摘 要
本文較全面地檢索了國內(nèi)外有關(guān)靜電與旋風(fēng)除塵技術(shù)的文獻(xiàn)資料，測試研究了脈沖供電時直筒式離心脈沖靜電除塵器內(nèi)部的流場分布，得出了各種不同實(shí)驗(yàn)條件下三維流場分布規(guī)律及入口風(fēng)速和脈沖供電電壓對流場分布的影響，并就進(jìn)一步弄清離心脈沖靜電除塵器內(nèi)部整體流場的分布規(guī)律及其除塵機(jī)理和優(yōu)化結(jié)構(gòu)設(shè)計(jì)參數(shù)提出幾點(diǎn)建議。實(shí)驗(yàn)研究得到的主要結(jié)論如下：
〈1〉無供電情況下的離心脈沖靜電除塵器相當(dāng)于筒體中間帶有一根金屬線的普通旋風(fēng)除塵器。內(nèi)部氣流的切向速度和徑向速度沿筒體壁向方向大體上先增大后減小，軸向速度分布則無規(guī)律可循。且徑向速度隨著入口風(fēng)速的增大在中心渦核處開始出現(xiàn)小部分沿筒體壁向方向的徑向流。
〈2〉在脈沖電壓為45Kv的條件下，切向速度隨著入口風(fēng)速的增大而增大；軸向速度的整體變化比較平緩，并呈現(xiàn)出一定的規(guī)律性；徑向速度的分布曲線近似水平直線。
〈3〉在入口風(fēng)速為8.5 的條件下，脈沖電暈電壓越高，相應(yīng)的切向速度越小，軸向速度越大，徑向速度變化不明顯。隨著半徑的增大，切向速度基本上逐步變小，軸向速度先減小后又逐步增大，徑向速度的分布曲線則比較平穩(wěn)。
〈4〉與普通旋風(fēng)除塵器相比，離心脈沖靜電除塵器內(nèi)部流場的分布規(guī)律有所改善，更有利于除塵。這可能是因?yàn)殡姇灅O線和電風(fēng)的影響使得除塵器內(nèi)部流場的湍流度反而減小，要證實(shí)這一點(diǎn)還有待于進(jìn)一步通過實(shí)驗(yàn)深入研究。
關(guān)鍵詞 離心脈沖靜電除塵器；除塵機(jī)理；脈沖供電；流場測試；五孔球形探針

Experimented Study of the Flow Field Distribution inside CIESP
Abstract
In this paper, many literatures on electrostatic precipitation and cyclone technology were consulted in an all-round way, and the flow field distribution inside a straight-tube cyclone impulse electrostatic precipitator (CIESP) was measured on condition of impulse voltage. Finally, the law of the three-dimension flow field distribution and the effects of entry velocity and impulse voltage were found under different conditions. To further study the law of the whole flow field distribution and dust removal mechanism of CIESP and optimize parameters of the structure, some suggestions were also put forward here. Conclusions based on the tested results can be summarized as follows:
A CIESP is equivalent to an ordinary cyclone with a central discharge wire in the tube body at 0 Kv voltage. The tangential velocity and radial velocity inside air flow are reduced after increasing on the whole in the direction along the tube body wall, and the distribution of the axial velocity is in complete confusion. Besides, a small part of radial current along the tube body wall is found on the centre of the whirlpool as an increase in entry velocity .
On condition of impulse voltage 45 Kv, an increase in entry velocity is found to boost the tangential velocity, and the whole change of the axial velocity is more gentle and demonstrates certain regularity, and the distribution curve of the redial velocity is also found like to be horizontal line.
Under the circumstances that the entry velocity is 8.5m/s, the higher impulse corona voltage is, the smaller the corresponding tangential velocity is, and the larger the axial velocity is, but the change of the radial velocity is not obvious. With the increase of the radius, the tangential velocity is reduced progressively and basically, and the axial velocity increases progressively after reducing first, but the distribution curve of radial velocity becomes more steady.
Compared with ordinary cyclone, the law of the flow field distribution inside CIESP is improved to some extent, which benefits dust removal. This may be due to the effects made by corona wire and electric wind, which reduce the turbulance degree of the flow field inside CIESP. But investigations must be further carried through all kinds of experiments to verify this hypothesis.
Keywords: cyclone impulse electrostatic precipitator;
dust removal mechanism; impulse power supply;
flow field measurement; five-hole probe
目 錄
1 前言 5
1.1 研究背景 5
1.2 研究現(xiàn)狀 6
1.2.1 靜電旋風(fēng)除塵器除塵機(jī)理及除塵性能的研究現(xiàn)狀 6
1.2.2 靜電旋風(fēng)除塵器內(nèi)部流場分布的研究現(xiàn)狀 7
1.2.3 供電技術(shù)與流場測試技術(shù)簡述 8
1.3 研究意義和目的 9
1.4 主要工作內(nèi)容 9
2 實(shí)驗(yàn)設(shè)計(jì) 10
2.1 實(shí)驗(yàn)裝置 10
2.1.1 供風(fēng)裝置 10
2.1.2 供電裝置 10
2.1.3 測量儀器 11
2.2 實(shí)驗(yàn)方法 13
2.2.1 除塵器入口風(fēng)速的測定方法 13
2.2.2 除塵器內(nèi)部三維流場的測定方法 13
3 實(shí)驗(yàn)結(jié)果與討論 14
3.1 入口風(fēng)速對流場的影響 14
3.1.1 無供電時入口風(fēng)速對三維流場的影響 14
3.1.2 脈沖供電時入口風(fēng)速對三維流場的影響 16
3.2 脈沖電暈電壓對流場的影響 17
3.3 對比分析 19
3.4 實(shí)驗(yàn)誤差來源分析 19
3.5 結(jié)論與建議 20
致 謝 21
參考文獻(xiàn) 22
附 錄1 23
附 錄2 24