Three-Dimensional Radiative Heat Transfer Including Polarization

随着激光器的发展， 单色辐射偏振光束相互作用 与散射材料已经获得了相当大的重要性 在传热领域。 激光现在被用作 用于探测热燃烧气体的诊断工具以及 大气，并测量包装的辐射特性- 床、隔热材料、陶瓷和人体组织。 激光- 基于微加工系统的微电子技术 工业和拥有巨大的潜力，在制造 微机械结构 的医疗应用 激光的范围从治疗心脏病和癌症， 牙科和眼科 使用激光束作为 “镊子”抓住和操纵活细胞的小块， 被认为是改进基因定位方法的一种方法。 这些应用程序中的大多数必须归类为 由于激光束的有限尺寸 它是线性极化的，它们通常涉及多个 和各向异性散射。 确实需要发展 辐射传输的理论模型， 纳入所有这些因素，并制定指导方针， 处理偏振效应的近似程序。 本项目是一个理论和实验研究的三个- 三维辐射传热，包括极化和 多重散射 具体来说，多重影响 在已知偏振（线性， 圆形或椭圆形）正在研究中。 激光 光束垂直入射到 圆柱形散射介质 散射中心是 随机分布的均匀球形颗粒 在介质中。 正在开发一个理论模型 基于三维矢量输运方程， Stokes参数 通常的散射相函数 将由4x 4相位矩阵代替。 运输 方程将被简化为一维形式， 双重傅里叶变换方法，以及由此产生的方程 都可以用安巴楚米安的方法解决 反向散射 然后，将使用双逆计算辐射 傅立叶变换 首先进行理论分析 对于小的球形颗粒，即，瑞利 散射 一系列精心控制的实验将 用悬浮在纯水中的乳胶微球进行 来验证理论模型。 的浓度 微球的光学厚度将变化， 散射介质的范围将从薄到厚。 的 这项研究的结果将提供深入了解一些 实际问题涉及的相互作用极化 具有散射介质的激光束。 的发展 更现实的辐射模型应该有一个显着的 在使用激光的许多领域中， 转让、制造和医药。

With the development of the laser the problem of the interaction of a polarized beam of monochromatic radiation with a scattering material has gained considerable importance in the heat transfer community. Lasers are now used as diagnostic tools to probe hot combustion gases as well as the atmosphere, and to measure the radiative properties of packed- beds, thermal insulations, ceramics, and human tissue. Laser- based micromachining systems abound in the microelectronics industry and hold great potential in the fabrication of micromechanical structures. The medical applications of lasers range from treating heart disease and cancer to dentistry and eye surgery. The use of laser beams as "tweezers" to seize and manipulate bits of living cells is being considered as a way to improve gene-mapping methods. Most of these applications must be classified as multidimensional because of the finite size of the laser beam which is linearly polarized, and they often involve multiple and anisotropic scattering. A definite need exists to develop a theoretical model for radiative transfer that can incorporate all these factors and to develop guidelines and approximate procedures for handling polarization effects. This project is a theoretical and experimental study of three- dimensional radiative heat transfer including polarization and multiple scattering. Specifically, the effects of multiple scattering on a laser beam of known polarization (linear, circular, or elliptical) are under investigation. The laser beam is incident perpendicular to the top, flat surface of a cylindrical scattering medium. The scattering centers are homogeneous spherical particles which are randomly distributed within the medium. A theoretical model is being developed based on the three-dimensional vector transport equation for the Stokes parameters. The usual scattering phase function will be replaced by a 4x4 phase matrix. The transport equation will be reduced to a one-dimensional form using the double Fourier transform method, and the resulting equation will be solved by Ambartsumian's method. The back-scattered radiation will then be calculated using a double inverse Fourier transform. The theoretical analysis will be first carried out for small spherical particles, i.e., Rayleigh scattering. A series of carefully controlled experiments will be conducted with latex microspheres suspended in pure water to validate the theoretical model. The concentration of the microspheres will be varied so that the optical thickness of the scattering medium will range from thin to thick. The results of this research will provide insight into a number of practical problems involving the interaction of a polarized laser beam with a scattering medium. The development of a more realistic radiation model should have a significant impact in many fields where lasers are utilized including heat transfer, manufacturing, and medicine.