摘要
本研究根据圆筒型管式加热炉自身的特点和结构,结合四角切圆和旋流的燃烧方式,提出一种在螺旋向上的,旋流中央增加锥形的辐射墙来强化辐射传热的燃烧方式。通过搭建小型的圆筒型管式炉的小试装置进行了单直喷,四小直喷,旋喷的热态传热对比试验,在无换热介质的传热实验中,发现无论是大石油液化气流量还是小石油液化气流量,旋流燃烧的效果明显好于其它燃烧方式。在以水为换热介质的有载荷传热实验中,旋流燃烧方案仍然好于其它方案,水管的出水温度更高,排烟温度更低。
通过对单直喷,四小直喷以及旋喷三种流动方式的冷态数值模拟,得到了三种不同流动方式的速度场,发现旋流喷射器的4个燃烧器以45°倾斜向上的布置,形成了旋转的涡旋,增强了燃料助燃空气的混合,同时稳定了气流,增加燃料和助燃气在炉膛内的停留时间。旋流燃烧器中辐射锥的设置起到了导流的作用,使得流体由中心向周围扩展,锥形的设计使得流体扩展的直径逐渐变大,同样起到增加流体在炉膛内停留时间的作用。
通过对四小直喷和旋喷两种燃烧方式的热态三维数值模拟,发现试验测得炉膛内的不同位置设置测温点测得的温度垂直分布曲线与数值模拟得到的相同位置的温度分布曲线,曲线变化的趋势接近,出口烟气的温度值误差较小。通过对比两种不同燃烧方式的数值模拟结果,发现旋喷燃烧的温度场分布比短焰直喷的直流燃烧方式均匀,炉膛底部辐射锥的导流作用明显,火焰既没有舔到炉管,又使得高温烟气更接近四周的炉管,直接强化了炉膛中下部的传热。而旋流燃烧由于旋流产生的涡旋作用,不仅增加了燃料和助燃空气在炉膛中下部的停留时间,并且增加了高温烟气在炉膛内的停留时间,降低了排烟温度。
A new way of swirling combustion was presented in this paper. A radiant tapered wall was placed in the center of the swirl in order to enhance the heat transfer.
A compare experiment was made between traditional combustion method and the swirl combustion method. The result showed that the swirl played a more effective part in combustion. The heat transfer was improved in the middle and at the bottom of furnace and the temperature of outer smoke drops. The same result was also got using water as the heat transfer fluid.
This paper also presented numerical simulation results of traditional and new swirling fluid flow. The velocity field showed that mixing homogeneity were improved, retention time of the fuel and air were extended by the swirl. The flow-guide characteristics of the tapered wall showed its superiority.
Three dimensional numerical simulations of the four direct bottom up combustion and swirling combustion method were made for the radiant section of furnace. The results with the models were in well agreement with the measurements of temperature from top to down. The different methods were comparable. It was showed that temperature field distribution of the swirling method was much better.. The radiant tapered wall not only keep proper distance to the pipe, but also guide the high temperature gas around the pipe, so the heat transfer in the middle and at the bottom of the furnace was directly improved. The swirl also extend the high temperature smoke's retention time at the top of the furnace, enhanced the heat transfer without question, and dropped the temperature of outer smoke.
引文
铩颷1]陈树义,章丽玲.燃料燃烧及燃烧装置.北京:冶金工业出版社.1985
[2]何英介.工业炉节能技术.济南:山东科学出版社.1984
[3]赵易成.实用燃烧技术.北京:冶金工业出版社.1982
[4]赖周平.畜热燃烧技术在石油化工管式加热炉应用的前景分析.化工进展,2006,25:344-347
[5]程远铭,王允从,潘爱军等.管式加热炉的改进措施及工艺优化.河南化工,2006,23(10):43-44
[6]张纯洁,阙连胜.油田管式加热炉低温腐蚀的探讨.油田地面工程,1991,10(5):42-44
[7]徐国宝.圆筒管式加热炉烟气余热回收技术改造.能源技术,1991,10:56-57
[8]梁贵波,薛长泉.管式加热炉节能技术.油气田地面工程,2004,23(5):30
[9]蔡晓军,王建军.管式加热炉节能改造.化工设备与管道,2002,39(2):19-20
[10]钱家麟,于遵宏,玉兰田.管式加热炉.北京:烃加工出版社.1987
[11]周志军,林震,苟湘等.文丑里浓淡煤粉燃烧器的分离特性和阻力特性研究.热力发电,2006,35(11):11-13
[12]赵伶玲,周强泰,赵长遂等.花瓣燃烧器流场特性分析于研究.燃烧科学于技术,2007,13(1):1-24
[13]刘泰生,叶恩清,陈灿等.百叶窗式水平浓淡燃烧器叶片结构改进的试验和数值模拟研究.中国电机工程学报,2003,23(6):213-216
[14]浙江大学,岑可法,樊建人.燃烧流体力学.水利电力出版社出版,1991
[15]Lobo W.E.,Even J.E.,Heat transfer in the radiant Section of Peroleum Heaters,Trans.AIChE,1939,35:743
[16]佐野司朗.管式加热炉设计,化学工场(日),1962(4),5
[17]Lobo W.E.,Design of furnaces with flue Gas temperature gradients.Chemical EngineeringProgress,1974,70(1):65-71
[18]Hottel H.C.,Cohen E.S.,Radiant heat exchange in a gas filled enclosure:Allowance forNon-uniformity of Gas Temperature..AICHE,1958,1(1):3-14
[19]Hottel H.C.,Sarofim A.F.,Radiative Transfer.McGraw-Hill Book Company,1967
[20]Howell R.J.,Monte carlo Application in heat transfer.Advance in Heat Transfer,1968
[21]Steward F.R.,Cannon P.Int of Heat and Mass Transfer 14;245-262
[22]Roesler F.C.,Theory of Radiative heat transfer in co-current tube Furances,ChemicalEngineering Science,1967,22:1325-1336
[23]Gosman A.D.,Pun W.M.,Heat and Mass transfer in recirculating flows.AcadimicPress,1969
[24]萧家治,杨光炯,黄祖祺.管式圆筒炉辐射室二维流场和温度场的研究.化工学报,1990,2(1):147-153
铩颷25]刘振法,黄祖祺,杨光炯.圆筒型原油加热炉炉膛内速度场及温度场的模拟.化工学报,1991,4(1):416-422
[26]饶利波,杨光炯.方型多火嘴石油化工管式炉中辐射室三维流动及传热的数学模拟.化工学报,1993,44(4):410-417
[27]周桂娟,毛羽,王娟.圆筒炉内燃烧器出口湍流流动和燃油燃烧的三维数值模拟.石油学报,2006,22(4):49-55
[28]须文波,朱继红.管式加热炉对流受热面的吹灰优化研究.石油与天然气化工,2006,35(1):34-37
[29]袁龙春,冷鑫宁,赵强.吹灰器在直接管式加热炉上的混合使用.仪器仪表用户,2007,14(6):132-133
[30]车俊铁,刘录.管式加热炉常用高温炉管性能对比分析.工业炉,2002,24(3):11-14
[31]王福军.计算流体动力学分析-CFD软件原理与应用.北京:清华大学出版社,2004
[32]H.K.Versteeg,W.Malalasekera,.An introduction to computational fluid dynamics:Thefinite Volume method,New York:John Wiley & Sons Jnc.1995
[33]V.Yakhot,S.A.Orzag,Renormalization group analysis of turbulence:basic theory.J.ScientComput.1986,1:3-11
[34]卡里尔.燃烧室与工业炉的模拟.北京:科学出版社,1987
[35]韩昭沧.燃料与燃烧.北京:冶金工业出版社,1994
[36]张松寿.工程燃烧学.上海:上海交通大学出版社,1987
[37]周力行.湍流两相流动与燃烧数值模拟.北京:清华大学出版社,1991
[38]王应时,范维澄,周力行,徐旭常等。燃烧过程数值模拟.北京:科学出版社,1986
[39]于亚丽.300MW机组旋流式燃烧器得试验研究与数值模拟:[硕士学位论文].河北保定:华北电力大学动力工程系,2006