【作者】 韦伟；

【导师】 翁春生；

【作者基本信息】 南京理工大学 ， 武器系统与运用工程， 2005， 硕士

【摘要】 由于通常情况下视气体介质为透明,所以气体辐射常常被忽略不计。然而在高温燃烧环境下,气体辐射在总的热量传递中占有不可忽略的比重。本文的目的是研究窄谱带模型在气体辐射中的应用。 本文包含以下几个内容: (1) 分析了气体辐射的特性,包括辐射与组成气体的原子或分子的能级跃迁、振动—转动谱线和谱线展宽之间的关系,以及光学厚度和普朗克函数对于气体辐射计算的意义和计算方法。分析了辐射—对流比这一物理量的含义,并据此物理量此判定是否要进行辐射量的计算。 (2) 分析气体辐射常用的三种模型:灰体模型、窄谱带模型和宽谱带模型的适用性,以及这三种模型的常规使用方法。 (3) 运用窄谱带模型,根据气体介质的物理性质,分别计算对应各个波长段的辐射强度和穿透率,进而计算总的辐射量。当气体介质等温、均匀时,分别计算气体介质的普朗克平均吸收系数、有效吸收系数和壁面入射平均吸收系数。 (4) 概述了本论文所编写程序的输入、输出参数的物理量、单位,以及输入、输出文件的格式。将输出数据绘制成曲线图,说明本文的研究细化到气体辐射过程中的每一个波长段。绘制温度值和烟灰微粒的体积分数改变后的曲线图,并与改变之前的相对应的曲线图进行比较,说明本文研究的实用性。将两种特殊情况下的输出结果与Hottel值和Ludwig值进行比较,计算结果与实验数据相符合,说明本文的模型及其应用是可靠的。更多还原

【Abstract】 Generally, we account the gas medium transparent, so gas radiation is always ignored. However, under high temperature combustion conditions, gas radiation is very important in the total heat transfer. The purpose of this dissertation is to study the application of narrow band model on gas radiation.The main points in the dissertation are as follows:(1) The dissertation Analyses the properties of gas radiation, and the computation of optical depth and Planck function. The dissertation analyses the agency of the rate of radiation convection in heat transfer as well.(2) The dissertation analyses the applicability of three models of gas radiation computation: the gray model, the narrow band model and the wide band model, and analyses the normal method of using them.(3) The dissertation calculating the spectral intensity and transmittance along the wavelength, using narrow band model, according to the physical property, as well as the total directional radiated energy flux. While the gas medium is isothermal uniformed, the dissertation calculates the effective absorption coefficient, the Planck-mean absorption coefficient and the wall-incident mean coefficient.(4) The dissertation outlines the volume, unit and style of input and output parameter in the program, and plots curves according to the output parameter, illustrates the fine of the study. The dissertation also plots curves after changing the temperature or the volume fraction of soot, and compares to the one before changed. And the dissertation compares the outcome to the data of Hottel and Ludwig.更多还原