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1、上海交通大学硕士学位论文 基于微通道表面带有静电的 Monolith过滤 器过滤性能的模拟研究 硕 士 研 究 生： 李 洪 根 学 号： 1120209335 导 师： 吴国江副教授 串 请 学 位： 工学硕士 学 科： 热能工程 所 在 单 位： 机械与动力工程学院 答 辩 日 期： 授予学位单 位： 上海交通大学 万方数据 Dissertation Submitted to Shanghai Jiao Tong University for the Degree of Master The simulation for the capture capability of electros
2、tatically charged monolith filter based on microchannels Candidate： Student ID： Supervisor： Academic Degree Applied for： Specialty： Affiliation： Date of Defence： Degree-Conferring-lnstitution： Li Honggen 1120209335 Prof. Wu Guojiang Master of Engineering Thermal Energy Engineering School of Mechanic
3、al and Power Engineering Shanghai Jiao Tong University 万方数据 丨 -1海交地大学硕士论文 基于微通道表面带有静电的 Mono I ith过滤器过滤性能的模 拟研究 摘要 高效空气过滤器 （ HEPA)得到了广泛的推广和普及，是现代洁 净系统最主要的末级过滤器。 HEPA是衡量 _“ 个岡家过滤技术发展水 平的重要标准。 HRPA设备的卨效节能和廉价是关键。因此，对低阻 高效空气过滤器进行探索性实验研究是进一步挖掘其市场潜力的一 个突破点。 nionolith过滤器是由筛网状介质加工而成，具有形态整齐的多孔 结构，流动阻力很小。对于粒径等
4、于或人于孔径的粒子具有绝对过滤 能力。而对于能够穿过微孔的亚微米粒子， monolith迎道也能表现出 很高的过滤能力， 使得 monolith过滤器成为新型高效空气过滤器发展 的一个重要方向。同时，随着微纳米级加工技术的发展，目前核孔膜 技术可以化产出 ?L径达 0.015 10 ura的微孔薄膜滤料 ,使得基于微米 级通道的 monolith过滤器的研究逐渐被重视。然而，目前国内外对于 monol池过滤器的理论研宄还比较少，通道的过滤机制还不完善，这 为 monolith过滤器的设计和制造增加了许多麻烦。针对这一情况，本 文对 monolith过滤器通道的过滤性能作 7全面的研宄并与传统的
5、纤 维过滤器作比较，为设计和制造更加高效经济的空气过滤器提供理论 依据。 万方数据 本文采用单通道理论校型分析了表面带有静电的 mono丨池过滤器 通道的的过滤性能。 ft先研宄了单个粒子在 m nol池微通道内的运动 特点，结果表明，粒子直径 Dp3m/s时，捕获效率接近于 0且不再受气溶胶入 U速度的影响，粒子的捕获效率随气溶胶入射角 度的增人几乎没有变化，而 _M1Dplum时，随着 u 的增大，通道的 捕获效率先减小后增大，粒子的捕获效率随气溶胶入射角度的增大增 加十分明显。静电力对 monolith通道抓获效率的影响十分显著，研究 表明，粒子直径较小 （ Dp 3m/ s, the
6、capture efficiency is close to 0 and will not longer be influenced by the aerosol inlet velocity; the particle capture efficiency hardly increases with the incident aerosol angle. And when Dp ljim, with the increase of uO, the capture efficiency of passage decreases and then increases;the particl万方数
7、据 摘要 capture efficiency increases obviously with the increase of the incident angle of aerosols. Electrostatic effect on the monolith channel capture efficiency is very significant. Studies show that when the particle diameter is small (Dp 0.1 fim), particles with the heterogeneous charge of passage
8、 with capture efficiency of the channel significantly enhanced. Therefore, the use of artificial means to make monolith filter surface with a stable of high-density charge is important, the most commonly used method is to embed the channel surface electret filter manufacturer. Therefore, the use of
9、artificial means to make monolith filter surface charged with a stable of high-density charge is important. The most commonly used method is to embed the channel surface electret filter. Diameter of the particle is a most important factor for capture efficiency of the channel. With the increase of p
10、article diameter, particle motion mainly dominating by action of Brownian forces and electrostatic forces gradually transfonns into dominating by the flow resistance, when Dp is in 0.01 pm 1 jim,the capture efficiency decreases with the particle diameter increase and then increases.There is a minimu
11、m value of efficiency,which called the largest particle penetmtioii diameter Dpmax = 0.1 0.4pm Particles deposited position distribution along the monolith filter channel is also analyzed in this paper. Results show that most of the particles deposited on previous 10% area of the channel,depositing
12、less 万方数据 上海交通大学硕士论文 and more evenly distributing in the other location.In engineering applications, monolith filter cleaning should be focused on previous 10% of the position of the channels. When Dp = 0.05fim, the particle distribution and the deposit location along the channel has little relation
13、ship with inlet airflow velocity direction, while the particle deposit location along the channel significantly moves backward with the gas flow velocity increases; When Dp=0.5jim, the speed increases and angled of the airflow into the channel both make the deposition position of the particle backwa
14、rds. Finally, we compare the filtration performance of monolith filter with fiber filters under comparable conditions in all respects. The results show that ensuring the flow inlet velocity conditions, monolith filter has a significantly higher efficiency for small particles (Dp 0. lira); uO = 0.1m
15、/ s, the fiber filter filtration resistance AP = 160Pa, while monolith filter filtration resistance AP = 50Pa, less than 1/3 of the fiber filters, which once again confirmed that the monolith filter have a low-power high efficiency characteristics in the processing of submicron particles compared to
16、 conventional fiber filter. Key words： monolith filters,channel,capture effience,single channel model VII 万方数据 摘要 目录 第一章绪论 . 1 1.1前言 . 1 1.2空气过滤技术的发展 . 3 1.3高效空气过滤器的现状 . 5 1.4课题的主要内容及意义 . 7 第二章空气洁净原理 . 9 2.1空气过滤对象 -大气尘 . 10 2.1.1大气尘组成 . 10 2.1.2大气尘浓度 . 10 2.1.3大气尘危害 . 11 2.2过滤分离 . 13 2.3对微粒的过滤机理 . 1
17、4 2.4空气过滤器的性能表示 . 14 2.4.1过滤效率 . 15 2.4.2穿透率 . 15 2.4.3 阻力 . 15 2.4.4过滤速度 . 16 2.5 Monolith过滤器的关键技术 -微孔滤膜 . 16 2.5.1微孔滤膜的性能 . 16 2.5.2微孔滤膜的应用 . 17 2.5.3核孔膜的制备 . 18 2.6 monolith过滤器通道过滤性能影响因素的理论分析 . 19 第三章粒子运动的理论分析和模拟方法 . 20 3.1 monolith过滤器内粒子的运动方程 . 20 3.1.1布朗力 . 21 3.1.2流动阻力 . 21 3.1.3静电力 . 22 VIII 万方数据