劉峰,姚松,張潔,張娜(中南大學(xué) 交通運(yùn)輸工程學(xué)院,軌道交通安全教育部重點(diǎn)實(shí)驗(yàn)室,湖南 長(zhǎng)沙,410075)
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動(dòng)車組橫風(fēng)環(huán)境下的交會(huì)氣動(dòng)效應(yīng)
劉峰,姚松,張潔,張娜
(中南大學(xué) 交通運(yùn)輸工程學(xué)院,軌道交通安全教育部重點(diǎn)實(shí)驗(yàn)室,湖南 長(zhǎng)沙,410075)
摘要:采用三維、可壓縮、非定常N?S方程的數(shù)值計(jì)算方法,對(duì)8輛編組的動(dòng)車組在20 m/s橫風(fēng)下以250 km/h速度交會(huì)時(shí)列車表面瞬變壓力和車體所受氣動(dòng)力及力矩進(jìn)行分析,并采用間接驗(yàn)證方法,將風(fēng)洞實(shí)驗(yàn)、動(dòng)模型實(shí)驗(yàn)得到的結(jié)果分別與數(shù)值模擬結(jié)果進(jìn)行對(duì)比。研究結(jié)果表明:間接驗(yàn)證方法下所得氣動(dòng)效應(yīng)實(shí)驗(yàn)結(jié)果和數(shù)值模擬結(jié)果變化規(guī)律一致,壓力幅值相對(duì)誤差在 5%以內(nèi);動(dòng)車組橫風(fēng)下交會(huì)時(shí),車體頭、尾處測(cè)點(diǎn)壓力差別較大,中部位于同側(cè)測(cè)點(diǎn)壓力差異較小,同一高度、不同縱向測(cè)點(diǎn)的壓力變化波形及幅值基本一致,車體頂部測(cè)點(diǎn)壓力始終為負(fù);對(duì)于車體所受橫向氣動(dòng)力及傾覆力矩,頭車比中間車和尾車的大,背風(fēng)車比迎風(fēng)車的大;隨著橫風(fēng)風(fēng)速的增加,列車所受橫向氣動(dòng)力及傾覆力矩峰值也迅速增加,嚴(yán)重威脅著動(dòng)車組的安全運(yùn)行。
關(guān)鍵詞:動(dòng)車組;橫風(fēng);交會(huì);風(fēng)洞實(shí)驗(yàn);動(dòng)模型實(shí)驗(yàn);氣動(dòng)效應(yīng)
動(dòng)車組高速交會(huì)時(shí),交會(huì)側(cè)的空氣壓力發(fā)生突變,產(chǎn)生瞬態(tài)壓力沖擊,會(huì)對(duì)車體鋼結(jié)構(gòu)、側(cè)窗和車體橫向穩(wěn)定性帶來(lái)不利影響[1?3]。交會(huì)過(guò)程中若遭遇較大的橫風(fēng),可使交會(huì)壓力波幅值增加,列車將承受更大的橫向沖擊載荷[4?5]。我國(guó)地形及氣象條件比較復(fù)雜,不少行車區(qū)段已處于強(qiáng)風(fēng)區(qū),而隨著高速鐵路的不斷發(fā)展,強(qiáng)風(fēng)區(qū)內(nèi)動(dòng)車組交會(huì)不可避免[6]:因此,研究動(dòng)車組橫風(fēng)下交會(huì)時(shí)的氣動(dòng)效應(yīng)具有很強(qiáng)的現(xiàn)實(shí)意義。對(duì)于橫風(fēng)效應(yīng)和列車交會(huì)問題,國(guó)內(nèi)外學(xué)者開展了諸多數(shù)值模擬研究[7?14],但將二者進(jìn)行耦合分析即同時(shí)考慮列車橫風(fēng)環(huán)境下發(fā)生交會(huì)的研究較少。為此,本文作者以國(guó)內(nèi)處于風(fēng)區(qū)中的某客運(yùn)專線高速鐵路為研究對(duì)象,采用數(shù)值模擬方法對(duì)動(dòng)車組在橫風(fēng)下以250 km/h 速度交會(huì)時(shí)的車體表面測(cè)點(diǎn)壓力、車體所受橫向氣動(dòng)力及傾覆力矩變化進(jìn)行分析,為動(dòng)車組在風(fēng)區(qū)內(nèi)交會(huì)安全性提供氣動(dòng)依據(jù)。另外,對(duì)于列車橫風(fēng)下交會(huì)這種復(fù)雜工況,采用的數(shù)值模擬方法很難通過(guò)實(shí)驗(yàn)手段進(jìn)行直接驗(yàn)證。據(jù)文獻(xiàn)[15],在對(duì)物理假說(shuō)進(jìn)行驗(yàn)證時(shí),對(duì)于受實(shí)驗(yàn)水平的限制暫時(shí)達(dá)不到要求的情況,可以采用間接驗(yàn)證的方法?;谶@一思路,采用風(fēng)洞模型實(shí)驗(yàn)和動(dòng)模型實(shí)驗(yàn),將動(dòng)車組單列橫風(fēng)下運(yùn)行、2 列無(wú)風(fēng)下交會(huì)運(yùn)行的動(dòng)車數(shù)值計(jì)算結(jié)果與實(shí)驗(yàn)結(jié)果分別進(jìn)行對(duì)比,以間接驗(yàn)證本文所采用數(shù)值計(jì)算方法的可行性。
依照所選列車及線路的實(shí)際幾何特征,建立列車橫風(fēng)交會(huì)數(shù)值計(jì)算模型。交會(huì)列車選用國(guó)內(nèi)高鐵線路上較常見的2款動(dòng)車組,為了與實(shí)際運(yùn)營(yíng)盡量一致,列車模型均采用8輛編組,即頭車、6 節(jié)中間車和尾車,2款動(dòng)車組全長(zhǎng)分別為201.4 m和205.2 m。根據(jù)“鐵路200~250 km/h 既有線技術(shù)管理辦法”,動(dòng)車組在環(huán)境風(fēng)速不大于20 m/s時(shí)可以正常速度運(yùn)行,本文選擇動(dòng)車組交會(huì)速度為250 km/h,環(huán)境風(fēng)速為20 m/s,風(fēng)向角為90°。交會(huì)開始前2車頭相距100 m,線間距為5m??拷鼨M風(fēng)入口的列車為迎風(fēng)車,離橫風(fēng)入口較遠(yuǎn)的列車為背風(fēng)車。采用混合網(wǎng)格對(duì)計(jì)算區(qū)域進(jìn)行離散,即在幾何外形復(fù)雜的列車周圍區(qū)域采用非結(jié)構(gòu)網(wǎng)格,其他區(qū)域采用結(jié)構(gòu)化網(wǎng)格。同時(shí)加密列車周圍網(wǎng)格密度,遠(yuǎn)離車體網(wǎng)格采用稀疏網(wǎng)格,密網(wǎng)格和稀疏網(wǎng)格之間以一定的增長(zhǎng)因子均勻過(guò)渡。計(jì)算區(qū)域和計(jì)算網(wǎng)格分別如圖1和圖2所示。
圖1 計(jì)算區(qū)域Fig.1 Computational zone
圖2計(jì)算網(wǎng)格Fig.2Computational mesh
基于三維、非定常、可壓縮、黏性流場(chǎng)對(duì)動(dòng)車組橫風(fēng)下交會(huì)進(jìn)行流場(chǎng)數(shù)值分析,采用工程上應(yīng)用廣泛的k?ε湍流模型,時(shí)間步長(zhǎng)為0.005 s,詳細(xì)流場(chǎng)控制方程及湍流模型見文獻(xiàn)[16]。為了得到穩(wěn)定初始流場(chǎng),先讓列車靜止,加載橫風(fēng),待風(fēng)場(chǎng)充分發(fā)展后再啟用滑移網(wǎng)格使列車運(yùn)動(dòng)。采用分區(qū)對(duì)接滑移網(wǎng)格技術(shù),即在有相對(duì)運(yùn)動(dòng)的不同網(wǎng)格間設(shè)置公共滑移界面,從而實(shí)現(xiàn)彼此的數(shù)據(jù)交換。為了對(duì)車體表面瞬變壓力進(jìn)行分析,在動(dòng)車組表面布置多個(gè)測(cè)點(diǎn)。迎風(fēng)車與背風(fēng)車布點(diǎn)方式一致,單列車共66個(gè);頭車和尾車測(cè)點(diǎn)布置位置相同,且數(shù)量相對(duì)較多;車體中部壓力變化較小,所以,只在每節(jié)中間車的同一截面布置5個(gè)測(cè)點(diǎn)。具體布點(diǎn)方式如圖3所示。
圖3 動(dòng)車組模型測(cè)點(diǎn)布置圖Fig.3 Points arrangement of EMU model
2.1動(dòng)車組表面壓力變化
當(dāng)動(dòng)車組無(wú)風(fēng)交會(huì)、車體表面測(cè)點(diǎn)壓力在對(duì)方頭車鼻尖到達(dá)時(shí),會(huì)產(chǎn)生1個(gè)正、負(fù)脈沖,即頭波;在最大負(fù)脈沖出現(xiàn)后開始等幅波動(dòng),直到對(duì)方尾車鼻尖通過(guò)時(shí),則會(huì)產(chǎn)生1個(gè)負(fù)、正脈沖,即尾波。由于本文選用動(dòng)車組編組較長(zhǎng),故尾波幅度遠(yuǎn)小于頭波幅度[17]。
當(dāng)動(dòng)車組交會(huì)發(fā)生在橫風(fēng)下時(shí),流場(chǎng)則會(huì)同時(shí)具有橫風(fēng)特性和交會(huì)特性。一方面,橫風(fēng)會(huì)改變動(dòng)車組表面尤其是頭尾區(qū)域原有的壓力分布,致使交會(huì)壓力波也發(fā)生相應(yīng)改變。以迎風(fēng)車車頭為例,橫風(fēng)作用會(huì)使車頭表面正壓區(qū)朝逆風(fēng)向偏移,負(fù)壓區(qū)朝順風(fēng)向偏移,因此,當(dāng)背風(fēng)車車身測(cè)點(diǎn)與其發(fā)生交會(huì)時(shí),單由交會(huì)所產(chǎn)生的頭波正脈沖被削減,負(fù)脈沖被加強(qiáng)。另一方面,2 列動(dòng)車組在橫風(fēng)下交會(huì)時(shí),由于彼此之間具有擋風(fēng)作用,使的車體表面壓力幅值會(huì)產(chǎn)生進(jìn)一步改變。圖 4所示為動(dòng)車組橫風(fēng)下交會(huì)時(shí)車體表面的壓力分布。
圖4動(dòng)車組橫風(fēng)下交會(huì)車體表面壓力云圖Fig.4PressureContour of EMU in passing each other underCrosswind
圖5和圖 6所示分別為迎風(fēng)車、背風(fēng)車車身中部測(cè)點(diǎn)(21號(hào)測(cè)點(diǎn))的壓力變化曲線。從圖5和圖6可以看出:由于橫風(fēng)和交會(huì)壓力波的雙重作用,動(dòng)車組橫風(fēng)交會(huì)時(shí)車體表面測(cè)點(diǎn)壓力與無(wú)風(fēng)交會(huì)時(shí)有明顯不同;對(duì)于迎風(fēng)車車體交會(huì)側(cè)測(cè)點(diǎn),與無(wú)風(fēng)交會(huì)相比,壓力頭波正波幅值較大,負(fù)波幅值較??;而壓力尾波正波幅值較小,負(fù)波幅值較大;頭、尾波之間的區(qū)間段壓力波動(dòng)差別不大;對(duì)于背風(fēng)車車體交會(huì)側(cè)測(cè)點(diǎn),幅值較大的為頭波負(fù)波和尾波正波;非交會(huì)側(cè)壓力主要受橫風(fēng)影響,有風(fēng)與無(wú)風(fēng)時(shí),測(cè)點(diǎn)壓力幅值有一定的變化,而交會(huì)頭波和尾波帶來(lái)的幅值變化較小。近(4號(hào)測(cè)點(diǎn)),分別為?1.76 kPa和2.37 kPa。尾車測(cè)點(diǎn)壓力幅值相對(duì)較小,鼻尖壓力(66 號(hào)測(cè)點(diǎn))最大值及峰峰值分別為0.30 kPa和0.54 kPa。
圖5 迎風(fēng)車車身中部測(cè)點(diǎn)壓力變化曲線Fig.5 Curves of pressure for measuring points in the middle of upwind vehicle
圖6 背風(fēng)車車身中部測(cè)點(diǎn)壓力變化曲線Fig.6 Curves of pressure for measuring points in the middle of leeward vehicle
2.2動(dòng)車組壓力變化幅值
圖7所示為動(dòng)車組頭車對(duì)稱面上不同位置測(cè)點(diǎn)(見圖3)的壓力變化曲線。從圖7可以看出:在同一時(shí)刻,頭車鼻尖與車身過(guò)渡處壓力相差4.00 kPa左右;動(dòng)車組橫風(fēng)下交會(huì)時(shí),除車體交會(huì)側(cè)與非交會(huì)側(cè)壓力幅值差異較大外,頭、尾車由于曲率變化較大,其測(cè)點(diǎn)壓力幅值差異也比較大。以迎風(fēng)車車體表面測(cè)點(diǎn)壓力為例,交會(huì)過(guò)程中車體表面最大正壓發(fā)生在車頭鼻尖附近(1號(hào)測(cè)點(diǎn)),為3.55 kPa,最大負(fù)壓及最大壓力峰峰值(最大值?最小值)發(fā)生在車頭鼻尖偏交會(huì)側(cè)附
動(dòng)車組中部幾何結(jié)構(gòu)相對(duì)簡(jiǎn)單,位于車體同側(cè)的測(cè)點(diǎn)壓力變化較小。圖 8所示為車體中部同一斷面不同測(cè)點(diǎn)壓力變化曲線。從圖8可以看出:對(duì)于動(dòng)車組同側(cè)的測(cè)點(diǎn),隨著車體垂向高度不同,測(cè)點(diǎn)壓力變化不大,壓力幅值及壓力峰峰值僅相差0.05 kPa左右;車體頂部測(cè)點(diǎn)壓力始終為負(fù)值,其最大正壓及峰峰值分別為?0.16 kPa和0.41kPa。沿車身不同縱向位置的測(cè)點(diǎn),由于發(fā)生交會(huì)時(shí)刻不同,使得其壓力變化也有所不同。圖9所示為車體交會(huì)側(cè)不同縱向位置測(cè)點(diǎn)壓力變化曲線。從圖9可以看出:除了相位有所不同外,各測(cè)點(diǎn)壓力變化波形及幅值基本一致。背風(fēng)車的各測(cè)點(diǎn)壓力變化波形及幅值與迎風(fēng)車的類似。
圖7 車頭不同位置測(cè)點(diǎn)壓力變化曲線Fig.7 Curves of pressure for measuring points of different locations on head surface
圖8 車體中部同一截面不同測(cè)點(diǎn)壓力變化曲線Fig.8 Curves of pressure for different measuring points in the same section of the middle of EMU
圖9 車體中部不同縱向位置測(cè)點(diǎn)壓力變化曲線Fig.9 Curves of pressure for measuring points of different longitudinal locations on the middle part of train
圖10 迎風(fēng)車所受橫向氣動(dòng)力變化曲線Fig.10 Curves of lateral force acting on upwind vehicle
2.3動(dòng)車組所受氣動(dòng)力及力矩
圖10~13所示分別為動(dòng)車組橫風(fēng)下交會(huì)時(shí),車體所受橫向氣動(dòng)力及傾覆力矩變化曲線。由于中間車所受力及力矩變化幅值相差較小,因此,只選擇第4節(jié)車進(jìn)行分析。從圖10~13可以看出:受交會(huì)壓力波的排斥、吸引作用,迎風(fēng)車所受橫向氣動(dòng)力及傾覆力矩在交會(huì)開始時(shí)先減小后增大,而在交會(huì)結(jié)束時(shí)先增大后減?。欢筹L(fēng)車在交會(huì)開始時(shí)先增大后減小,在交會(huì)結(jié)束時(shí)先減小后增大;與中間車和尾車相比,頭車所受橫向氣動(dòng)力及傾覆力矩較大;當(dāng)頭車在另一列車區(qū)段內(nèi)行駛時(shí),由于對(duì)方動(dòng)車組的擋風(fēng)作用,其所受橫向氣動(dòng)力及傾覆力矩較非交會(huì)時(shí)有所減小。
綜合比較各節(jié)車輛所受氣動(dòng)載荷,背風(fēng)車頭車所受橫向氣動(dòng)力及傾覆力矩相對(duì)最大,這是由于交會(huì)初始時(shí)產(chǎn)生的壓力頭波正脈沖與橫風(fēng)作用產(chǎn)生了疊加。表1所示為不同橫風(fēng)風(fēng)速下,動(dòng)車組以250 km/h交會(huì),背風(fēng)車頭車所受橫向氣動(dòng)力及傾覆力矩峰值。從表1可以看出:隨著橫風(fēng)風(fēng)速增加,車體所受橫向氣動(dòng)力及傾覆力矩峰值也迅速增加,當(dāng)風(fēng)速為40 m/s時(shí),背風(fēng)車頭車所受橫向氣動(dòng)力正峰值達(dá)到213.1kN,傾覆力矩正峰值達(dá)到356.2 kN?m,嚴(yán)重影響了動(dòng)車組的安全運(yùn)行穩(wěn)定性。
圖11 背風(fēng)車所受橫向氣動(dòng)力變化曲線Fig.11 Curves of lateral force acting on leeward vehicle
圖12迎風(fēng)車所受傾覆力矩變化曲線Fig.12Curves of overturning moment acting on upwind vehicle
圖13 背風(fēng)車所受傾覆力矩變化曲線Fig.13 Curves of lateral force overturning moment acting on leeward vehicle
表1 不同橫風(fēng)風(fēng)速下背風(fēng)車頭車所受橫向氣動(dòng)力及傾覆力矩峰值Table1 Lateral force and overturning moment acting on headCar of leeward vehicle underCrosswind with different speeds
3.1風(fēng)洞實(shí)驗(yàn)
風(fēng)洞實(shí)驗(yàn)在長(zhǎng)×寬×高為15 m×8 m×6 m的大型低速風(fēng)洞進(jìn)行[18]。選擇3輛編組(頭車+中車+尾車)的迎風(fēng)車動(dòng)車組為研究對(duì)象。模型縮比為1:15,合成風(fēng)速為60 m/s,側(cè)滑角分別為0°,30°,60°,70°,80° 和 90°。正式實(shí)驗(yàn)前,通過(guò)調(diào)整風(fēng)速,確保實(shí)驗(yàn)雷諾數(shù)滿足自模擬區(qū)域,即氣動(dòng)力系數(shù)、力矩系數(shù)不再隨來(lái)流速度的變化而改變。對(duì)于單車的數(shù)值模擬部分,模型縮比為1:15,合成速度為60 m/s,馬赫數(shù)Ma小于0.3,可認(rèn)為是不可壓縮流動(dòng)問題,但為了保證與模擬雙車交會(huì)時(shí)計(jì)算方法的統(tǒng)一性,按照可壓縮問題進(jìn)行處理。圖14所示為在相同來(lái)流條件下,相同外形的動(dòng)車組在平地上所受橫向氣動(dòng)力及傾覆力矩的數(shù)值計(jì)算結(jié)果與風(fēng)洞實(shí)驗(yàn)結(jié)果對(duì)比。從圖14可以看出:數(shù)值計(jì)算所得橫向氣動(dòng)力和傾覆力矩與實(shí)驗(yàn)結(jié)果變化規(guī)律一致,除 90°側(cè)滑角外,其他工況計(jì)算結(jié)果與實(shí)驗(yàn)結(jié)果相對(duì)誤差在 5%以內(nèi)。計(jì)算橫風(fēng)交會(huì)工況的側(cè)滑角并沒有涉及 90°等大角度,這說(shuō)明本文模擬橫風(fēng)所使用的計(jì)算方法是合理的。
圖14 風(fēng)洞實(shí)驗(yàn)結(jié)果與計(jì)算結(jié)果比較Fig.14Comparison between wind tunnel test results andCalculated results
3.2動(dòng)模型實(shí)驗(yàn)
采用中南大學(xué)軌道交通安全教育部重點(diǎn)實(shí)驗(yàn)室的列車氣動(dòng)性能動(dòng)模型實(shí)驗(yàn)裝置,驗(yàn)證本文對(duì)于動(dòng)車組無(wú)風(fēng)交會(huì)時(shí)氣動(dòng)效應(yīng)模擬的有效性。該實(shí)驗(yàn)裝置可以真實(shí)再現(xiàn)動(dòng)車組高速交會(huì)時(shí)的空氣三維非定常流動(dòng)現(xiàn)象,是模擬列車交會(huì)氣動(dòng)問題的專用大模型實(shí)驗(yàn)設(shè)備[19]。實(shí)驗(yàn)所用2列動(dòng)車組模型與數(shù)值計(jì)算模型完全一致,編組同為8 輛,模型縮比均為1:31。根據(jù)流動(dòng)相似原理,動(dòng)模型實(shí)驗(yàn)中模擬雷諾數(shù)是重要的相似準(zhǔn)則,而當(dāng)實(shí)驗(yàn)雷諾數(shù)大于臨界雷諾數(shù)3.6×10 5(由實(shí)驗(yàn)測(cè)得)時(shí),氣動(dòng)特性就不再隨雷諾數(shù)變化而改變[19]。本次動(dòng)模型實(shí)驗(yàn)列車速度為250 km/h,特征長(zhǎng)度取模型車高0.119 m,在大氣壓為1×105Pa下,20℃時(shí)的空氣運(yùn)動(dòng)黏性系數(shù)為15.0×10?6m2/s,得出實(shí)驗(yàn)雷諾數(shù)為 5.5×105,大于臨界雷諾數(shù),說(shuō)明本次的實(shí)驗(yàn)結(jié)果滿足相似性要求。
兩動(dòng)車組在無(wú)風(fēng)下以250 km/h 速度交會(huì)時(shí),數(shù)值計(jì)算與動(dòng)模型實(shí)驗(yàn)中位于相同位置的測(cè)點(diǎn)壓力變化進(jìn)行對(duì)比。圖15所示為動(dòng)車組中部交會(huì)側(cè)測(cè)點(diǎn)(21號(hào)測(cè)點(diǎn))隨時(shí)間的壓力變化曲線對(duì)比。從圖15可以看出:通過(guò)數(shù)值計(jì)算與動(dòng)模型實(shí)驗(yàn)得到的車體表面壓力曲線變化規(guī)律基本一致,幅值相對(duì)誤差在 5%以內(nèi),說(shuō)明本文采用的數(shù)值計(jì)算方法可以較好地模擬動(dòng)車組交會(huì)時(shí)所引發(fā)的空氣動(dòng)力效應(yīng)問題。需注意的是:在用模型實(shí)驗(yàn)間接驗(yàn)證數(shù)值計(jì)算方法的可行性時(shí),只針對(duì)模型縮比影響進(jìn)行分析,對(duì)于列車模型編組差異帶來(lái)的影響將有待進(jìn)一步研究。
圖15 動(dòng)模型實(shí)驗(yàn)結(jié)果與計(jì)算結(jié)果比較Fig.15 Comparison between moving model experiment results andCalculation results
1)風(fēng)洞實(shí)驗(yàn)、 動(dòng)模型實(shí)驗(yàn)得到的結(jié)果分別與數(shù)值模擬進(jìn)行對(duì)比,所得到氣動(dòng)效應(yīng)變化規(guī)律基本一致,動(dòng)車組表面測(cè)點(diǎn)壓力幅值相對(duì)誤差在 5%以內(nèi),從而間接證明了本文采用的數(shù)值計(jì)算方法能夠較好地模擬動(dòng)車組橫風(fēng)下交會(huì)時(shí)所誘發(fā)的空氣動(dòng)力效應(yīng)問題。
2)動(dòng)車組在20 m/s橫風(fēng)下以250 km/h交會(huì)時(shí),車體表面最大正壓發(fā)生在車頭鼻尖附近,最大負(fù)壓及最大壓力峰峰值發(fā)生在車頭鼻尖偏交會(huì)側(cè)附近,且在車體頭、尾部不同位置測(cè)點(diǎn)壓力差別較大,頭車鼻尖處壓力比車身過(guò)渡處大4.00 kPa左右;車體頂部測(cè)點(diǎn)壓力始終為負(fù)值;車體中部處于同側(cè)的不同測(cè)點(diǎn)壓力差別較小,不同高度側(cè)點(diǎn)壓力幅值相差0.05 kPa左右,同一高度不同縱向測(cè)點(diǎn)壓力變化波形及幅值基本一致。
3)迎風(fēng)車所受橫向氣動(dòng)力及傾覆力矩在交會(huì)開始時(shí)先減小后增大,而在交會(huì)結(jié)束時(shí)先增大后減小,背風(fēng)車與之相反;與迎風(fēng)車相比,背風(fēng)車所受橫向氣動(dòng)力及傾覆力矩較大;與中間車和尾車相比,頭車所受橫向氣動(dòng)力及傾覆力矩較大;隨著橫風(fēng)風(fēng)速增大,車體所受橫向氣動(dòng)力及傾覆力矩峰值也迅速增大,嚴(yán)重威脅著動(dòng)車組的安全運(yùn)行。
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(編輯 陳燦華)
Aerodynamic effect of EMU passing by each other underCrosswind
LIU Feng,YAO Song,ZHANG Jie,ZHANG Na
(Key Laboratory of Traffic Safety on Track of Ministry of Education,School of Traffic & Transportation Engineering,Central South University,Changsha 410075,China)
Abstract:Based on unsteady N?S equation of three-dimensional andCompressible viscous fluid,the transient pressure on theCar surface,aerodynamic pressure and its moment were analyzed on theCondition that the EMU(electric multiple units)Consisting of8carriages interact with each other at the speed of 250 km/h under aCrosswind speed of 20 m/s.The results show that byContrasting the results of wind tunnel test and moving model experiment with numerical simulation using indirect verification method,theChange law of aerodynamic effect shows agreeable accordance with an error under 5%.When passing by each other underCrosswind,the pressure difference of measuring points on body and tail is obvious,the measuring points on the same side of middle part shows little difference,the waveform and amplitude of pressure variation on the measure points of different longitude directions with one height are the same generally,and the measurement point on the top of body presents negative pressure.The lateral force and overturning moment of the headCar are greater than those of the middle and the tail,and the later force and overturning moment of the leeward vehicle are greater than those of the upward one.With the increase ofCrosswind speed,the aerodynamic lateral force and overturning moment increase by the power law,which threatens the safe running of EMU greatly.
Key words:EMU(electric multiple units)?Crosswind? train-crossing? wind tunnel test? moving model experiment? aerodynamic effect
中圖分類號(hào):U271.91;U25
文獻(xiàn)標(biāo)志碼:A
文章編號(hào):1672?7207(2016)01?0307?07
DOI:10.11817/j.issn.1672-7207.2016.01.042
收稿日期:2015?01?10;修回日期:2015?03?25
基金項(xiàng)目(Foundation item):國(guó)家自然科學(xué)基金資助項(xiàng)目(11372360,U1134203,51205418);中南大學(xué)自由探索基金資助項(xiàng)目(2014zzts038);中國(guó)鐵路總公司科技研究開發(fā)計(jì)劃項(xiàng)目(2014T001-A);湖南省杰出青年基金資助項(xiàng)目(14JJ103)(Projects(11372360,U1134203,51205418)supported by the National Natural Science Foundation ofChina? Project(2014zzts038)supported by the Exploration and Innovation Funds for Graduate Students ofCentral South University? Project(2014T001-A)supported by Science and Technology Research and Development Program ofChina RailwayCorporation? Project(14JJ103)supported by Outstanding Youth Fund of Hunan Province)
通信作者:姚松,副教授,從事軌道交通安全研究;E-mail: song_yao@csu.edu.cn