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Modeling of Coupled Radiative and Convective Heat Transfer through Three-Dimensional Packed Beds with Random Arrangement

通过随机排列的三维填充床耦合辐射和对流传热的建模

基本信息

批准号：
62550140
负责人：
KUDO Kazuhiko
金额：
$ 1.28万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62550140/
关键词：
Radiative Heat Transfer Packed Bed Randomness Transmittance Monte Carlo Method 数値解析充墳層散乱

项目摘要

Radiative energy transmittance is studied through three-dimensional packed spheres with random arrangement by using a Monte Carlo method. The sphere diameter is far greater than the wave length of the radiative energy. The following results are obtained.1. A computer program is developed to produce three-dimensional randomly-arranged packed spheres with arbitrary packing density.2. Analytical and experimental studies through two-dimensional packed columns show that the main mechanisms of the radiative transmittance through the packed spheres are a collimation effect and a streaming effect of radiative energy passing through the spheres and the multiple reflection on the surfaces of the spheres.3. Analytical studies through three-dimensional packed spheres show that:(1) the radiative energy transmittance through regularly arranged packed spheres is generally lower than the one through randomly arranged packed spheres;(2) radiative energy transmittance obtained by a conventional continuous model approximation is far greater than the actual value especially for the packed spheres with higher packing density;(3) the regularity of the arrangement has little effect on the radiative energy transmittance through packed spheres, when the packing density is less than 0.3;(4) the radiative energy reflectance of the packed spheres is not affected by the packing density for random arrangement. For regular arrangement, it is increased by the increase in the packing density;(5) when the packed spheres have side walls, the radiative energy transmittance is increased due to the existence of the lower local packing density layer near the walls;(6) the radiative energy transmittance through the packed spheres with specular surfaces is higher than the one with diffuse surfaces.

用蒙特卡罗方法研究了随机排列的三维填充球的辐射能量透过率。球体直径远远大于辐射能量的波长。得到了以下结果：本文编制了一个计算机程序，可生成具有任意填充密度的三维随机排列的填充球体。通过二维填充柱的分析和实验研究表明，辐射透过填充球的主要机制是辐射能量通过球体的准直效应和流效应以及球体表面的多次反射。通过三维填充球的分析研究表明：(1)规则排列的填充球的辐射能量透过率普遍低于随机排列的填充球；(2)常规连续模型近似得到的辐射能量透过率远大于实际值，特别是对于填充密度较大的填充球；(3)当填充密度小于0.3时，排列的规律性对填充球的辐射能量透过率影响不大；(4)随机排列时，填充球的辐射能量反射率不受填充密度的影响。对于规则排列，它随着填料密度的增加而增加；(5)当填充球有侧壁时，由于在侧壁附近存在较低的局部填充密度层，使得辐射能量透过率增加；(6)具有镜面的填充球的辐射能量透过率高于具有漫射表面的填充球。