本文選題：寬篩分 + 冷模實(shí)驗(yàn)　； 參考：《青島科技大學(xué)》2015年碩士論文

【摘要】：流態(tài)化多晶硅化學(xué)氣相沉積(CVD)在連續(xù)操作時(shí)會(huì)形成比較寬的粒徑分布,需研究寬篩分顆粒體系的強(qiáng)化特性；加熱板內(nèi)構(gòu)件的加載同樣會(huì)影響流化床內(nèi)顆粒的流態(tài)化過(guò)程,需研究該內(nèi)構(gòu)件對(duì)寬篩分顆粒流化特性的強(qiáng)化作用,詳細(xì)內(nèi)容如下：(1)根據(jù)寬篩分顆粒流化特性,本文自制一套直徑0.215 m、高1.5m的帶有下椎體的流化床冷模實(shí)驗(yàn)裝置,Set 1-3為窄篩分實(shí)驗(yàn)物料、Set 4-5為寬篩分實(shí)驗(yàn)物料。通過(guò)分析床層段壓降研究軸向固含量分布規(guī)律,采用抽氣取樣法分析局部顆粒濃度分布,并通過(guò)篩分研究寬篩分顆粒粒徑分布,根據(jù)床層的靜止高度和流化高度研究床層平均空隙率的變化規(guī)律,通過(guò)采集流化床內(nèi)壓力脈動(dòng)信號(hào)并計(jì)算其功率譜密度、標(biāo)準(zhǔn)方差的研究方法分析床內(nèi)氣泡行為規(guī)律。(2)以窄篩分顆粒為對(duì)比,研究氣固流化床內(nèi)寬篩分實(shí)驗(yàn)物料的氣泡行為、軸向固含量分布、局部顆粒濃度分布、粒徑分布、床層空隙率。實(shí)驗(yàn)結(jié)果證明：(Ⅰ)在0.155m/s表觀氣速下,Set 2功率譜主頻值為3.667,Set 4為3.533,差別不大,Set 5與Set 1類似,均無(wú)明顯主頻,寬篩分實(shí)驗(yàn)物料中的細(xì)顆�？商岣邭馀莸木鄄ⅰ⑵扑轭l率,抑制大氣泡的產(chǎn)生；(Ⅱ)細(xì)顆粒的加入使寬篩分顆粒流化高度增加,軸向固含量分布更均勻,流化狀態(tài)更穩(wěn)定；(Ⅲ)局部顆粒密度隨軸向高度的增加而降低。密相區(qū)徑向方向上由中心線向邊壁處濃度逐漸增大,以Set4進(jìn)行分析,在0.155m/s表觀氣速下,軸向高度0.2m處的固相體積分?jǐn)?shù)由中心線處45%增大到邊壁處60%;(Ⅳ)以Set 4實(shí)驗(yàn)物料研究寬篩分顆粒粒徑分布。顆粒粒徑隨軸向高度的增加而降低,在0.294m/s表觀氣速下,底部顆粒平均粒徑為220gm,在1.0m處減小至115μm,界面處下降趨勢(shì)比較明顯,由0.2m處的210μm減小到0.4m處的165μm。在徑向方向上沒(méi)有明顯變化,在0.232m/s表觀氣速下,0.6m高度不同徑向位置的粒徑均在150μm左右；(V)細(xì)顆粒的加入可提高床層空隙率,在操作條件下,Set 4空隙率范圍為0.37～0.48,Set 5空隙率范圍為0.36～0.46,較Set 3的0.38～0.44有一定的提高。(3)在流化床中加入18塊加熱板內(nèi)構(gòu)件,對(duì)床內(nèi)顆粒流化特性產(chǎn)生積極的影響,本課題研究了加熱板內(nèi)構(gòu)件對(duì)寬篩分顆粒流態(tài)化過(guò)程的強(qiáng)化作用。實(shí)驗(yàn)結(jié)果證明,加熱板內(nèi)構(gòu)件使床層壓降產(chǎn)生小幅度的增加,增加值低于400Pa；空隙率減小趨勢(shì)不明顯；加載內(nèi)構(gòu)件后,Set4實(shí)驗(yàn)物料在0.155m/s表觀氣速下的主頻值由3.533增加到6.000,主頻幅值由2.795減小到2.504,0.232m/s表觀氣速下的主頻值由4.567增加到5.700,主頻幅值由6.553減小到4.264,床內(nèi)氣泡聚并、破碎頻率明顯升高,抑制大氣泡效果顯著。
[Abstract]:Fluidized polysilicon chemical vapor deposition (CVD) will form a wider particle size distribution during continuous operation, so the strengthening characteristics of wide sieve particle system should be studied, and the fluidization process of fluidized bed particles will also be affected by the loading of heating plate components. It is necessary to study the enhancement effect of the inner member on the fluidization characteristics of wide sieve particles. The detailed contents are as follows: (1) according to the fluidization characteristics of wide sieve particles, In this paper, a set of 0.215 m diameter and 1.5m high fluidized bed cold model test device with lower vertebra is made. Set 1-3 is a narrow screening material and set 4-5 is a wide screening material. The distribution of axial solid content was studied by analyzing the pressure drop of the bed section, the local particle concentration distribution was analyzed by the method of air sampling, and the particle size distribution of the wide sieve particle was studied by sieving. According to the static height and fluidization height of the fluidized bed, the variation of the average voidage of the bed is studied. The pressure pulsation signal in the fluidized bed is collected and its power spectral density is calculated. The study method of standard variance was used to analyze the behavior of bubbles in the bed. (2) the bubble behavior, axial solid content distribution, local particle concentration distribution and particle size distribution were studied in a gas-solid fluidized bed with narrow sieve particles as a comparison. Bed void ratio. The experimental results show that: (I) under the apparent gas velocity of 0.155m/s, the main frequency of power spectrum of Set 2 is 3.667% set 4 is 3.533, the difference is similar to that of set 1, and there is no obvious main frequency. The fine particles in the wide sieving experiment material can increase the coalescence and breaking frequency of bubbles. (II) the addition of fine particles increased the fluidization height of the wide sieve particles, the distribution of axial solid content was more uniform, and the fluidization state was more stable; (III) the local particle density decreased with the increase of axial height. In the dense phase region, the concentration increases gradually from the center line to the side wall in the radial direction. The concentration is analyzed with Set4, and at the apparent gas velocity of 0.155m/s, The solid volume fraction at the axial height of 0.2m increases from 45% at the center line to 60% at the side wall. (鈪，

本文編號(hào)：2051165