發(fā)布時(shí)間：2018-01-08 19:23

  本文關(guān)鍵詞：基于微通道表面帶有靜電的Monolith過濾器過濾性能的模擬研究　出處：《上海交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： monolith過濾器 通道 捕獲效率 單通道模型

【摘要】：高效空氣過濾器(HEPA)得到了廣泛的推廣和普及,是現(xiàn)代潔凈系統(tǒng)最主要的末級(jí)過濾器。HEPA是衡量一個(gè)國家過濾技術(shù)發(fā)展水平的重要標(biāo)準(zhǔn)。HEPA設(shè)備的高效節(jié)能和廉價(jià)是關(guān)鍵。因此,對(duì)低阻高效空氣過濾器進(jìn)行探索性實(shí)驗(yàn)研究是進(jìn)一步挖掘其市場(chǎng)潛力的一個(gè)突破點(diǎn)。monolith過濾器是由篩網(wǎng)狀介質(zhì)加工而成,具有形態(tài)整齊的多孔結(jié)構(gòu),流動(dòng)阻力很小。對(duì)于粒徑等于或大于孔徑的粒子具有絕對(duì)過濾能力。而對(duì)于能夠穿過微孔的亞微米粒子,monolith通道也能表現(xiàn)出很高的過濾能力,使得monolith過濾器成為新型高效空氣過濾器發(fā)展的一個(gè)重要方向。同時(shí),隨著微納米級(jí)加工技術(shù)的發(fā)展,目前核孔膜技術(shù)可以生產(chǎn)出孔徑達(dá)0.015~10μm的微孔薄膜濾料,使得基于微米級(jí)通道的monolith過濾器的研究逐漸被重視。然而,目前國內(nèi)外對(duì)于monolith過濾器的理論研究還比較少,通道的過濾機(jī)制還不完善,這為monolith過濾器的設(shè)計(jì)和制造增加了許多麻煩。針對(duì)這一情況,本文對(duì)monolith過濾器通道的過濾性能作了全面的研究并與傳統(tǒng)的纖維過濾器作比較,為設(shè)計(jì)和制造更加高效經(jīng)濟(jì)的空氣過濾器提供理論依據(jù)。本文采用單通道理論模型分析了表面帶有靜電的monolith過濾器通道的的過濾性能。首先研究了單個(gè)粒子在monolith微通道內(nèi)的運(yùn)動(dòng)特點(diǎn),結(jié)果表明,粒子直徑Dp0.1μm時(shí)主要受到布朗力和靜電力的作用,隨著Dp的增大,粒子的運(yùn)動(dòng)逐漸由流動(dòng)阻力主導(dǎo)。接著,本文還研究了氣流入口速度和方向,靜電力,粒子直徑等因素對(duì)monolith通道過濾效率的影響,結(jié)果表明,當(dāng)Dp0.1μm時(shí),入口速度u0增大,捕獲效率下降很快,u03m/s時(shí),捕獲效率接近于0且不再受氣溶膠入口速度的影響,粒子的捕獲效率隨氣溶膠入射角度的增大幾乎沒有變化,而當(dāng)Dp1μm時(shí),隨著u0的增大,通道的捕獲效率先減小后增大,粒子的捕獲效率隨氣溶膠入射角度的增大增加十分明顯。靜電力對(duì)monolith通道捕獲效率的影響十分顯著,研究表明,當(dāng)粒子直徑較小(Dp0.1μm)時(shí),粒子帶有與通道異種電荷時(shí)通道的捕獲效率顯著增強(qiáng)。因此采用人工的方法使monolith過濾器表面帶有穩(wěn)定高密度電荷具有重要意義,目前常用的方法是過濾器制造時(shí)在通道表面嵌入駐極體。粒子的直徑是通道捕獲效率最為重要的一個(gè)影響因素,隨著粒子直徑的增大,粒子的運(yùn)動(dòng)由主要受到布朗力和靜電力的作用逐漸轉(zhuǎn)變成由流動(dòng)阻力主導(dǎo)。粒子直徑Dp在0.01μm~1μm內(nèi),通道的捕獲效率隨著粒子直徑的增大先減小后增大,存在一個(gè)效率最低值,此時(shí)的粒子直徑稱為最大穿透力直徑Dpmax=0.1~0.4μm。本文還對(duì)monolith過濾器內(nèi)粒子沉積位置沿通道的分布規(guī)律作了分析,結(jié)果表明,大部分的粒子沉積在通道前10%區(qū)域,在其他位置沉積較少且分布較均勻,在工程應(yīng)用中,對(duì)于monolith過濾器的清洗應(yīng)該集中在通道前10%的位置。Dp=0.05μm時(shí),粒子沿通道沉積位置分布與氣流入口速度方向關(guān)系不大,而當(dāng)氣流入射速度增大時(shí),粒子沿通道沉積位置分布明顯向后移動(dòng);Dp=0.5μm時(shí),氣流進(jìn)入通道的速度增大和一定角度進(jìn)入通道均能使粒子的沉積位置向后推移。最后,本文在各方面條件相當(dāng)?shù)那闆r下比較了monolith過濾器與傳統(tǒng)纖維過濾器的過濾性能,結(jié)果表明,在保證氣流入口流速相等的情況下,monolith過濾器在對(duì)小粒子(Dp0.1μm)具有明顯更高的效率;u0=0.1m/s時(shí),纖維過濾器的過濾阻力ΔP=160Pa,monolith過濾器的過濾阻力ΔP=60Pa,約為纖維過濾器的1/3,這再一次證實(shí)了monolith過濾器相比于傳統(tǒng)纖維過濾器在處理亞微米級(jí)粒子具有高效率低能耗的優(yōu)良特性。
[Abstract]:High efficiency air filter (HEPA) has been widely popularized, is the final filter for the main.HEPA system is an important modern clean energy efficient standard.HEPA equipment to measure a country's level of development of filtering technology and cheap is the key. Therefore, exploratory experimental study is to further tap its potential market a breakthrough. The.Monolith filter is composed of a screen mesh is processed on medium low resistance and high efficiency air filters, with porous structure neat, flow resistance is small. With the absolute filtration ability for particle size is equal to or greater than the diameter of particles. The submicron particles can pass through the pore, the monolith channel can exhibit very high filtration capacity the filter makes monolith become an important direction of new high efficiency air filter development. At the same time, along with the development of micro nano machining technology, the core of Kong Mo The technology can produce microporous membrane pore size was 0.015~10 m, which makes the research of monolith filter based on the micro channel is gradually. However, at home and abroad for the theoretical research of monolith filter is still relatively small, channel filtering mechanism is not perfect, it adds a lot of trouble for the design and fabrication of monolith filter. In view of this situation, the filtering performance of monolith filter channel is studied and compared with the traditional fiber filter, so as to provide theoretical basis for air filter design and manufacture more efficient economy. This paper uses the theoretical model of single channel filter performance monolith filter channel with the electrostatic surface analysis. Movement characteristics first of all, the research of single particle in monolith in the micro channel. The results show that the main force of the particle diameter of Dp0.1 by Brown m and static electricity The role, along with the increase of Dp, the movement of the particles gradually by the flow resistance of LED. Then, this paper also studies the entrance flow velocity and direction of static electricity, influence factors, particle diameter on the monolith channel filter efficiency. The results showed that when Dp0.1 m, entrance velocity of U0 increases, the capture efficiency drops quickly, u03m/s when the impact of capture efficiency is close to 0 and no longer by sol entrance velocity, particle capture efficiency increases with the increase of aerosol incident angle is almost no change, while Dp1 m, with the increase of U0, the channel capture efficiency decreases first and then increases, the particle capture efficiency of aerosol with increasing incident angle increases obviously the influence of static electricity on monolith channel. The trapping efficiency is very significant, research shows that when the particle size is smaller (Dp0.1 m), and the effect of particle with the capture rate of channel charges when channel is significantly enhanced. Therefore. The use of artificial methods to make monolith filter surface has important significance with stable high charge density, the current commonly used method is to filter manufacturing in the channel is embedded on the surface of the electret. The diameter of the particles is the channel capture efficiency of one of the most important factors, with the increase of particle diameter, particle movement by the main force by Brown the static electricity and gradually transformed into the flow resistance. The particle diameter is dominated by Dp in 0.01 m~1 m, the channel capture efficiency increases with the particle diameter decreases first and then increases, there is an efficiency minimum value, the particle diameter is called the maximum penetration diameter of Dpmax=0.1~0.4 M. the position of particle deposition the monolith filter along the channel distribution are analyzed, the results show that the particle deposition in most of the channel before the 10% area, in other locations in the deposition less and more uniform distribution in the industry The application process for cleaning, monolith filter should be focused on the channel position in the top 10%.Dp=0.05 m, the relationship between particle distribution and deposition position along the channel entrance airflow velocity direction is small, and when the incident flow velocity increasing, the particle deposition distribution along the channel was moving to the rear; Dp=0.5 m, the airflow into the channel increase the speed and angle into the channel can make the particle deposition position goes backwards. Finally, this paper compares the performance of monolith filter, filter and traditional fiber filter in all aspects under the same conditions. The results show that the flow velocity is equal to the entrance in that case, the small particle filter in monolith (Dp0.1 m) with much higher efficiency.; u0=0.1m/s, the filtration resistance of delta P=160Pa fiber filter, filtration resistance Delta P=60Pa monolith filter, fiber filter is about 1/3, which once again It is proved that the monolith filter has the excellent characteristics of high efficiency and low energy consumption compared with the traditional fiber filter in the processing of submicron particles.

【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU834.83

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