《微型燃气轮机回热器燃气腔结构优化.pdf》由会员分享，可在线阅读，更多相关《微型燃气轮机回热器燃气腔结构优化.pdf（5页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、收稿日期:2005-06-23;修订日期:2005-10-19基金项目:国家“863计划”能源技术领域燃气轮机重大专项基金资助项目(2002AA503020);教育部霍英东教育基金会高等院校青年教师基金资助项目(91056)作者简介:张冬洁(1972-),女,河北遵化人,西安交通大学博士研究生.研究、试验与设计文章编号:1001-2060(2006)01-0010-04微型燃气轮机回热器燃气腔结构优化张冬洁,王秋旺,罗来勤,吴 峰(西安交通大学 动力工程多相流国家重点实验室,陕西 西安710049)摘 要:对100 kW微型燃气轮机分体式回热器燃气腔的流场做了数值模拟,分析了燃气入口管道采用不
2、同的锥度角及不同的伸入腔内长度L时对燃气腔流场的影响,分析表明,=5 及L=370 mm时,整个流程的阻力损失及各燃气出口速度均匀度综合评定为最优。关键词:分布式发电;微型燃气轮机;回热器;结构优化中图分类号:TK479 文献标识码:A1 引 言分布式发电与大电网相结合是节省投资、降低能耗、提高电力系统可靠性和灵活性的一种方式,被世界很多专家公认是21世纪电力工业的发展方向1,微型燃气轮机是目前最有竞争力的分布式发电方式2。微型燃气轮机是一种新型发动机,近年来在分布式发电 能源系统领域发展迅速。在过去的半个世纪里,大部分燃气轮机均采用简单的循环,提高燃气轮机的入口温度、压力使得燃气轮机循环效率
3、得到提高,但是由于材料和叶片冷却技术的限制,提高的幅度是有限的。要进一步提高燃气轮机效率,采用复杂的循环型式成为重要途径。不同类型的紧凑式回热器就是实现高效燃气轮机循环的一个重要设备35,它能使燃气轮机效率提高到30%以上6。紧凑式回热器换热效率大大提高,它的应用克服了回热器的体积过大、整体性差、安全性差和维修麻烦等缺点,推广了微型燃气轮机的使用。由于紧凑式回热器一般采用CC(Cross Corrugated)、CW(Cross Wavy)和CU(Corrugated Undulated)等原表面换热片,内部结构比较复杂,利用各种数值模拟软件对回热器的流场和换热特性的模拟成为优化设计的重要依据
4、之一。但是在以往的文献中一般都侧重对于不同原表面换热芯体部分的换热及阻力特性的研究,可参阅相关文献79。为了优化回热器的结构,对于芯体以外的气体通道进行流场数值模拟也具有重要意义。本文主要是对分体式回热器的燃气流程做了流动数值模拟,旨在设计和优化回热器的外形结构。图1 微型燃气轮机循环系统示意图2 回热器燃气腔结构优化2.1 计算模型的建立图1是一种现有的微型燃气轮机循环系统的示意图。微型燃气轮机循环系统主要由离心压气机、第21卷第1期2006年1月热能动力工程JOURNAL OF ENGINEERING FOR THERMAL ENERGYAND POWERVol.21,No.1Jan.,2
5、006向心透平机、燃烧室和回热器等组成。其中,回热器是一种高效紧凑式的原表面回热器,它是微型燃气轮机的关键部件,其在燃气轮机中的作用主要是:利用向心透平机中排出的废燃气对进入燃烧室之前的压缩空气进行预热,提高进入燃烧室的压缩空气温度,从而使系统实现了回热循环,提高了系统的热效率。其中分体式回热器的外形如图2所示,入口管道锥度角为,伸入腔内长度为L,燃气流经入口管道和燃气腔进入芯体,所以燃气腔出口处形成与固体壁面相间的若干矩形燃气出口。图2100 kW回热器燃气腔外形示意图 数值计算时选用100 kW燃气轮机的原表面回热器,以入口管道轴线为中心,取出一半以1:1的比例用FLUENT软件进行模拟,
6、主要优化尺寸为和L,在=35 及L=200400 mm范围内,选取若干模型,利用燃气流程总阻力损失以及各燃气出口的速度均匀度综合评定各模型的优劣,最终得到最优结构。2.2 求解器求解采用三维k-湍流模型,对于动量方程和k-方程均采用二阶迎风格式离散,利用SIM2PLE算法对压力场和速度场求解。其通用方程为:9(u)9x+9(v)9y+9(w)9z=99x(99x)+99y(99y)+99z(99z)+S(1)对于不同的变量,其对应的广义扩散系数 和源项S表示如下:(1)连续性方程:=1,=0,S=0(2)(2)动量方程:x方向:=u,=eff=+1,S=-9p9x+99x(eff9u9x)+9
7、9y(eff9v9x)+99z(eff9w9x)y方向:=v,=eff=+1,S=-9p9y+99x(eff9u9y)+99y(eff9v9y)+99z(eff9w9y)z方向:=w,=eff=+1,S=-9p9z+99x(eff9u9z)+99y(eff9v9z)+99z(eff9w9z)(3)(3)湍流动能方程:=k,=+t k,S=Gk-(4)(4)湍流动能耗散率方程:=,=Pr+t S=(c1Gk-c2)k(5)其中:分子粘性为;湍流粘性系数t=ck2;耗散率=cDK32l;Gk=t29u9x2+9v9y2+9w9z2+9u9y+9v9x2+9u9z+9w9x29v9z+9w9y2(6
8、)对各量的湍流Prandtl数及方程中涉及到的系数ci按经验取值10。利用FLUENT软件模拟流场时,固体壁面采用壁面边界(Wall),对称面采用对称边界(Symmetry),入口选用速度边界(Velocity Inlet Boundary Condi2tion),出口处为速度局部单向化(Outflow)11。图3 计算模型的网格生成图2.3 网格生成回热器燃气腔结构很不规则,生成网格时分割成几个体完成,满足不同位置对于网格类型和疏密的不同要求。为了保证计算的准确性,整个燃气腔11第1期张冬洁,等:微型燃气轮机回热器燃气腔结构优化 大部分网格采用六面体(hex)形式,只有极少选用四面体(Tet
9、Hybird)形式。网格数目在120万个左右,如图3所示。3 计算结果整理燃气是以一定的压力和流量流入燃气腔入口通道的,换热主要发生在芯体部分,故本文不考虑换热。衡量结构优劣的标准有两个,一个是整个燃气流程的压力损失;一个是燃气腔各燃气出口的速度均匀度,由于燃气出口很多,在评判燃气出口速度均匀性时,引入速度不均匀度Su参数,得:Su=Ni=1(u-um)2(N-1)um(7)其中:u-各燃气出口的速度,ms;um-燃气出口速度的平均值,ms;N-燃气出口的个数。图4 燃气出口速度不均匀度变化图5 燃气腔阻力损失变化燃气腔入口管道的尺寸由燃气轮机排气参数决定,直径为220 mm,管道出口直径和伸
10、入长度受限于回热器的整体尺寸,所以锥度角 变化范围为3 5,伸入长度L变化范围是200400 mm。它们的变化引起了腔内流场的变化。当L取200 mm,300 mm,340 mm,370 mm和400 mm时,对应每个长度值都选取=3、4、5 三个角度建立模型,并进行数值模拟。图4反映了燃气出口速度的不均匀度变化,图5反映了的燃气腔阻力损失变化。图4表明,L=370 mm,=4 及5 时,燃气出口速度不均匀度都较小,但是阻力损失值偏大,比起最小值来升高了40%多。L=400 mm,=5 时及L=200 mm,=3 时,阻力损失值都较小,但是燃气出口速度不均匀度却很高,分别是28%和26.8%。
11、图6和图7分别是L=400 mm,=3 和L=370mm,=5部分燃气出口速度矢量图,它反映了最优结构出口速度的均匀性,与较差的结构形式之间形成鲜明的对比。图6 燃气出口速度矢量图(L=400 mm,=3)图7 燃气出口速度矢量图(L=370 mm,=5)图8 对称面流场分布图(L=370 mm,=5)21热能动力工程2006年回热器的阻力损失主要集中在芯体部分,燃气腔的阻力损失只是它的3%4%12,所以燃气各出口速度的均匀性应该作为主要的衡量指标,在均匀性较好的情况下选用阻力较小的结构。计算结果表明,伸入长度L=370 mm,=5 时,燃气腔流场最为合理,结构最为优化。图8和图9分别为L=3
12、70 mm,=5 时对称面流场分布及燃气腔进出、口的速度分布图。图9 燃气腔流场分布图(L=370 mm,=5)4 结 论本文通过对100 kW燃气轮机回热器燃气腔的数值模拟结果的分析,得到如下结论:(1)通过对燃气出口速度均匀度及整个燃气腔阻力损失的综合评定,确定了L=370 mm,=5 时结构为最优。(2)通过多种结构的计算,在燃气出口处,速度均匀度均不能达到非常理想,即使是模拟出的最优结构,Su的值也有7.5%。这表明这种燃气腔的结构型式有待改进。(3)计算得到的速度场为改善燃气出口速度均匀度提供了依据。参考文献:1 朱成章.发展直燃式空调机对电力工业的作用J.华东电力,2000,28(
13、5):27-28.2 梁才浩,段献忠.分布式发电及其对电力系统的影响J.电力系统自动化,2001,25(12):53-56.3MCDONALD C F.The increase role of heat exchangers in gas turbineplants A.Proceedings of ASME Cogenturbo Congress-IGTIC.New Y ork:ASME,1989.89-103.4MCDONALD C F.Heat exchanger ubiguity in advanced gas turbine cy2clesA.Proceedings of ASME
14、Cogenturbo Congress-IGTI C.New Y ork:ASME,1994.681-703.5MCDONALD C F,WILSON D G.The utilization of recuperated and re2generated engine cyclesfor high efficiency gas turbines in the 21st cen2turyJ.Journal of Applied Thermal Energy,1996,16(89):635-653.6MCDONALD C F.Heat recovery exchanger technology f
15、or very smallgas turbinesJ.Int Journal of Turbo and Jet Engines,1996,13(4):239-261.7UTRIAINEN E,SUNDEN B.Numerical analysis of a primary surfacetrapezoidal cross wavy ductJ.International Journal of NumericalMethods for H eat&Fluid Flow,2000,10:634-648.8UTRIAINEN E,SUNDEN B.A numerical investigation
16、of primary sur2face rounded cross wavy ductsJ.H eat and Mass Transfer,2002,38(78):537-542.9MIRUNITI KENICHI,SUZUKI Y UJI,K ASSGI NOBUHIDE.Heattransfer and fluid flow characteristics of recuperators with oblique wavywallsJ.B H enTransactions of the Japan Society of MechanicalEngineers(Part B),2004,70
17、:2604-2611.10 陶文铨.数值传热学M.西安:西安交通大学出版社,2002.11 王福军.计算流体力学分析-CFD软件原理及应用M.北京:清华大学出版社,2004.12WANGQ W,LUOL Q,LIANGH X,et al.Experimental investigationon heat transfer and pressure drop in a microtubine recuperator withcross2wavy primary surface channels R.ASME Turbo Expo 2005,GT2005-68255.(渠源 编辑)能源利用90 M
18、W烧高炉煤气的联合循环装置据 Gas Turbine World2005年78月号报道,河北省邯郸钢铁厂已从日本三菱重工订购两台燃烧高炉煤气的燃气轮机,用于厂内的联合循环项目,计划于2006年8月投入使用。邯郸钢铁厂的订单要求MHI(三菱重工)提供两台30 MW的M251S型燃气轮机。MHI将负责它们的设计和制造并与杭州汽轮机厂合作组装这些装置,后者将供应30 MW的汽轮机。装置的其它部件,诸如余热锅炉、钢结构件和箱装体、进排气管将由邯郸钢铁厂在当地采购。在历史上,中国的大多数钢铁厂已经使用由锅炉和汽轮机组成的传统的电力生产系统,但是最近有转换到建造燃烧高炉煤气的联合循环发电装置的趋势。(吉桂
19、明 供稿)31第1期张冬洁,等:微型燃气轮机回热器燃气腔结构优化 炭黑与NO还原反应的研究综述=An Overviewof the Research on Reduction Reactions Involving Soot and NO刊,汉XU Bin,XIE Guang2lu,FAN Wei2dong,et al(Institute of Mechanical&Power Engineering under theShanghai Jiaotong University,Shanghai,China,Post Code:200240)Journal of Engineering for
20、Thermal Energy&Power.-2006,21(1).-14,9Over the last three decades reduction reactions involving soot and NO have attracted the attention of environmental re2search workers worldwide.The authors have given an overviewof the recent research progress on the above2mentioned re2duction reactions with an
21、emphasis on the reduction reaction mechanism of pure NO and soot.The experimental instru2ments nowadays being often used are discussed.Various kinds of reaction instrumentation can be employed for differentranges of reaction2temperature and the various products thus obtained as a result of the NO2so
22、ot reaction are also quitedifferent.At low temperatures(less than 300)an adsorption reaction will mainly take place,while at high tempera2tures a reduction reaction occurs.Finally,a brief description is given of the impact of the different atmospheres and thepresence of catalysts on reaction results
23、.Different reaction atmospheres will have different impacts on NO2soot reactions.All substances,which promote the generation of an activated potential on a soot surface,can invariably be conducive tothe progress of reactions.Key words:natural gas,soot,nitric oxide,desorption,surface base groups氦气轮机装
24、置的高温材料=High2temperature Materials for Helium G as Turbines 刊,汉JI Gui2ming,WANGChong(Harbin No.703 Research Institute,Harbin,China,Post Code:150036)Journal of Engineering forThermal Energy&Power.-2006,21(1).-59Due to its operatingfeatures a helium gas turbine is constrained in its use of construction
25、 materials,which must cope withspecific operating conditions,environmental and maintenance service factors.The key problems to be considered duringmaterial selection include:long creep life,high2temperature corrosion and radiation effects.Briefly described are the ma2jor candidate materials used for
26、 the parts and components,such as blades,discs,stators and shafting,of HTGR2GT(high2temperature gas cooled reactor2helium gas turbine)based power generation plants.It is noted that oriented crys2tallization and single crystal nickel2based alloys with protective coatings are the best candidate materi
27、alsfor turbine bladesof currently prevalent operating parameters.As for the design scheme of a cooled disc,nickel2based super heat2resistantalloys are considered eligible materials.For use at temperatures below 600alloy IN 718 can be selected with U720LIand MA6000 being destined for still higher tem
28、peratures.Key words:helium gas turbine unit,high2temperature alloy,turbine,blade,disc微型燃气轮机回热器燃气腔结构优化=Configuration Optimization of the Recuperator G as2cavity of a MicroG as Turbine 刊,汉ZHANGDong2jie,WANGQiu2wang,LUO Lai2qin,et al(State Key Laboratory of MultiphaseFlows under the Xian Jiaotong Unive
29、rsity,Xian,China,Post Code:710049)Journal of Engineering for ThermalEnergy&Power.-2006,21(1).-1013A numerical simulation was conducted for the gas2cavity flow field of the split2body type recuperator of a 100 kW microgas turbine along with an analysis of the impact on the gas cavity by such factors
30、as the use of different cone anglesatthe gas inlet piping and different lengths L of protrusion into the cavity.The results of the simulation indicate that when=5and L=370 mm,the resistance losses of the flow path as a whole and the uniformityof velocities at various gasoutlets have been comprehensi
31、vely evaluated as having achieved optimum values.Key words:distributed power genera2tion,micro gas turbine,recuperator,configuration optimization燃气轮机湿空气回注循环分析=An Analysis of the G as Turbine Humid2air Injected Cycle 刊,汉WEN Xue2you,LU Ben,LI Ming2jia(Harbin No.703 Research Institute,Harbin,China,Post
32、 Code:150036)Journal of Engi2neering for Thermal Energy&Power.-2006,21(1).-1418A gas turbine humid2air injected cycle is discussed with the assertion that there are two kinds of injected cycle,namely,internal and external humid air injection.On the basis of a partial regenerative steam injected gas turbine(PRSTIG)cy2301第1期英 文 摘 要