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1、大連理工大學(xué)碩士學(xué)位論文摘要高效連鑄主要的發(fā)展方向,在拉速提高的條件下,必須優(yōu)化結(jié)晶器內(nèi)流場(chǎng)以適應(yīng)穩(wěn)定生產(chǎn)的需要,防止拉漏和鑄坯缺陷的產(chǎn)生。本文將PIV(粒子圖像測(cè)速)技術(shù)應(yīng)用于連鑄結(jié)晶器內(nèi)流場(chǎng)研究,介紹了PIV測(cè)試流場(chǎng)的基本原理以及相應(yīng)的硬件系統(tǒng)(激光器、CCD相機(jī)等)和軟件系統(tǒng)(圖像采集系統(tǒng)、圖像處理系統(tǒng)),尋求到適宜大板坯連鑄模型的示蹤粒子,并總結(jié)出PIV系統(tǒng)用于大板坯連鑄模擬的軟件設(shè)置參數(shù),對(duì)結(jié)晶器內(nèi)流場(chǎng)實(shí)現(xiàn)可視化。針對(duì)1650mm×220mm大板坯連鑄,設(shè)計(jì)了PIV物理模擬系統(tǒng),包括結(jié)晶器模型、水循環(huán)系統(tǒng)、水口
2、設(shè)計(jì)、交流片光源系統(tǒng)。在不同的水口出口角度、水口浸入深度、鑄造速度,不同水口內(nèi)徑以及凹井狀況不同的條件下進(jìn)行了定量分析。結(jié)果表明:(1)在入射流的上部和下部分別存在兩個(gè)大的漩渦,下部的更大一些,這兩個(gè)漩渦的狀態(tài)直接影響連鑄坯的質(zhì)量:(2)出水口角度和浸入深度是影響流場(chǎng)流動(dòng)模式的重要因素,就所模擬的大板坯而言,水口浸入深度選擇在i30mm左右的是適宜的,出水口角度越大,流股的沖擊深度越深;(3)鑄造速度越大,流股對(duì)結(jié)晶器窄面的沖擊點(diǎn)也越高,此外,較高的鑄速會(huì)引起彎月面的劇烈波動(dòng),這將會(huì)引起各種缺陷;(4)水口內(nèi)徑和出水口面
3、積大小影響流場(chǎng)速度,凹井狀況對(duì)流場(chǎng)也存在一定的影響。關(guān)鍵詞:PlV;物理模擬;鋼連鑄;流場(chǎng)張文肖:板坯連鑄結(jié)晶器內(nèi)熔體流動(dòng)的PW分析PIVAnalysisonFlowintheMoldduringContinuousCastingofSteelSlabAbstractHigh-efficiencycontinuouscastinghasbecomethemaindevelopmentdirectionofthecontinuouscasting.Fluidflowinthemoldmustbeoptimizedinord
4、ertoimprovetheinternalandsurfacequalityofthecastandavoidsteelleakingwhileincreasingthecastingspeed.Inthispaper,PIV(ParticleImageVelocimetry)isusedtostudythefluidflowphenomenaincontinuouscastingofsteel.研豫paperdescribesflmdamentalprincipleofPⅣaswellasitshardware(1a
5、ser,CCDetc.)andsoftwaresystem(imagegatheringsystem,imageprocessingsystem).Suitableseedingparticleandsoftwaresettingparametersarefoundfortheslabphysicalsimulationexperiment.Flowvisualizationinthemoldiswellachieved.Physicalmodelsystemforcontinuouscastingofslabwitht
6、hesizeof1650mmx220mmiSdesigned,includingmoldmodel,watercirculationsystem,AC(alternatingcurrent)sheetlightsystem.nleinfluenceofnozzleangle,nozzlediameter,immerseddepthofnozzle,pitstructl:n'eofnozzleandthecastingspeedontheflowbehaviorareinvestigatedquantitatively.T
7、heresultshaveshownthat:(1)Therearetwolargere-circulationsaboveandbelowoffluidjetinthemoldseparately,andthebelowvortexislargerthantheaboveone.Theslabqualityiscloselyrelatedwiththesetwovortexes.(2)Theangleandimmerseddepthofnozzlearetwoimportantfactorswhichinfluence
8、theflowinthemold.Asforthesimulatingmodel,thesuitableimmerseddepthischosenabout130mm.Thebiggertheangleis,thelowertheimpactingpointOilthenalTOWface.(3)Thehighert