第23卷,第4期中國鐵道科學2002年8月CHINA RAILWAY SCIENCEAugust, 2002文章編號:1001-4632(2002)04013207博士論文摘要列車空氣動力學數(shù)值仿真研究武青海鐵道科學研究院機輛所,北京100081)關鍵詞:列車空氣動力學;有限體積法;湍流模型;磁懸浮列車中圖分類號:U260.111:V211.3文獻標識碼:A限差分法、有限單元法和有限體積法)1前言對于列車空氣動力學,與傳統(tǒng)的試驗研究方法相比數(shù)值仿真技術方法可以隨時隨意給定所需參數(shù)自從20世紀60年代,日本建成時速達210km進行仿真計算,并利用計算結果選擇最佳設計,從的東海道新干線以來,世界鐵路的高速化技術得到而節(jié)省人力、物力、財力,縮短產品設計周期。還迅速發(fā)展,使得鐵路運輸在經(jīng)濟發(fā)展中再次發(fā)揮了有工程中遇到的反問題,諸如要求預先給定流動結重要作用。2001年,法國建成了運營速度達300km果,然后通過計算來確定物面形狀,而這些都是試h-的地中海線,將世界鐵路的高速化進程又推向驗所無法做到的?？梢哉f,對于解決工程問題,仿個新的高潮。真計算可以幫助選型,減少設計費用,縮短設計周隨運行速度提高,空氣阻力等列車空氣動力學期。并且對于某些特殊問題,仿真計算還可以代替問題日益受到重視。因此為實現(xiàn)高速鐵路的安全、試驗。因此本文采用了數(shù)值仿真方法來研究列車空舒適、降低能耗并滿足環(huán)境保護的要求,世界各國氣動力學問題。逐漸開展了對列車空氣動力學問題的研究,并在此這其中有限體積法在列車空氣動力學數(shù)值仿真基礎上形成了一個獨立的學科——列車空氣動力研究中有著其它計算方法無法比擬的優(yōu)勢,并且也學是計算流體力學中目前最為流行的計算方法,因此列車空氣動力學問題可以分為以下幾類:空氣本文采用了有限體積法進行列車空氣動力學數(shù)值仿阻力;側向風的空氣動力學特性;會車時作用在列真計算。車上的氣動壓力;列車風;隧道內的壓力波動;隧道出口微氣壓波;車體表面湍流邊界層的壓力變3理論基礎及數(shù)值計算方法動我國在此方面的研究起步較晚,90年代初才正列車是一個長寬比很大的細長物體,形狀比較式開始,起初主要是進行實車試驗及風洞試驗;數(shù)復雜,而且近地運動,所以繞列車的空氣流動是完值仿真技術盡管與世界先進水平相差很大,但近幾全三維的流動。在列車尾部會出現(xiàn)一對很強的尾年發(fā)展速度也很迅速渦。通過列車外部流場的基本特征以及流場雷諾數(shù)來判斷其流動的形態(tài),可以知道列車外流場為湍流2列車空氣動力學主要研究方法流場I凵中國煤化工論研究及實際應用中試驗研究方法(風洞試驗、水洞試驗、電模擬都已CNMHG校滿意的結果特別是試驗實車試驗)和數(shù)值仿真研究方法(面元法、有對外部流動的研究較多。因此本文選用kε雙方程湍收稿日期:200205作者簡介方據(jù)"3-),男,河南安陽人,博士第4期博士論文摘要133流模型來研究列車空氣動力學問題?！鱵23G,△xYH2k-ε雙方程湍流模型的求解方程組由以下基本Re△y2ayRe1△z方程組成連續(xù)方程變換后得到最終形式dU dF dg dHdFdG雷諾方程H△d2+(△xm△ym△zm…)0+pax,=p、少當a3,y分別取值小于或遠小于m時所采用的網(wǎng)格和差分格式才能比較正確地計入各方向的粘性貢獻。因此在α3,γ分別取值m時就可以得到dx: a湍動能k方程臨界網(wǎng)格間距值Δx*、Δy*、△z*。Ig hIgErak, duiau'. dg△z=gRe湍流耗散率ε方程5計算域的選取2u dump在仿真計算中,一般采取有限計算域來代替無2限計算域,計算域的大小直接影響到計算結果的可dx dx: d信程度。但是對于不同類型計算對象,其計算域的ut;/u’;du’;du大小不能一概而論,所以需要具體問題具體對待。ax. ax adx: d本論文中的計算域的選取采取了試算分析的方法確au';o’oua-u'定。在對于計算域的選取中,試算方法不失為一種有效的方法數(shù)值計算方法采用有限體積法中常用的SIPE( Semi-Implicit Method for Pressure-Linked Equa6移動網(wǎng)格技術ions)求解離散方程組。在列車交會和過隧道的瞬態(tài)計算中,存在計算4貼體網(wǎng)格間距的確定對象之間的相對運動,利用移動網(wǎng)格來模擬物體之間的相對運動,可以很好地進行處理移動網(wǎng)格界面三維流動無量綱化的NS方程之間的邊界條件。dU dF aG dH在移動網(wǎng)格的一些實際應用中,計算域的大F dG aH在計算過程中有很大變化,此時在瞬態(tài)計算中可通Rell axt ay過單元移除或添加來解決上述問題,以保證計算域階精度的差分格式求解后,方程成為的完整性。dU, aF(dFr aGat t ax tRe7以 STARCD為基礎的仿真程序dHd2/+△xm△ym△m灬…)中國煤化工CNMHG件作為核心進行列車a grewIg re外部流功計算,世一個用軟件應用于具體專業(yè)時方程經(jīng)需要與其他程序一起使用以及進行必要的二次開發(fā)才能更好地為本專業(yè)服務aU3 F aG dH△xdF2o方方數(shù)據(jù)y+z=Re△xx+134國鐵道科學第23卷開始型列車頭尾的壓力差,且前者的高壓區(qū)受力區(qū)域面給定列車模型主要外形尺寸參積要大于后者,因此鈍頭型列車的頭尾壓差阻力比流線型列車的頭尾壓差阻力大得多在CAD圖形軟件中建立列車模型的主要截面數(shù)據(jù)(4)鈍頭型列車總的運行空氣阻力要大于流線通過DF格式轉換,進入UCAD程序建立三維列車模型型列車的空氣阻力。要降低列車的運行空氣阻力,輸出列車模型表面特征數(shù)據(jù),生成格式轉換文件須從優(yōu)化設計列車頭尾形狀入手,好的流線型列車形狀是降低阻力的主要有效手段進入 STARCD前處理程序將計算域合理分成若干子域,然后劃分計算網(wǎng)格10列車風計算結果進入 STARCD后處理程序采用數(shù)值仿真方法計算分析了流線型和鈍頭型云圖,編制程序從 STARCD中兩類車體周圍列車風基本特征(1)以神州號動車組為代表的流線型車體周圍編制列車空氣動力性能結果數(shù)據(jù)處理程序列車風基本特征:列車風合速度在車頭車尾各出現(xiàn)通過繪制圖表程序生成圖表個峰值,隨距地面高度增加,尾部波動要大于頭結束部的波動;車頭附近壓力場出現(xiàn)一個由正到負的壓經(jīng)過上述這樣對ARCD軟件的修正以及二次力波,且最大正壓力出現(xiàn)在車頭的前方;車尾附近開發(fā)后,可以讓工程設計人員很方便地應用該軟件有一個由負到正的壓力波,波峰出現(xiàn)在列車尾端的進行產品的前期開發(fā)和研究后方。(2)以Ss8列車編組為代表的鈍頭型車體周圍8計算模型選取與簡化列車風基本特征:列車風合速度在頭部的波動要遠大于尾部的波動;壓力場的分布規(guī)律也驗證了這為不失一般性,與實際情況相結合,選取了六點,說明頭部擾動產生的危險程度要大于尾部。種車型:DF4D,DF11,SS8,神州號,藍箭號,270通過分析列車風速度場研究分析,為確定我國kmh電動車組鐵路沿線安全距離提供了理論和科學依據(jù)。計算模型建立應遵循兩條原則物理的真實性、數(shù)學計算的可行性11列車過隧道和交會時的數(shù)值傷真就以下幾方面對列車模型進行簡化:結果采用兩動一拖模擬列車編組、簡化列車表面、簡化車體底部等。1)采用簡化模型分析了列車進入隧道到出隧道期間列車車身上的壓力變化和隧道內的壓力波9列車外部流場計算結果動特征。若計算機工作能力許可,經(jīng)精確計算,可為隧道凈空面積和橫截面形狀設計時的空氣動力學(1)對270kmh-電動車組在橫風工況下的題提供參考依據(jù)風洞試驗結果與仿真計算結果進行了比較,兩者吻(2)初步探討了列車交會時,兩列車內側車身合很好,說明采用 STARCD軟件能夠較好地描述和側壁承受了車頭車尾通過時的兩次壓力瞬變,但是研究鐵路列車空氣動力學性能。分析了六個模型車對于兩車之間流場復雜的流動杋理尚未有定論。身縱向對稱面上的壓力分布規(guī)律,從而可以定量比較流線型列車與鈍頭型列車的區(qū)別。12(2)運營速度在120kmh-1-160kmh-1范圍研究H中國煤化工動力學數(shù)值仿真CNMHG內的列車,若采用流線型車體,則與普通列車相比,可以使空氣阻力降低70%以上,從而達到降低〔1)對流場而言,不外包形狀的磁懸浮列車能耗的目的外部流場比外包形狀的要復雜,阻力系數(shù)也有所增3)鈍灰殞車車頭與車尾的壓力差大于流線大,所以流線型的外包形狀比較有利于列車周圍氣第4期博士論文摘要135體的流動。但磁懸浮列車與線路是否外包對總旳運(3)高速鐵路隧道斷面形狀及岀入口形狀的研行空氣阻力的影響不大。究(2)在對列車模型簡化的基礎上,磁懸浮列車4)隧道內部通風以及散熱等問題的運行空氣阻力計算結果比輪軌式列車大13%左5)列車交會時兩列車中間區(qū)域流場的空氣流右。因此,相同頭型和迎風截面外形的輪軌式列車動機理研究以及線間距的確定的運行空氣阻力要小于磁懸浮列車。(6)氣動噪聲問題13工作展望希望通過對列車空氣動力學的數(shù)值仿真研究,能夠建立“數(shù)值風洞”,使其在工程設計中得到廣(1)底部轉向架的近似模擬泛應用,加速發(fā)展我國的高速鐵路技術。(2)車內通風問題a Study on Numerical Simulation of Train Aerodynamicswu Qing-HaiChina Academy of Railway Sciences, Beijing 100081, Chinasure shift in tunnel the micro-pressure at tunnel exit, and1 Introductionthe pressure shift in the turbulence layer of train surfaceThis study in China is behind the world, startedAfter the first Shinkansen train in Japan run success- from actual train test and wind tunnel test at the early dayfully at 210 knt h-I in 1 960 s, the high-speed railway of 1990 s. Recently the numerical simulation techniquetechnique has been developed quickly all over the world has been developed rapidly although there is a big distanceand made railway transportation play a important role in e- between China and the worldconomic development again. In 2001, the Med Line wasbuilt in France so the high-speed technique of the world 2 Main study methods for train aerody-railway had reached a new steWith raising the train running speed, train aero-dynamIcsnamics problems have been regarded increasingly. Thestudy on train aerodynamics problems have been developedTest study method( wind tunnel test, water tunneltest electronic simulation test and actual train test ), andand comfortable of high-speed train reduce the powers numerical simulation method panel method, finite differconsume, and environmental protection. And based on encethese an independent subject, train aerodynamics has metheH中國煤化工 ethod and finite volCNMHGappearedFor train aerodynamics, compared with traditionalThe train aerodynamics can be classified as belotest study method, the simulation calculation can be madeAir drag side direction wind the air pressure on at any time when setting the required parameters. Thethe train wheh erosing, train induced airflow, the pres- best design will be selected according to the result, and it136國鐵道科學第23卷an cut down the consumption in manpower money andlL:antage of simulation method can be showed also throughTurbulence kinetic energy h equationthe anti-question in project. Such as the flow result areknown in advance then the surface shape of product willbe confirmed by calculation, while the target can not be2reached by test method. That is to say, for project probTurbulence dissipation rate E equationlems the shape can be selected, the design expense canbe reduced and the design period can be shortened alsojdx, dthrough simulation calculation And it can substitute fortest in some special problems. So the numerical simulationa∈)-2t'ujaxmethod is used to research the train aerodynamics proldu;/du’;o7u't0lems in this paperdCompared with other calculation methods the finitedu';du';Ou’volume method( FVM) has more advantage in train aerodxr dx: d.dynamics research. And it is one of the most popular calThe numerical calculation method adopts SIMPLEculation methods in CFD today. Therefore we adopt FVM( Semi-Implicit Method for Pressure-Linked Equations )ofto make the numerical simulation calculation for train FVM to solve the discredited equation setaerodynamIcs3 Theory foundation and numerical calcu- meshes near walllation method3D zero dimension N-S equationdU dF dG dHTrain has a slender body with large ratio of length towidth and complicated shape. And train runs close to thedF. dG. dHground. So the airflow around train is 3D completely. ARe, ox+ apair of strong tail vortex appears behind train. AccordinAfter m rank precision difference form solution,eto the basic characteristic of the airflow around train and quation becomesthe flow reynolds number we can know that the flow fieldau dF aG dH 1 dF aGaz Rearound train is a turbulence fieldIn theory research and application k-E turbulencea2)+△rAym△”灬)model has reached a mature degree and gotten many morelureIg Resatisfied results especially for exterior flow field. So weadopt the k-e turbulence model to study the train aerodSubstitute in the above equation and rearrangeU dF dg aH△xdF2The solution equation set of h-E turbulence modelRe1△xax+consists of the following aquatic△y2dG,△zH中國煤化工02+Continuity equationHCNMHGWe get the final expression1+3F+3+dFGa片數(shù)據(jù)a- op△z+O△xAym△znr…)第4期博士論文摘要137When a,B and y are less than m or more respectivelthe adopted mesh and difference form can include the viof traincosity contribution of each direction correctlyTherefore as a,B and are equal to m we canEstablish the main section data of train model in CAD softwareget the critical distance between meshes Ax,AyEstablish 3D train model in UGCAD by format transformOutput the surface data of train model,grelg reand create transform file withnto sTaRCd preprocedurelIgErColculation field divided into some sub-fields and5 Selection for the calculation fieldInto STARCDIn the simulation calculation people substitute theOutput flow field and pdistribution graphlimited calculation field for the infinite calculation field ingotten the result dataprogrammMinGgeneral. The size of the calculation field influences theDesign program to treat with the result data of train aerodynamicscreditable degree of calculation result directly. But for thedifferent type models their calculation field cannot beChart generated by prconsidered similarly. So specific problem should be treated especially. The calculation fields in thAfter above secondary development project plannerfirmed by the pilot calculation method. The pilot calculacan use STARCD software easily to make prophase develtionthod may be aneffective way for the calculation opment and research for productfield selection8 Selection and simplification of calcula-6 Sliding mesh techniquetion modelIn order to ensure generality six type trains are seIn the transient calculation of train crossing and trainlected: DF4D, DF11, S$8, Shenzhou, Lanjian 270 kmpassing a tunnel there is a relative movement between thehpower callculation objects. It can deal with the bounThe calculation model's establishment should followtion between the movement mesh interfaces nicely thoughIn some applications of sliding mesh, the size of cal- mathematical calculatio ity of physics and feasibility ofthe relative movement simulated by sliding meshculation field may change largely at the calculation proThe train models are simplified at the followincess. At this time we can use cell removal and addition topects according the principles: two power cars and onesolve the above problem, in order to ensure the integrality trail car used to simulate train set simplification of trainof calculation fieldsurface and the train body bottom9 The calculation result of train exterior7 Simulation program based onflow fieldSTARCD(1) After comparison, the calculation results of 270The calculation for the exterior flow around train is km.YH中國煤化工 condition of crosswind fitmade where the fluid software staRCd is considered as withC Gnel very well. It meansthe core. When general software is used to certain field, the software STARCD can describe and study the trainit should be used with other programs together or made aerodynamics betterecondary development in order to serve best for this spe-(2) For train which run at 120 kml h- -160 kth-, if a streamline body is adopted its air drag will be138中國鐵道科學第23卷less 70 than that of train with general body in order to passing tunnel and the pressure fluctuation in tunnel is anreach the target reducing power's consumeeIs. The study will provide ref-(3)The pressure differences of nose for blunt nose erence basement for the aerodynamics problems during detrain are larger than that of streamline train and the same signing tunnel area and section shape by accurate calculaas the end. The high-pressure size of the former is larger tion if the work ability of computer allowsthan that of the latter also. So the pressure differences be-(2) The sidewall of train body between two trainstween nose and end of blunt nose train is larger than that endures the pressure transient twice during trainf streamline trainBut the complicated flow mechanism between two trains is(4) The total running air drag of blunt nose train is not yet clear up to nowger than that of streamline train In order to reduce the12 Numerical simulation study of maglevgood streamline shape is main effective way to reduce airaerodynamIcs(1) For the flow field, no wrap maglev is compli-10 The calculation result of train inducedcated correspondingly compared with wrap maglev its airdrag coefficient is much larger thanof wraairflowSo the maglev with streamline wrap shape is propitious toThe basic characteristic of train induced airflow is the air flow around train but it has small influence foranalyzed with numerical simulation methodtotal air drag whether the shape between maglev and rail(1)The basic characteristic of train induced airflowaround the streamline train represented by Shenzhouhao(2)Based on the simplified model the calculationpower car set: the peak value of the resultant velocity Vxy result of maglev air drag is more than that of wheel trainappears twice at the nose and end respectively. The Vay about 13 percent. Therefore the air drag of wheel train isshift of the end is larger than that of the nose when the less than that of maglev with the same nose type and winddistances to grourise gradually. One press wave froward sectonpositive to negative appears near the train nose and themost pressure lies in front of train. Another press wave13 Work prospectfrom negative to positive appears near the train end and(1) Approximate simulation for the train bogiethe peak lies behind the train end(2) Ventilation problem inside train(2)The basic characteristic of train induced airflow(3) Study on the section shape entrance and exitaround the blunt train represented by SS8: The fluctuation shape of high-speed railway tunnelof the resultant velocity Iter than(4) Ventilation and heat emission in tunnelthat at the train end. The distribution law of pressure field(5) Study on the air flow mechanism duringalidates this point also. That is to say that the danger de- crossing and the interval between linesgree made by the nose fluctuation is larger than made by(6)Air noise problemthe train endset upBy analyzing the train-induced airflow this paper through studying train aerodynamics. Our high-speed railprovides theoretical and scientific basement for the railway way technique can be developed fast with the applicationsafety distance in China11 The simulation result of train passing KeyI Vpnd tunnel" widely in engineering design中國煤化工FVM TurbuleCNMHtunnel and crossingmoc責任編輯劉衛(wèi)華)(1) The pressure change on train body during train