【作者】 赵辉；

【导师】 阮立明；

【作者基本信息】 哈尔滨工业大学 ， 工程热物理， 2008， 硕士

【摘要】 随着目标探测、光学成像、燃烧诊断等技术的开发和应用,对定向和定位的空间分辨率的要求更加严格,同时在红外辐射传输方面也遇到了大量的高温、多维、非均匀、各向异性散射等科学问题,对热辐射特性和传输的分析计算提出了更高的要求。考虑到实际中的定向辐射探测问题,本文的目的是提出一种简单快捷并且具有普适性的计算模型。有限体积法空间方向离散灵活,微元立体角、微元控制体内辐射能量守恒,物理意义明确,因而使得数值模拟结果具有很高的计算精度。本文在有限体积法现有离散坐标和离散空间基础上,提出广义多流法,该法能计算任意方向的辐射强度,结果与反向蒙特卡洛法结果吻合较好,能兼顾计算精度和计算效率。本文研究内容包括:1.介绍几种求解方向辐射的典型求解方法,分析比较各种方法的优点和缺点。2.在有限体积法基础上,建立广义多流法数学模型,编制相应的程序,针对参与性介质的物理模型,比较分析了广义多流法、反向蒙特卡洛法与源项六流法的计算结果,验证了广义多流法的可行性和精度。3.将整个尾喷焰计算区域包覆在某圆柱之内,在流场数据已知的前提下,用逐线积分法和粒子Mie散射理论计算喷焰中各控制体的吸收和散射系数,并将其与广义多流法整合为一个程序,模拟尾喷焰不同高度任意方向的截面总光谱出射辐射强度,分析其随高度和波数的变化规律。更多还原

【Abstract】 Over the last few decades, the problem of detecting directional radiative intensity signals has received considerable attention due to their numerous applications in the field of target detection, optical tomography, combustion diagnosis, temperature measurement of flame, and atmosphere remote sensing etc. Meanwhile, there appears to be a number of high temperature, multidimensional, nonhomogeneous, anisotropic scattering radiation problems in the field of infrared radiation transfer, which offers more require for the computation of radiation characteristics and transfer. Considering detecting problem at certain direction in engineering problems, a simple and efficient numerical model is presented in the present paper, which is suitable for solving directional radiative problems in the engineering applications.For having the advantages such as freedom of selection of control angle, guarantee of conservation of radiant energy, the results of Finite Volume Method(FVM) is very accurate. In the present paper, based on original discrete ordinate and direction of FVM, a multi-flux method (MFM) has been proposed to solve the radiation intensity in arbitrary direction with high accuracy and low time-consuming, which agree well with that of BMC. This dissertation includes the following contents:1. Based on FVM, a generalized Multi-Flux Method (MFM) model is presented. A 3-D validation model in participating media is solved by MFM, Backward MC (BMC), Sourced Six-Flux Method (SSF) respectively,and the result shows MFM is feasible and suitable to the practical engineering applications with high accuracy and low time-consuming.2. The entire exhaust plume as the computing domain was placed in a cylinder. The flow field having been known, with the help of Mie Scattering theory and the line-by-line (LBL) integration algorithms, MFM was used to simulated spectral radiation intensity with arbitrary direction of exhaust plume with different height. Finally, variable rule is analyzed between the result, height and wavenumber.更多还原