上,然后随散射角的增加缓慢增加;气泡表面附着的有机膜会较显著的增强气泡群的后向散射能量.但由于后向散射能量占总散射能量的比例很小,有机膜对前向散射能量的减小幅度不大. 相似文献
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A novel bubble detection technique based on light intensity and Mie scattering theory for spinning solution is presented theoretically and experimentally. With the light intensity in every direction, the particle or bubble size distribution can be calculated with the Mie scattering theory. The light intensity distribution in every direction, corresponding to the light intensity received by every assumed annulus of the detector has been calculated theoretically. According to the light intensity distribution, the size distribution of bubbles can be deduced. A series of standardized polystyrene micro-sphere (with 7 μm diameter) solution has been used not only as sample for experiments and calibration, but also as the bubbles in the glycerin. Theoretical and experimental results show that the technique can be used for bubble detection, in order to improve the traditional bubble detection scheme, and to lower production costs. 相似文献
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Mie scattering efficiency of a large spherical particle embedded in an absorbing medium 总被引:1,自引:0,他引:1
I. Wayan Sudiarta Petr Chylek 《Journal of Quantitative Spectroscopy & Radiative Transfer》2001,70(4-6):709-714
The Mie scattering calculations are usually performed for non-absorbing spherical particles embedded in a non-absorbing medium. We consider a case of an absorbing sphere placed in an absorbing medium. We find, by numerical calculation for large size parameter of the order of 104, that the scattering efficiency of a spherical particle in an absorbing medium approaches the reflectance of a plane surface at perpendicular incidence. 相似文献
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本文应用Eikonal近似将微椭球用其等效的球来近似, 结合Mie理论对吸收介质中微椭球体颗粒光学参数进行了数值计算。 结果表明, 椭球位置变化时, 散射和吸收性能发生变化。离心率增大时, 散射和吸收系数都增大, 离心率越大增大的越明显。波长增大时, 在紫光波长为0.4 μm和近红外区波长为1.58 μm处散射系数出现了峰值, 而吸收系数单调增大。相对折射率实部以及虚部变化对光学参数均有影响, 颗粒的吸收性越强, 散射相应地减弱。结果表明这种数值解析方法能有效地计算椭球体颗粒的光学参数。 相似文献
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A. Collin D. Lacroix G. Jeandel 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,92(1):85-110
Radiative transfer through water spray curtains has been presently addressed in conditions similar to devices used in fire protection systems. The radiation propagation from the heat source through the medium is simulated using a 2D Discrete Ordinates Method. The curtain is treated as an absorbing and anisotropically scattering medium, made of droplets injected in a mixing of air, water vapor and carbon dioxide. Such a participating medium requires a careful treatment of its spectral response in order to model the radiative transfer accurately. This particular problem is dealt with using a correlated-K method. Radiative properties for the droplets are calculated applying the Mie theory. Transmissivities under realistic conditions are then simulated after a validation thanks to comparisons with some experimental data available in the literature. Owing to promising results which are already observed in this case of uncoupled radiative problem, next step will be to combine the present study with a companion work dedicated to the careful treatment of the spray dynamics and of the induced heat transfer phenomena. 相似文献
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Huiling He Wei Li Xiaohui Zhang Min Xia Kecheng Yang 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(12):1467-1475
This paper proposes the spheroidal model for analyzing the light scattering characteristics of an air bubble. The angular distributions of light scattered by a large spheroidal bubble with end-on incidence are calculated using geometrical optics approximation. The divergence factor, diffraction, and phase shift are considered in the computation. The MATLAB code was developed and verified using the Mie result for a spherical bubble, and the scattering patterns of the two methods agreed well. The effects on the scattering properties are analyzed in terms of the size and shape parameter of the bubble and the incident beam width. The relations between the deviation angle and incident angle, emergent light intensity, and scattering angle are analyzed and used to explain the scattering patterns of a spheroidal bubble. 相似文献
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Based on Mie scattering theory and the theory of multiple light scattering, the light scattering properties of air bubbles in a wake are analysed by Monte Carlo simulation. The results show that backscattering is enhanced obviously due to the existence of bubbles, especially with the increase of bubble density, and that it is feasible to use the Monte Carlo method to study the properties of light scattering by air bubbles. 相似文献
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The model of the optical impulse scattering echo based on Mie theory and backscattering properties of bubble populations is presented. The experimental results of optical impulse scattering echo for a ship in the ocean is in agreement with the simulated experiment. The wake bubbles significantly influence the laser scattering echo process in the ocean. When the testing system is outside the wake, the distinct scattering echoes of interface between wake bubbles and water are received. When the testing system is inside the wake, the intensity of the echo attenuates with the increased scattering of wake bubbles. These phenomena of laser echoes in different periods are analyzed. 相似文献
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Lei Wu Hongru Yang Xudong Li Bin Yang Gaoping Li 《Journal of Quantitative Spectroscopy & Radiative Transfer》2007,108(1):54-64
The scattering patterns and optical properties of large spherical bubbles in water are calculated by both Geometrical-optics theory and Debye-series expansion of the Mie amplitudes. In the Geometrical-optics calculations, the wave-front spreading factor and phase information are all taken into consideration. A detailed comparison between the two methods is presented. It is found that scattering patterns calculated from the Geometrical-optics approach agree reasonably with those obtained by Debye series when the size parameter is larger than approximately 400. In the case of scattering properties, the Geometrical-optics method can produce reliable results with the Debye expansion for size parameters larger than approximately 50. The Geometrical-optics results without the phase interferences are also reliable, but it cannot display the oscillations and the ripple structure as a function of size parameter. 相似文献
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Geometrical optics approximation for light scattering by absorbing spherical particles 总被引:1,自引:0,他引:1
Haitao Yu Yuehuan Wei 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(13):1178-2428
By means of geometrical optics, an approximation method is presented to compute the light scattering intensity of absorbing spherical particles illuminated by a plane wave. For absorbing particles, the effective refractive index and the effective refractive angle are related to the complex refractive index and incident angle. The formulas for calculation of the break of phases of reflection and refraction, which are different from the case of transparent particles, are exactly derived. Verification of the geometrical optics approximation (GOA) was performed by case studies and comparison of the present results with the Mie scattering. It is found that agreement between the GOA and the Mie theory is excellent in forward directions for weakly/moderately absorbing particles. Differently, for strongly absorbing particles, good agreement between the calculation methods is in the forward directions and large scattering angles. The agreement between the GOA and the Mie theory is better for larger particles. 相似文献
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碳纳米粒子悬浮液具有良好的光限幅性质,是一种优良的宽波段光限幅材料。通过热传导方程和米氏散射理论建立了微气泡半径与入射光能量、碳纳米粒子悬浮液散射系数和透过率的理论模型。采用Matlab数值模拟了散射系数随微气泡尺寸因子的变化关系,碳纳米粒子悬浮液光限幅性能随入射光能量的变化规律。研究了气泡尺寸因子、入射激光能量以及波长对碳纳米粒子悬浮液光限幅特性的影响。研究发现当激光能量达到一定值时,微气泡的半径保持恒定,不再随入射激光能量的增加而增加。微气泡尺寸的增大对碳纳米粒子悬浮液的透过率有着显著的影响。同时,碳纳米粒子悬浮液对不同入射光波长和光能表现出不同的光限幅性能。研究结果为实验研究提供了理论指导。 相似文献