基于细观结构的阴极炭块钠膨胀应力数值分析及实验验证
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摘要
在细观层面上将阴极炭块视为由骨料和粘结剂组成的二相复合材料,应用蒙特卡洛方法建立二维随机骨料模型,使用ANSYS有限元软件的热分析模块求解钠膨胀应力模型,对不同形状、级配、含量的骨料模型的钠膨胀应力进行了数值模拟。结果表明:阴极炭块细观结构的非均匀性造成钠膨胀应力的不均匀分布,特别是拉应力集中导致阴极炭块破损;级配0.003~0.015 m炭骨料钠膨胀量最小,级配0.003~0.006 m炭骨料钠膨胀量最大,骨料含量80%钠膨胀量最小,骨料含量60%钠膨胀量最大。该模型的数值模拟结果与实验结果基本相符,表明该模型描述的钠膨胀和应力分布是合理和有效的,可以作为研究阴极炭块钠膨胀应力性能的一种有效辅助手段。
The cathode carbon block was regarded as a two-phase composite material composed of aggregates and binder in mesoscopic scale, for description of which, a two-dimensional random aggregate model was established by Monte Carlo method. Then the numerical simulation of sodium expansion induced stress of aggregate model was established by the thermal analysis module of ANSYS finite element software in consideration of different shapes, gradations and contents of the aggregate. The results show that the nonuniformity of the meso-structure in the cathode carbon block causes the nonuniform distribution of the stress induced by the sodium expansion. Particularly, the presence of the tensile stress can lead to the damage of the cathode carbon block. The sodium expansion of the carbon blocks with the carbon aggregate within the gradation of 0.003-0.015 m is the lowest, while those within the gradation of0.003-0.006 m is the highest. The sodium expansion of the carbon block with 80% carbon aggregate is the lowest, while that with 60% carbon aggregate is the highest. The numerical simulation results are in accordance with the experimental results,which means that this model can reasonably and effectively de-scribe the sodium expansion and stress distribution of the carbon block. Thus it can be used as an effective auxiliary way to study phenomena related with the sodium expansion induced stress.
The cathode carbon block was regarded as a two-phase composite material composed of aggregates and binder in mesoscopic scale, for description of which, a two-dimensional random aggregate model was established by Monte Carlo method. Then the numerical simulation of sodium expansion induced stress of aggregate model was established by the thermal analysis module of ANSYS finite element software in consideration of different shapes, gradations and contents of the aggregate. The results show that the nonuniformity of the meso-structure in the cathode carbon block causes the nonuniform distribution of the stress induced by the sodium expansion. Particularly, the presence of the tensile stress can lead to the damage of the cathode carbon block. The sodium expansion of the carbon blocks with the carbon aggregate within the gradation of 0.003-0.015 m is the lowest, while those within the gradation of0.003-0.006 m is the highest. The sodium expansion of the carbon block with 80% carbon aggregate is the lowest, while that with 60% carbon aggregate is the highest. The numerical simulation results are in accordance with the experimental results,which means that this model can reasonably and effectively de-scribe the sodium expansion and stress distribution of the carbon block. Thus it can be used as an effective auxiliary way to study phenomena related with the sodium expansion induced stress.
引文
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[4]Solheim A,Moxnes B P,Vamraak K,et al.Energy recovery and amperage increase in aluminium cells by active cooling of the anode yokes[A].Beame G.Light Metals 2009[C].Warrendale:TMS,2009:1091
[5]Lai Y Q,Xu J,Lv X J,et al.Effect of inorganic particles on properties of modified pitches and pitch based Ti B2/C composite cathodes for aluminium electrolysis[J].J.Central South Univ.(Sci.Technol.),2012,43:2029(赖延清,胥建,吕晓军等.铝电解Ti B2/C复合阴极用煤沥青的无机改性[J].中南大学学报(自然科学版),2012,43:2029)
[6]Liu Q S,Xue J L,Zhu J,et al.Effects of additives on the sodium penetration and expansion of carbon-based cathodes during aluminum electrolysis[J].J.Univ.Sci.Technol.Beijing,2008,30:403(刘庆生,薛济来,朱骏等.添加剂对铝电解炭基阴极钠渗透膨胀过程的影响[J].北京科技大学学报,2008,30:403)
[7]Stewart M G,Wang X M,Nguyen M N.Climate change impact and risks of concrete infrastructure deterioration[J].Eng.Struct.,2011,33:1326
[8]Zhang H H,Zhang H L,Cui X F,et al.Impact of cathode carbon block material on the thermal-electric field in aluminum reduction cell[J].Nonferrous Met.Eng.Res.,2011,23(2):13(张翮辉,张红亮,崔喜风等.阴极炭块材料对铝电解槽电热场影响的研究[J].有色冶金设计与研究,2011,32(2):13)
[9]Xu Z L.Elasticity[M].4th ed.Beijing:Higher Education Press,2011(徐芝纶.弹性力学[M].4版.北京:高等教育出版社,2011)
[10]Song X G,Yang Z C.A new method to simulate round concrete aggregate generation[J].Eng.Mech.,2010,27(1):154(宋晓刚,杨智春.一种新的混凝土圆形骨料投放数值模拟方法[J].工程力学,2010,27(1):154)
[11]Liu Q S,He W,Zeng F J,et al.Damage properties of carbon cathodes under different aluminium electrolysis time[J].J.Mater.Eng.,2013,(7):92(刘庆生,何文,曾芳金等.不同铝电解时间下阴极炭块的损伤特性研究[J].材料工程,2013,(7):92)
[12]Zolochevsky A,Hop J G,Servant G,et al.Creep and sodium expansion in a semigraphitic cathode carbon[A].Kvande H.Light Metals 2003[C].San Francisco,CA:TMS,2003:595
[13]Yan L,Yang C H,Wang C.Influence of coarse aggregates'shape index and gradation in self-compacting concrete's rheological behavior and working performance[J].Concrete,2011,(1):75(严琳,杨长辉,王冲.粗骨料颗粒形状指数、级配对自密实混凝土工作性能的影响[J].混凝土,2011,(1):75)
[14]Chauke L,Garbers-Craig A M.Reactivity between carbon cathode materials and electrolyte based on industrial and laboratory data[J].Carbon,2013,58:40
[15]Coulombe M A,Lebeuf M,Chartrand P,et al.Carburation phenomenons at the cathode block/metal interface[A].Johnson J A.Light Metals 2010[C].Warrendale,PA,USA:TMS,2010:811