NUMERICAL SIMULATION ON SPRAY EVAPORATION PROCESS FOR SMALL-SCALE QUENCH TOWER IN LIMITED SPACE
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摘要: 针对受限空间内小型急冷塔冷却水蒸发过程,运用计算流体力学(CFD)进行数值模拟,基于涡壳进气型急冷塔研究了喷嘴雾化粒径、喷射速度、喷射角度等喷嘴运行参数对急冷塔内蒸发过程的影响机制。结果表明:随着液滴粒径的增大,液滴蒸发时间、轴向以及径向蒸发距离均随之显著上升,粒径由40 μm增大至80 μm时蒸发时间增加了293%;当液滴喷射速度增加时,液滴的蒸发时间、轴向以及径向蒸发距离均有所下降,但增大至一定程度后其影响作用减弱;随着液滴喷射角度的增大,液滴蒸发时间及轴向蒸发距离减小,而径向蒸发距离无显著变化。因此,在急冷塔尺寸受限时选用70 μm以下的小雾化粒径喷嘴能够直接有效提升急冷塔的运行安全性。同时,与均匀进气型急冷塔相比,采用涡壳进气型急冷塔以及喷嘴成切圆布置方式能够在急冷塔上部形成湍流强化区域,喷嘴雾化粒径为80 μm时,轴向安全裕度可提升7%。该模拟结果可为小型化急冷塔的工程应用提供优化设计方案与运行指导参考。Abstract: Aiming at small-scale quench tower in limited space, the effect of operation parameters of spray nozzle on the evaporation process was studied by using computational fluid dynamics (CFD), such as atomization droplet size, jet relocity and spray angle. The results showed that with the increase of the droplet size, the evaporation time, axial and radial evaporation distance of the droplet increased accordingly, and the evaporation time increased by 293% when droplet size increased from 40 μm to 80 μm. When the jet velocity of droplet increased, the evaporation time, axial and radial evaporation distance of the droplet decreased, but the effect was weakened when the jet velocity increased to a certain value. The increase of spray angle caused the decrease of the evaporation time and axial evaporation distance of the droplet, but there was no obvious trend on the radial evaporation distance. The small atomizing droplet size nozzle below 70 μm could directly and effectively improve the operation safety. By comparison, it was found that a turbulence intensified area was formed in the upper part of the quench tower with volute inlet, and that led to better cooling characteristic and operational safety than quench tower with upper vertical inlet, when the space of quench tower was limited. The axial safety margin could be increased by 7% with a droplet size of 80 μm. The simulation results could provide optimal design scheme and operation guidance for engineering application of miniaturized quench tower.
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Key words:
- limited space /
- quench tower /
- volute inlet /
- evaporation characteristic /
- numerical simulation
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[1] 沈祥智,严建华,白丛生,等.垃圾焚烧中污染物生成与受热面腐蚀及其控制[J].热力发电,2006(7):24-28. [2] 黄蕾,李晓东,陆胜勇,等.城市生活垃圾焚烧产生的二噁英的防治措施[J].电站系统工程,2005,21(2):5-7. [3] 陆胜勇.垃圾和煤燃烧过程中二噁英的生成、排放和控制机理研究[D].杭州:浙江大学,2004. [4] 马力,仇性启,王健,等.高温气流中液滴蒸发特性的研究[J].石油化工,2013,42(3):298-302. [5] RENKSIZBULUT M, YUEN M C. Experimental study of droplet evaporation in a high-temperature air stream[J]. Journal of Heat Transfer, 1983, 105(2):384-388. [6] HIROSHI N, YASUSHIGE, UJIIE. Experimental study on high-pressure droplet evaporation using microgravity conditions[J]. Symposium on Combustion, 1996, 26(1):1267-1273. [7] GHASSEMI H, BAEK S W, KHAN Q S. Experimental study on binary droplet evaporation at elevated pressure and temperature[J]. Combustion Science and Technology, 2006, 178(4/5/6):1031-1053. [8] RENKSIZBULUT M, YUEN M C. Numerical study of droplet evaporation in a high-temperature Stream[J]. Journal of Heat Transfer, 1983, 105(2):99-106. [9] KINCAID D C, LONGLEY T S. A water droplet evaporation and temperature model[J]. Transactions of the ASAE, 1989, 32(2):457-463. [10] 冉景煜,张志荣.不同物性液滴在低温烟气中的蒸发特性数值研究[J].中国电机工程学报,2010,30(26):62-68. [11] 张志荣,冉景煜.废水液滴在低温烟气中的蒸发特性数值研究[J].环境工程学报,2011,5(9):2048-2053. [12] WANG B, LI H L, YAN J Y, et al. Modelling the quench tower in flue gas cleaning of a waste fueled power plant[J]. DEStech Transactions on Environment Energy and Earth Science, 2019(iceee). [13] LI H D, WANG B, YAN J Y, et al. Performance of flue gas quench and its influence on biomass fueled CHP[J]. Energy, 2019, 180:934-945. [14] 詹仕巍,虞斌.急冷塔内喷雾蒸发过程的数值模拟[J].轻工机械,2017,35(6):87-91,96. [15] 李谈教.影响蒸发急冷塔湿壁腐蚀的因素分析[J].上海化工,2019,44(5):18-21. [16] 郭慧媛.医疗垃圾焚烧烟气急冷塔喷雾流场优化及工程应用[D].西安:西北大学,2017. [17] 张天琦,杨宏伟,葛剑,等.基于CFD的急冷塔雾化喷枪数值计算[C]//《环境工程》2019年全国学术年会论文集,2019:4. [18] GOSWAMI A, KUMAR S. Failure of water quench tower in an ethylene cracking plant-ScienceDirect[J]. Engineering Failure Analysis, 2020, 118:104857. [19] 胡少龙,黄培培,杨吉涛,等.垃圾焚烧尾气处理急冷塔优化设计[J].中国环保产业,2018(8):37-38,42. [20] 盛锴.危险废物焚烧系统烟气急冷塔的数值模拟研究[D].杭州:浙江大学,2008. [21] 李坦,靳世平,黄素逸,等.流场速度分布均匀性评价指标比较与应用研究[J].热力发电,2013,42(11):60-63,92.
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