发泡模具射料充填过程的数值模拟
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摘要
干砂负压消失模铸造技术(简称LFC)中模样是消失模铸造成败的关键,而泡沫珠粒的充填是获得优质泡沫模样的关键工序之一。泡沫珠粒在模具中充填不均或不密实会使模样出现残缺不全或融合不充分等缺陷,影响产品的表面质量。因此利用计算机对泡沫珠粒射料充填过程的流动场进行数值模拟,定量地了解射料过程的影响因素,有利于优化射料工艺、提高效率和减少废品。
本文系统全面地推导出密相可压气固两相流的封闭的控制方程,并讨论了方程组中各相的物理意义,建立了适用于射料充填过程的欧拉-欧拉双流体数学模型,为数值模拟奠定了坚实的理论基础。
采用计算流体分析软件Fluent 对发泡模具射料充填过程进行数值模拟,在Fluent 中使用SIMPLE 算法和隐式分离数值求解方法计算已推导的控制方程组的解,计算出不同时刻的各个控制体单元内的泡沫珠粒的体积百分数,得到了射料充填过程中泡沫珠粒的流动状态。
通过对多种情况下的射料充填过程进行物理模拟,考察不同射料方式和挡块位置的影响,用数码摄像机记录射料过程,总结了射料充填过程的一些特点和规律。试验结果与数值模拟结果对比表明,模拟结果中的泡沫珠粒的流动趋势与实际情况基本上是一致的,使用该数学模型对射料充填过程进行数值模拟是一种行之有效的方法。
In lost foam casting(LFC),the foam pattern is the key qualification, and the filling process is one of the crucial processes to ensure the high quality of the foam pattern. Filling without uniformity and denseness will cause various defects and affect the quality of the surface. The influential factors of filling process are realized .And optimizing filling process, enhancing efficiency, decreasing waster and so on are obtained by the numerical simulation of filling process using computer .
In this paper the governing equations of the dense compressible gas-solid two-phase flow are established, and the physical signification of each one in the equations is discussed. The filling process is solved by Euler-Euler two fluid model .It is crucial for the simulation.
The filling process is simulated by Fluent, an analysis software of the computation fluid dynamics. In the simulation, SIMPLE and implicit segregated methods are used. The volume of foam bead in every governing unit at different time is calculated, and the trend of foam bead flow is obtained.
The filling process of various different conditions are simulated, considering different shooting methods and the position of baffles, and recorded by digital vidicon. The characteristics and the rules of the process are summarized. By contrasting the result of numerical simulation with the one of examination, it is found that the fluid trend of foam bead in the numerical simulation is accordant to the actual process. So the numerical simulation of filling process by applying this model is an effective method.
本文系统全面地推导出密相可压气固两相流的封闭的控制方程,并讨论了方程组中各相的物理意义,建立了适用于射料充填过程的欧拉-欧拉双流体数学模型,为数值模拟奠定了坚实的理论基础。
采用计算流体分析软件Fluent 对发泡模具射料充填过程进行数值模拟,在Fluent 中使用SIMPLE 算法和隐式分离数值求解方法计算已推导的控制方程组的解,计算出不同时刻的各个控制体单元内的泡沫珠粒的体积百分数,得到了射料充填过程中泡沫珠粒的流动状态。
通过对多种情况下的射料充填过程进行物理模拟,考察不同射料方式和挡块位置的影响,用数码摄像机记录射料过程,总结了射料充填过程的一些特点和规律。试验结果与数值模拟结果对比表明,模拟结果中的泡沫珠粒的流动趋势与实际情况基本上是一致的,使用该数学模型对射料充填过程进行数值模拟是一种行之有效的方法。
In lost foam casting(LFC),the foam pattern is the key qualification, and the filling process is one of the crucial processes to ensure the high quality of the foam pattern. Filling without uniformity and denseness will cause various defects and affect the quality of the surface. The influential factors of filling process are realized .And optimizing filling process, enhancing efficiency, decreasing waster and so on are obtained by the numerical simulation of filling process using computer .
In this paper the governing equations of the dense compressible gas-solid two-phase flow are established, and the physical signification of each one in the equations is discussed. The filling process is solved by Euler-Euler two fluid model .It is crucial for the simulation.
The filling process is simulated by Fluent, an analysis software of the computation fluid dynamics. In the simulation, SIMPLE and implicit segregated methods are used. The volume of foam bead in every governing unit at different time is calculated, and the trend of foam bead flow is obtained.
The filling process of various different conditions are simulated, considering different shooting methods and the position of baffles, and recorded by digital vidicon. The characteristics and the rules of the process are summarized. By contrasting the result of numerical simulation with the one of examination, it is found that the fluid trend of foam bead in the numerical simulation is accordant to the actual process. So the numerical simulation of filling process by applying this model is an effective method.
引文
[1] 黄乃瑜, 罗吉荣. 面向21 世纪的消失模铸造技术. 特种铸造及有色合金,1998(4):37~40
[2] 黄乃瑜,叶升平,樊自田.消失模铸造原理及质量控制.武汉:华中科技大学出版社,2004
[3] 胡国良.消失模铸造用共聚物泡沫模样的成型及控制技术.[硕士学位论文],武汉:华中科技大学材料学院,2002
[4] 王文琪.两相流动.北京:水利电力出版社,1989
[5] Hiroyasu Makino,Yasuhiro Maeda,Hiroyuki Nomura.Force analysis in air-flow press moulding using the distinct element method[J].Int.J.Cast Metal Res,1997,10:171~175
[6] Pelzer M,Meiser L,Sahm Pro. Simulation of the Core shooting Process [R].CIATF Technical Forum 99
[7] 陈代海,崔怡,王海,吴浚郊.射砂过程气砂两相运动的研究.中国铸造装备与技术,2001(4):12~13
[8] 王涛,崔怡,陈代海,李文珍.射砂紧实过程的试验研究.中国铸造装备与技术,2001(2):9~11
[9] 崔怡, 李文珍, 吴浚郊, 张涛. 射砂紧实机理的研究. 中国铸造装备与技术,2001(1):17~19
[10] 崔怡,李文珍,吴浚郊.射砂过程初始条件的试验研究.中国铸造装备与技术,2000(5):11~13
[11] 崔怡,李文珍,吴浚郊.射砂过程的数值模拟.特种铸造及有色合金,2001(2):34~36
[12] 陈代海,崔怡,吴浚郊.芯盒设计对射砂过程的影响.铸造,2001(7),342~345
[13] 崔怡,李文珍, 吴浚郊. 利用两相流模型模拟射砂过程的进展.铸造技术, 2000(6):8~10
[14] 崔怡, 李文珍, 吴浚郊. 芯盒结构对射砂过程的影响. 特种铸造及有色合金,2000(3):4~6
[15] 崔怡,李文珍,吴浚郊,张涛.冷芯盒射砂工艺参数的研究.铸造,2000(9):527~532
[16] 李宏亮,崔怡,吴浚郊.射砂过程数值模拟的技术现状.铸造,2002(11):737~740
[17] Aubery Miller,Dimitri Gidaspow. Dense,Verticle Gas-solid Flow in a Pipe[J].AIChE,1992,38(11):1801~1815
[18] B G M van Wachem,J C Schouten,C M van den Bleek.Comparative Analysis of CFD Models of Dense Gas Solid Systems. AIChE,2001,47(5):1035~1051
[19] 美国Arena-Flow 公司的介绍光盘[CD].堪萨斯城:美国铸造博览会,2002,5
[20] 曾卓雄.密相可压气固两相湍流流动的理论分析及其数值模拟.[博士学位论文],西安:西安交通大学能源学院,2001
[21] C T Crow. Review-Numerical models for dilute gas-particle flows [J]. ASME J Fluids Eng,1982,104:297~303
[22] 连桂森.多相流动基础.杭州:浙江大学出版社,1989
[23] 岑可法,樊建人.工程气固多项流动的理论及计算.杭州:浙江大学出版社,1990
[24] M A Rizk,S E Eloghobshi. A two-equation turbulence modle for dispersed dilute confined two-phase flows [J]. Int J Multiphase Flow,1989,15(1:) 119~133
[25] 周力行.湍流两相流动与燃烧的数值模拟[M].北京:清华大学出版社,1991
[26] J L Sinclair,R Jackson.Gas-particle flow in a vertical pipe with particle-particle interaction[J].AIChE J,1989,35(9):1473~1486
[27] 刘大有.两相流体动力学[M].北京:高等教育出版社,1993
[28] R C Givler.An interpretation for solid-phase pressure in slow fluid particle flow[J].Int J Multiphase Flow,1987,13(5):717~722
[29] E J Bolio,J A Yasuna, J L Sinclair. Dilute turbulent gas-solid flow in riser with particle-particle interaction [J]. AICHE J,1995,41(6):1375~1388
[30] 施学贵,徐旭常,冯俊凯.颗粒在湍流中的运动受力分析[J].工程热物理学报,1989,10(3):320~325
[31] S L Soo. Particulate and Continuum Multiphase Fluid Dynamics[M]. Hemisphere publishing Corporation,1989
[32] D J Carlson.Particle drag and heat transfer in recoket nozzles[J].AIAA J,1964,2(11)
[33] Samuelsberg,B H Hjertager. An Experimental and numerical study of flow patterns in a circulating fluidized bed reactor[J].Int J Multiphase Flow,1996,22(3):575~591
[34] J Ding,D Gidaspow. A bulbing fluidization model using kinetic theory of granular flow[J].AIChE J,1990,36(4):523~538
[35] D Gidaspow. Multiphase flow and fluidization: continnum and kinetic theory descriptions[M].Boston:Academic press,1994
[36] 郭烈锦.两相流与多相流动力学.西安:西安交通大学出版社
[37] 李勇,刘志友,安亦然.介绍计算流体力学通用软件—Fluent.水动力学研究与进展,2001(6):254~258
[38] 韩占忠,王敬,兰小平.Fluent 流体工程仿真计算实例与应用.北京:北京理工大学出版社
[39] Hui. Boundary conditions for high shear grain flows[J], J Fluid Mech,1984,145(223)
[40] S B Savage. Granular flows at high shear rates, In theory of dispersed multiphase flow[M].Academic Press,1983:191~226
[2] 黄乃瑜,叶升平,樊自田.消失模铸造原理及质量控制.武汉:华中科技大学出版社,2004
[3] 胡国良.消失模铸造用共聚物泡沫模样的成型及控制技术.[硕士学位论文],武汉:华中科技大学材料学院,2002
[4] 王文琪.两相流动.北京:水利电力出版社,1989
[5] Hiroyasu Makino,Yasuhiro Maeda,Hiroyuki Nomura.Force analysis in air-flow press moulding using the distinct element method[J].Int.J.Cast Metal Res,1997,10:171~175
[6] Pelzer M,Meiser L,Sahm Pro. Simulation of the Core shooting Process [R].CIATF Technical Forum 99
[7] 陈代海,崔怡,王海,吴浚郊.射砂过程气砂两相运动的研究.中国铸造装备与技术,2001(4):12~13
[8] 王涛,崔怡,陈代海,李文珍.射砂紧实过程的试验研究.中国铸造装备与技术,2001(2):9~11
[9] 崔怡, 李文珍, 吴浚郊, 张涛. 射砂紧实机理的研究. 中国铸造装备与技术,2001(1):17~19
[10] 崔怡,李文珍,吴浚郊.射砂过程初始条件的试验研究.中国铸造装备与技术,2000(5):11~13
[11] 崔怡,李文珍,吴浚郊.射砂过程的数值模拟.特种铸造及有色合金,2001(2):34~36
[12] 陈代海,崔怡,吴浚郊.芯盒设计对射砂过程的影响.铸造,2001(7),342~345
[13] 崔怡,李文珍, 吴浚郊. 利用两相流模型模拟射砂过程的进展.铸造技术, 2000(6):8~10
[14] 崔怡, 李文珍, 吴浚郊. 芯盒结构对射砂过程的影响. 特种铸造及有色合金,2000(3):4~6
[15] 崔怡,李文珍,吴浚郊,张涛.冷芯盒射砂工艺参数的研究.铸造,2000(9):527~532
[16] 李宏亮,崔怡,吴浚郊.射砂过程数值模拟的技术现状.铸造,2002(11):737~740
[17] Aubery Miller,Dimitri Gidaspow. Dense,Verticle Gas-solid Flow in a Pipe[J].AIChE,1992,38(11):1801~1815
[18] B G M van Wachem,J C Schouten,C M van den Bleek.Comparative Analysis of CFD Models of Dense Gas Solid Systems. AIChE,2001,47(5):1035~1051
[19] 美国Arena-Flow 公司的介绍光盘[CD].堪萨斯城:美国铸造博览会,2002,5
[20] 曾卓雄.密相可压气固两相湍流流动的理论分析及其数值模拟.[博士学位论文],西安:西安交通大学能源学院,2001
[21] C T Crow. Review-Numerical models for dilute gas-particle flows [J]. ASME J Fluids Eng,1982,104:297~303
[22] 连桂森.多相流动基础.杭州:浙江大学出版社,1989
[23] 岑可法,樊建人.工程气固多项流动的理论及计算.杭州:浙江大学出版社,1990
[24] M A Rizk,S E Eloghobshi. A two-equation turbulence modle for dispersed dilute confined two-phase flows [J]. Int J Multiphase Flow,1989,15(1:) 119~133
[25] 周力行.湍流两相流动与燃烧的数值模拟[M].北京:清华大学出版社,1991
[26] J L Sinclair,R Jackson.Gas-particle flow in a vertical pipe with particle-particle interaction[J].AIChE J,1989,35(9):1473~1486
[27] 刘大有.两相流体动力学[M].北京:高等教育出版社,1993
[28] R C Givler.An interpretation for solid-phase pressure in slow fluid particle flow[J].Int J Multiphase Flow,1987,13(5):717~722
[29] E J Bolio,J A Yasuna, J L Sinclair. Dilute turbulent gas-solid flow in riser with particle-particle interaction [J]. AICHE J,1995,41(6):1375~1388
[30] 施学贵,徐旭常,冯俊凯.颗粒在湍流中的运动受力分析[J].工程热物理学报,1989,10(3):320~325
[31] S L Soo. Particulate and Continuum Multiphase Fluid Dynamics[M]. Hemisphere publishing Corporation,1989
[32] D J Carlson.Particle drag and heat transfer in recoket nozzles[J].AIAA J,1964,2(11)
[33] Samuelsberg,B H Hjertager. An Experimental and numerical study of flow patterns in a circulating fluidized bed reactor[J].Int J Multiphase Flow,1996,22(3):575~591
[34] J Ding,D Gidaspow. A bulbing fluidization model using kinetic theory of granular flow[J].AIChE J,1990,36(4):523~538
[35] D Gidaspow. Multiphase flow and fluidization: continnum and kinetic theory descriptions[M].Boston:Academic press,1994
[36] 郭烈锦.两相流与多相流动力学.西安:西安交通大学出版社
[37] 李勇,刘志友,安亦然.介绍计算流体力学通用软件—Fluent.水动力学研究与进展,2001(6):254~258
[38] 韩占忠,王敬,兰小平.Fluent 流体工程仿真计算实例与应用.北京:北京理工大学出版社
[39] Hui. Boundary conditions for high shear grain flows[J], J Fluid Mech,1984,145(223)
[40] S B Savage. Granular flows at high shear rates, In theory of dispersed multiphase flow[M].Academic Press,1983:191~226