發(fā)布時間：2018-04-25 22:12

  本文選題：袋式除塵器 + 脈沖噴吹清灰�。� 參考：《蘭州交通大學(xué)》2015年碩士論文

【摘要】：在大氣污染十分嚴峻的背景下,各行業(yè)的排放標準越來越嚴格,而長袋脈沖袋式除塵器可以比較容易的適應(yīng)新標準,應(yīng)用越來越廣泛。在此過程中袋式除塵器越來越大型化,需要對其進一步的研究,特別是清灰系統(tǒng)和流場分布的研究,以提高設(shè)備的整體效率及壽命。目前很難對除塵器內(nèi)部復(fù)雜的氣固兩相流場進行測試,而CFD數(shù)值模擬方法可以得到噴吹清灰過程和除塵時內(nèi)部流動情況,可以為袋式除塵器的改進提供一些依據(jù)。清灰效果是影響除塵器能否正常工作的重要因素,中箱體內(nèi)的氣流分布對除塵器壽命的影響也很大。本文使用ICEM網(wǎng)格劃分軟件對噴吹區(qū)域和整個除塵器分別建立1:1的幾何模型,并劃分結(jié)構(gòu)化網(wǎng)格;利用計算流體力學(xué)方法分別對脈沖噴吹清灰過程中壓力分布和除塵時氣流分布情況進行模擬分析。通過脈沖噴吹過程模擬結(jié)果和實驗數(shù)據(jù)的對比,驗證了數(shù)值模擬過程的合理性,并對文丘里管、噴吹壓力和濾袋長度對濾袋壁面壓力分布的影響進行了模擬分析,得出:文丘里管對濾袋壁面峰值壓力影響較大,在相同的噴吹條件下使濾袋壁面最大峰值壓力由16.9kPa減小至15.7kPa,降低了7%,出現(xiàn)峰值的位置向后推移0.5m,濾袋中下游的峰值壓力由7.5kPa減小至5.4kPa,降低了28%;脈沖噴吹壓力對濾袋壁面各位置的峰值壓力影響都很大,在不設(shè)文丘里管的情況下,當(dāng)噴吹壓力為0.35MPa時,峰值壓力為18.5kPa,下游壓力為8kPa;當(dāng)噴吹壓力為0.2MPa時,峰值壓力為13.7kPa,下游壓力為3.8kPa;最大峰值壓力和下游峰值壓力分別降低了26%和53%;在相同的噴吹條件下,濾袋長度對距袋口1m范圍內(nèi)的壓力影響很小,對中下游的峰值壓力影響較大,當(dāng)濾袋長度由6m增加到9m時,下游峰值壓力由8kPa下降到2kPa。將YTALS-03-60型袋式除塵器濾袋加長至8m后進行數(shù)值模擬,結(jié)果表明流場分布不均勻,各列濾袋的流量分配系數(shù)相差很大,清灰前后A列、P列濾袋的流量分配系數(shù)分別為1.42、1.14和1.21、1.62,清灰前后的最大不均勻系數(shù)分別為0.61、0.75;靠近箱體壁面處的流速大于濾袋矩陣中心的速度,遠離進口區(qū)域的流速大于進口區(qū)域流速,進氣口的射流對濾袋底部形成直接噴吹。對原模型袋式除塵器進行增加擋風(fēng)板的改造后重新建模計算,得出擋風(fēng)板高度為1m、2m時氣流分布要好于原模型,清灰前后的最大不均勻系數(shù)分別為0.47、0.57和0.52、0.78;進氣口對濾袋底部的直接噴吹被消除,但在進風(fēng)口下側(cè)形成了渦流,不利于粉塵的沉降。改變擋風(fēng)板橫向尺寸,當(dāng)擋風(fēng)板高度為3m時,清灰前后的最大不均勻系數(shù)達到最小,為0.37、0.35,除清灰前A列濾袋、清灰后P列濾袋不滿足平衡要求外,其余濾袋都能滿足;改變灰斗與中箱體的連接位置后,進風(fēng)口下側(cè)的渦流被消除;擋風(fēng)板對除塵器內(nèi)部流場的影響很大,增加擋風(fēng)板后流場較原模型有很大改善。
[Abstract]:In the background of severe air pollution, the emission standards of various industries are becoming more and more strict, while the long-bag pulse bag filter can easily adapt to the new standards, and its application is becoming more and more extensive. In order to improve the overall efficiency and service life of the equipment, it is necessary to further study the bag dust collector, especially the ash removal system and the flow field distribution. At present, it is difficult to measure the complex gas-solid two-phase flow field in the dust collector, and the CFD numerical simulation method can get the internal flow in the process of soot cleaning and dust removal, which can provide some basis for the improvement of the bag dust collector. The ash removal effect is an important factor to influence the normal operation of the dust collector, and the airflow distribution in the middle box has a great influence on the life of the dust collector. In this paper, the 1:1 geometric model of the injection area and the whole dust collector is established by using the ICEM mesh division software, and the structured grid is divided. The pressure distribution and air flow distribution in the process of soot cleaning by pulse injection were simulated and analyzed by computational fluid dynamics (CFD) method. The rationality of numerical simulation is verified by comparing the simulation results of pulse injection process with experimental data. The effects of Venturi tube, injection pressure and filter bag length on the pressure distribution on the wall of the filter bag are simulated and analyzed. The results show that Venturi tube has great influence on the peak pressure of filter bag wall. Under the same injection conditions, the maximum peak pressure on the filter bag wall was reduced from 16.9kPa to 15.7 KPA, and the peak position of the filter bag decreased by 0.5 m, the peak pressure of the middle and lower reaches of the filter bag decreased from 7.5kPa to 5.4 KPA, and the peak pressure of the filter bag decreased by 28%. The peak pressure at every position of the bag wall has a great influence on it. When the injection pressure is 0.35MPa, the peak pressure is 18.5 KPA, the downstream pressure is 8 KPA, and the injection pressure is 0.2MPa. The peak pressure was 13.7 KPA, the downstream pressure was 3.8 KPA, the maximum peak pressure and downstream peak pressure were reduced by 26% and 53%, respectively. Under the same injection conditions, the filter bag length had little effect on the pressure within 1m distance from the pocket mouth, but had a great effect on the peak pressure in the middle and lower reaches. When the filter bag length increased from 6 m to 9 m, the downstream peak pressure decreased from 8kPa to 2 KPA. After the filter bag of YTALS-03-60 bag filter is extended to 8 m, the numerical simulation results show that the flow field is not uniform, and the flow distribution coefficient of each filter bag is very different. Before and after ash cleaning, the flow distribution coefficients of A column P filter bags were 1.42U 1.14 and 1.21g 1.62, respectively, and the maximum non-uniform coefficients before and after ash cleaning were 0.61m 0.75, respectively. The velocity near the wall of the box was greater than that at the center of the filter bag matrix. The velocity far away from the inlet area is larger than the inlet velocity, and the jet from the inlet directly injects the bottom of the filter bag. After the retrofitting of the original model bag dust collector with the addition of the windshield, it is obtained that the airflow distribution is better than that of the original model when the height of the windshield is 1 m ~ 2 m. The maximum inhomogeneity coefficient before and after cleaning is 0.47U 0.57 and 0.52U 0.78.The direct injection of air inlet to the bottom of the filter bag is eliminated, but vortex is formed at the lower side of the inlet, which is not conducive to dust deposition. When the height of the baffle is 3 m, the maximum non-uniform coefficient before and after cleaning reaches the minimum, which is 0.37 ~ 0.35. Except for the A-column filter bag before ash cleaning and the P row filter bag after ash cleaning, all the other filter bags can be satisfied. The vortex at the lower side of the inlet is eliminated by changing the connecting position of the ash bucket and the middle box, and the influence of the windshield on the internal flow field of the dust collector is great, and the flow field after the increase of the baffle is greatly improved than that of the original model.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X701.2

【參考文獻】

相關(guān)期刊論文 前1條

1 吳佳林;郝俊強;凡祖?zhèn)?;袋式除塵高溫過濾材料的研究概況[J];輕紡工業(yè)與技術(shù);2014年05期

，

本文編號：1803203