波样耗散结构的空间构造及形成过程

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1、西南交通大学硕士学位论文波样耗散结构的空间构造及形成过程姓名：贾琛霞申请学位级别：硕士专业：供热、供燃气、通风及空调工程指导教师：敬成君20090301西南交通大学硕士研究生学位论文第1I页作用时数值计算的结果。由单独浮力和单独离心力作用下的融液表面等温线分布均表现为平凡的同心圆，但是通过对比分析构成它们的主要基本模式，发现两种情况下基本模式并不相同，最后，通过比较这两种情况下的主要基本模式与原始温度场的基本模式得出结论：对于本文所研究的波样耗散结构起主要作用的是浮力不稳定性。本文结果丰富了人们对波样耗散结构的认识。希望为进一步分析波样耗散结构这一特殊流动现象做好理论铺垫，并希望对制

2、备单晶的生产工艺提供理论指导。关键词：波样流动；耗散结构：正交分解；数值模拟AbstractThephenomenaofwavedissipativestructuresappearintheCzochralski(Cz、crystalgrowth·Asacomplicatedmeltflow,theobservedwavedissipativestructuresarecausedbydifferenttypesofinstabilitysuchasbuoyancy-indueedinstability．Marangoniinstabilityandrotationinstabil

3、ity．Thesinglecrystalwith1argedi锄eterandhighqualityisalwaysmanufacturers’target．Thewavedissipativestructuresappearonthefreesurfaceofmeltingrowinglarge—scalesinglecrystals，sostudVforproducinglarge—scalesinglecrystalisveryimportant．Sincethewavedissipativestructurebeingdiscovered，manyscholarsdidalo

4、tofstudiesonthephenomena，butafewofstudiesisonwhatthesmallcellswhichcomposingthemacrostructureareandhowthesmallcellsformthemacrostnlctm．e．Furthermore，whatistheinstabilitywhichdogreatcontributiontothesystemstability?InthispapermeltthermalconvectionsinCzockralski(cz)crystalgrowthsystemwereinvestig

5、atedandfamousdissipativestructures．wavepatternswithdi髓remtfoldswereobtainednumerically．ThebasicmodesofthewavedissipativestructureswereextractedoutbyProperOrthogonalDecomposition(POD)．Thebasicmodesthatformwavedissipativestructuresandthedynamicformationprocess．andthemajorinstabilityhavebeenanalys

6、ed．Itisfoundthat：(1)．Themainbasicmodesofthewavedissipativestructuresveryregularily,themacroscopicwavepatternstakeformofalotofsmallbasisVortices．Themainbasicmodesofthetwo．foldswavedissipativestructuresappeatsinpair,and4smallvorticesregularlyincreasedintheazimothialdirection．Asthesame，thethree-fo

7、ldswavedissipativestructuresappearinthree，andintheazimothialdirection6smallvorticesregularlyincreased．Intheradial．thewavepatternswithtwoandthree-foldsallincreasedfrom1storeybtomore．(2)．Theoriginaltemperaturefiledofwavedissipatives