稀释系统论文：分流稀释颗粒测量系统的模拟研究.doc

稀释系统论文：分流稀释颗粒测量系统的模拟研究【中文摘要】柴油机排气颗粒粒径极小，易被直接吸入体内，引发 呼吸道及肺部疾病，并且其常吸附有致癌物质，危害人类健康研究柴 油机颗粒排放特性及其控制技术的前提之一是耍有良好精度的颗粒 排放测量系统本文基于流体动力学原理，对现有…分流稀释颗粒测 量系统进行了研究应用FLUENT软件对分流稀释颗粒测量系统的稀 释混合能力进行了模拟计算分析了不同实验条件时,柴油机排气与 稀释空气在稀释通道内的混合状况O空气与柴油机排气由不同的入口 进入稀释通道，本文应用组分输运模型来研究其混合状况，并利用能 量方程、湍流模型考虑能量的转换与湍流的影响应用FLUENT软件 对分流稀释颗粒测量系统对传输管内流场的分布特征以及变化规律 进行了研究模拟分析了不同入口速度、入口温度下排气传输管内近 壁温度梯度场和整个管径范围内湍动能场的分布特征及变化规律文 中分别利用能量方程、湍流模型考虑能量的转换和湍流的影响模拟 分析了传输管内颗粒沉降率的影响因素及其变化规律结合传输管内 流场的分布特征以及变化规律，应用能量方程、湍流模型、辐射模型、 离散相模型分析了不同入口温度、入口速度下,颗粒在壁面上沉降率 的变化规律,得出了该传输管内颗粒沉降情况。

在考虑颗粒在排气传 输管壁面的沉降状况时，充分考虑了湍流脉动的影响,并对不同入口 参数下颗粒的热泳沉降率、湍流脉动沉降率以及热泳力与湍流脉动共 同作用下的总沉降率进行了分析比较文中应用离散坐标辐射模型来 考虑气体与颗粒间的辐射换热，应用离散相模型分析颗粒在壁面的沉 降率通过以上工作,得到了本文研究参数范围内该系统的稀释混合能 力和排气传输管内颗粒沉降率的情况，研究成果可为进一步优化该分 流稀释颗粒测量系统提供一定的理论依据和研究基础英文摘耍】Diesel exhaust particles are easi ly inhaled due to their fine size, which will cause respiratory and lung disease, and the particles have careinogenic substances adsorption, which is harmful to people" s health・ Particle pollution has become a problem needed to be solved urgently. First, we must have a better system for particulate emissions measurement to research of diesel particulate emission control technology. Tn this paper, many works have been done on the partial f1ow dilution sampling system for diesel particulate measurement based on the principles of computation&l fluid dynamics.The mixed~abi1ity of the partial flow dilution sampling system is studied by FLUENT software・ Diesel exhaust and air mixing quality are analyzed under different experimental conditions・ Due to air and diesel exhaust enter the dilution channel by different entry, Species Model was used to analyze their mixing quality, and Energy Equation was used to analyze their energy exchange, Turbulent Model was used to analyze turbulent effects.Distribution characteristics and variation regularity in the pipeline is studied by FLUENT software・ The di stribution characteristics and variation regularity of both temperature gradient field of near~wall and turbulent kinetic energy field of pipeline are analyzed under different conditions of inlet velocity and temperature based on Energy Equation, Viscous ModeL Influence factors and its variation regularity of diesel particulates deposition rate in the transport pipe are studied・ Combine the distribution characteristics and variation regularity of flow field in the transpoft pipe, particulates thermophoresis deposition, turbulent deposition and the total deposition under thermophoretic force and turbulenee are researched, under different conditions of inlet velocity and temperature using Energy Equation, Viscous Model and Radiation Model, Discrete Phase Mode 1. During the course of researching on particulates deposition, influence of turbulent edd is also taken into account enough, al so・ particulates thermophoresi s deposition, turbulent deposition and the total deposition are compared・ Radiation Model was used to analyze radiation heat transfer between ai r and parti culates in this paper .After the research work above, the mixed-ability of the particulate measurement system with partial f1ow dilution sampling system and diesel particulates deposition rate in the pipeline are concluded.Theoreti cal basi s and research foundation of further optimizing this system are supplied by the research results.【关键词】稀释系统混合能力柴油机颗粒热泳沉降湍流脉动 沉降【英文关键词】dilution sampling systemmixed~abi1ity diesel particulatesthermophoresis deposition turbulent deposition【目录】分流稀释颗粒测量系统的模拟研究摘要11-12 ABSTRACT 12-13 第 1 章绪论 14-22 1. 1课题研究背景14-17 1・2课题研究意义17 1.3国内外研究现状17-21 1. 3. 1多相流研究现状17-18 1. 3. 2热泳沉降研究现状18-21 1.4课题研究的主要内容21-22 第2章计算流体动力学基础22-32 2. 1引言22 2.2流体动力学基本控制方程22-27 2. 2. 1连续性方程22-23 2. 2. 2动量方程23-24 2. 2. 3能量守恒方程24-25 2. 2.4组分质量守恒方程25-26 2. 2. 5控制方程通用形式26-27 2. 3数值模拟方法27-30 2. 3. 1连续相数值模拟方法27-29 2. 3. 2离散相数值模拟方法29-30 2.4 FLUENT 软件 30-31 2.5 本章小结31- 32 第3章 模型的建立与方穆的离散求解32- 46 3.1引言32 3・2几何模型的建立与网格的划分方法32-33 3. 3常用边界条件33 3.4物理模型的选择33- 43 3.4. 1能量方程33-34 3. 4. 2辐射模型34- 35 3. 4. 3湍流模型及近壁区处理35-40 3. 4.4组分模型40-41 3. 4.5两相流模型41-43 3. 5求解器的选择及方程的离散与求解43-45 3. 5.1求解器的选择43 3. 5. 2方程的离散与求解43-45 3. 6本章小结45- 46 第4章 分流稀释颗粒测量系统稀释混合能力分析46- 58 4. 1引言46 4.2计算前处理46-52 4. 2. 1几何模型建立与网格划分46-49 4. 2. 2物理模型和边界条件的选定49-50 4. 2.3模拟用实验条件50-52 4.3不同实验条件下稀释通道内流场分析52-56 4. 3. 1稀释通道内不同横截而流场分布52-55 4. 3. 2采样前排气与稀释空气混合质量分析55-56 4.4模拟结果验证56-57 4. 5本章小结57- 58 第5章 基于颗粒沉降排气传输管数值模拟分析58- 78 5. 1引言58-59 5.2计算前处理59- 63 5. 2. 1几何模型的建立与网格划分59-61 5. 2. 2物理模型和边界条件的选定61-63 5. 3传输管流场分析63-71 5. 3. 1温度梯度场分布分析63-67 5. 3.2湍动能场分布分析67-71 5. 4柴油机排气颗粒在传输管内沉降特性模拟分析71-75 5.4.1不同入口温度下颗粒沉降率71-73 5. 4. 2不同入口速度下颗粒沉降率73-75 5.5本章小结75-78 全文总结与展望78-82 参考文献82-88 致谢88-89 学位论文评阅及答辩情况表89【◎采买全文◎】139938848 1381 13721同时提供论文写作一对一和论文发表服务•保过包发. 【说明】本文仅为中国学术文献总库台作提供，无涉版权。

作者如有异议请与总库或学校联弄。