基于CFD的气动喷砂机理与喷砂流场特性研究
|
摘要
气动喷砂是以压缩空气为动力,磨料通过喷嘴加速后,喷射到零件表面,可用于表面强化、表面清洗等工作,广泛地应用于机械、石油、化工、汽车、船舶等行业。
喷嘴是气动喷砂系统中的关键部件之一,其作用是改变气固两相流体的运动和动力特性,对喷砂系统的清理效率影响最大。基于CFD技术,研究气动喷砂机理,对喷嘴内气固两相流动参数之间及其与变截面喷嘴几何参数之间的关系进行分析和研究,为高效喷嘴的设计提供依据;研究气动喷砂流场,对喷嘴出流时气固两相流体的自由喷流颗粒流场进行分析,并对气动喷砂作用表面的冲蚀特性进行研究,得出气固两相流动参数与几何参数对气动喷砂流场特性的影响关系,为气动喷砂系统高效工作提供理论指导;因此,开展气动喷砂机理与喷砂流场特性研究具有重要的实际意义。
在气动喷砂机理研究方面,对喷嘴内气固两相流采用遵循欧拉—拉格朗日方法的离散相模型。应用Fluent软件,采用标准的k-ε模型对喷嘴内气体流场进行仿真计算,获得了气体的压力场和速度场的分布;通过对固体颗粒在气体流场中的仿真模拟,得到了固体颗粒的运动轨迹、速度和动力特性的变化规律。研究表明:固体颗粒粒径越小,受
气体影响越大;不同粒径固体颗粒通过喷嘴后获得的最大总动量不同,与此对应的喷嘴收缩角也不同,并且粒径越大,固体颗粒获得最大总动量对应的喷嘴收缩角越小。在气动喷砂流场研究方面,应用Spalart-Allmaras模型对气体自由喷流流场仿真,获得喷嘴出口欠膨胀超声速喷流产生的链状流场结构。对平板的冲击流场进行仿真,观察到板激波,驻泡等现象。当气体流场中加入固体颗粒时,得到散射状的颗粒流场结构。比较不同粒径固体颗粒对同一位置的平板的平均冲击动量发现:粒径为0.4mm~0.8mm固体颗粒对平板中心的冲击动量值较大,冲击效果较好。除了由于喷嘴与平板很近时(小于10mm),颗粒的积聚影响了冲刷效果以外,固体颗粒对平板中心的冲蚀程度随着平板与喷嘴出口间距离的增大而减小。
The pneumatic sand blasting takes compressed air as motive force, and the abrasive spraysthe part surfaces after the acceleration of the nozzle, it is available in surface strengthen andsurface cleaning etc, it should be extensively applied in machinery, petroleum, chemicalindustry, automobile and shipping etc.
The nozzle is one of the critical parts in the pneumatic sand blasting system, and its effectis to change the motion and the motive force property of the gas-solid-two-phase fluid, itgreatly influences the cleaning efficiency. To study pneumatic sand blasting mechanism basedon the CFD technology, analyzing and studying the relation of gas-solid-two-phase fluidparameters and as well as geometry parameters of section changed nozzle, provides the basisfor the design of the high efficiency nozzle. Studying the pneumatic sand blasting flow field,we can find the influence relation of gas-solid-two-phase fluid parameters and geometryparameters to pneumatic sand blasting flow field property by analyzing free jet particles fieldof gas-solid-two-phase fluid and studying impinging corrosion property of effect surface, itprovides theoretical instruction of high efficiency work for the pneumatic sand blasting system.Therefore, the study on the pneumatic sand blasting mechanism and sand blasting flow fieldproperty has important practical significance.
The Discrete Phase Model which follows the Euler-Lagrange approach is used to simulategas-solid-two-phase fluid in the nozzle at the aspect of pneumatic sand blasting mechanismresearch. Applying Fluent software, the distribution of the pressure field and the velocity fieldof gas are gained by adopting standard k-ε model to simulate gas flow field in the nozzle;thekinematic trajectory, velocity and dynamic property are gained by simulating solid particlesmovement in the gas flow field. The research indicates: the influence of the gas is more evidentwhen the particles diameter becomes smaller;the solid particles of different diametercorrespond to different maximal momentum in the outlet and the nozzle diminishing-angle, andwhen the particles gain maximal momentum, the nozzle diminishing-angle becomes smallalong with particles diameter becoming big.
The Spalart-Allmaras Model is Applied to simulate free jet and impinging jet on flat, thechain form flow field configuration of supersonic underexpanded jet, the plate shock andstagnation bubble of impinging jet in the nozzle outlet are gained;when solid particles areadded in the gas flow filed, its flow field structure is scattering form;we find that the particlediameter between 0.3mm and 0.8mm has great impinging effect in the center of the flat bycomparing the mean impinging momentum of different diameter particles colliding samelocation flat. The level of impinging erosion decreases along with the increasing of the distanceof the nozzle and plate, except the plate greatly close to the nozzle when the accumulation ofparticles affects the efficiency of impinging erosion.
喷嘴是气动喷砂系统中的关键部件之一,其作用是改变气固两相流体的运动和动力特性,对喷砂系统的清理效率影响最大。基于CFD技术,研究气动喷砂机理,对喷嘴内气固两相流动参数之间及其与变截面喷嘴几何参数之间的关系进行分析和研究,为高效喷嘴的设计提供依据;研究气动喷砂流场,对喷嘴出流时气固两相流体的自由喷流颗粒流场进行分析,并对气动喷砂作用表面的冲蚀特性进行研究,得出气固两相流动参数与几何参数对气动喷砂流场特性的影响关系,为气动喷砂系统高效工作提供理论指导;因此,开展气动喷砂机理与喷砂流场特性研究具有重要的实际意义。
在气动喷砂机理研究方面,对喷嘴内气固两相流采用遵循欧拉—拉格朗日方法的离散相模型。应用Fluent软件,采用标准的k-ε模型对喷嘴内气体流场进行仿真计算,获得了气体的压力场和速度场的分布;通过对固体颗粒在气体流场中的仿真模拟,得到了固体颗粒的运动轨迹、速度和动力特性的变化规律。研究表明:固体颗粒粒径越小,受
气体影响越大;不同粒径固体颗粒通过喷嘴后获得的最大总动量不同,与此对应的喷嘴收缩角也不同,并且粒径越大,固体颗粒获得最大总动量对应的喷嘴收缩角越小。在气动喷砂流场研究方面,应用Spalart-Allmaras模型对气体自由喷流流场仿真,获得喷嘴出口欠膨胀超声速喷流产生的链状流场结构。对平板的冲击流场进行仿真,观察到板激波,驻泡等现象。当气体流场中加入固体颗粒时,得到散射状的颗粒流场结构。比较不同粒径固体颗粒对同一位置的平板的平均冲击动量发现:粒径为0.4mm~0.8mm固体颗粒对平板中心的冲击动量值较大,冲击效果较好。除了由于喷嘴与平板很近时(小于10mm),颗粒的积聚影响了冲刷效果以外,固体颗粒对平板中心的冲蚀程度随着平板与喷嘴出口间距离的增大而减小。
The pneumatic sand blasting takes compressed air as motive force, and the abrasive spraysthe part surfaces after the acceleration of the nozzle, it is available in surface strengthen andsurface cleaning etc, it should be extensively applied in machinery, petroleum, chemicalindustry, automobile and shipping etc.
The nozzle is one of the critical parts in the pneumatic sand blasting system, and its effectis to change the motion and the motive force property of the gas-solid-two-phase fluid, itgreatly influences the cleaning efficiency. To study pneumatic sand blasting mechanism basedon the CFD technology, analyzing and studying the relation of gas-solid-two-phase fluidparameters and as well as geometry parameters of section changed nozzle, provides the basisfor the design of the high efficiency nozzle. Studying the pneumatic sand blasting flow field,we can find the influence relation of gas-solid-two-phase fluid parameters and geometryparameters to pneumatic sand blasting flow field property by analyzing free jet particles fieldof gas-solid-two-phase fluid and studying impinging corrosion property of effect surface, itprovides theoretical instruction of high efficiency work for the pneumatic sand blasting system.Therefore, the study on the pneumatic sand blasting mechanism and sand blasting flow fieldproperty has important practical significance.
The Discrete Phase Model which follows the Euler-Lagrange approach is used to simulategas-solid-two-phase fluid in the nozzle at the aspect of pneumatic sand blasting mechanismresearch. Applying Fluent software, the distribution of the pressure field and the velocity fieldof gas are gained by adopting standard k-ε model to simulate gas flow field in the nozzle;thekinematic trajectory, velocity and dynamic property are gained by simulating solid particlesmovement in the gas flow field. The research indicates: the influence of the gas is more evidentwhen the particles diameter becomes smaller;the solid particles of different diametercorrespond to different maximal momentum in the outlet and the nozzle diminishing-angle, andwhen the particles gain maximal momentum, the nozzle diminishing-angle becomes smallalong with particles diameter becoming big.
The Spalart-Allmaras Model is Applied to simulate free jet and impinging jet on flat, thechain form flow field configuration of supersonic underexpanded jet, the plate shock andstagnation bubble of impinging jet in the nozzle outlet are gained;when solid particles areadded in the gas flow filed, its flow field structure is scattering form;we find that the particlediameter between 0.3mm and 0.8mm has great impinging effect in the center of the flat bycomparing the mean impinging momentum of different diameter particles colliding samelocation flat. The level of impinging erosion decreases along with the increasing of the distanceof the nozzle and plate, except the plate greatly close to the nozzle when the accumulation ofparticles affects the efficiency of impinging erosion.
引文
[1] 李国英主编.表面工程手册[M].北京:中国机械工业出版社,1998,21～27
[2] 彭一川,廖欣,莫凤兵.不同形状拉伐尔喷嘴中气流行为的研究[J].钢铁研究,1999,2:43～45
[3] 陆慧林,赵广播,别如山,刘文铁,李炳熙.管内气固两相流动的实验和模拟计算[J].工程热物理学报,1999,20(5):627～631
[4] 冯益华.新型陶瓷喷砂嘴的研究开发及其冲蚀磨损机理研究[D].博士学位论文.济南:山东大学,2003
[5] 孟立新,张唏,杨景顺.热喷涂表面预处理工艺的优化[J].表面技术,2005,34(4):55～57
[6] 郝建军,李会平,马跃进,幺永强.喷砂预处理在铸铁零件修复中的应用研究[J].农用机械学报,2003,34(4):120～123
[7] 李成贤.喷砂在零件表面处理中的应用[J].材料保护,1994,27(8):33～36
[8] 蔡日恒,吴登真.强化喷丸在汽车零件上的应用[J].汽车技术,1994,(1):33～34
[9] 李钦奉.喷砂技术及其表面清理效率的研究[J].中国修船,2003,(3):13～15
[10] 王晓明.环保喷砂机用气动砂阀的设计[J].新技术新工艺,2004,12:35
[11] 李勇,艾信友,肖春华.气力输送原理在喷砂和除尘中的应用[J].机械制造,1999,11:13～14
[12] 卯福生,王丽,冯益华.基于气固两相流理论的陶瓷喷砂嘴冲蚀磨损研究[J].山东轻工业学院学报,2005,15(2):1～4
[13] 李钦奉,王贵成.喷嘴直径对喷砂清理效率的影响[J].材料保护,2001,34(12):51～52
[14] 叶旭初,胡道和.CFD 技术与工程应用[J].中国水泥,2003,2:29～32
[15] 陶文铨.计算传热学的近代进展[M].北京:科学出版社,2000
[16] 刘晓波,华祖林,何国建.计算流体力学的科学计算可视化研究进展[J].水动力学研究与进展,2004,19(1):120～125
[17] 姚征,陈康民.CFD 通用软件综述[J].上海理工大学学报.2002,24(2):137～144
[18] 钟英杰,都晋燕,张雪梅.CFD 技术及在现代工业中的应用[J].浙江工业大学学报.2003,31(3):284～289
[19] 王世安,尹贵鲁.CFD 在飞机设计中的应用[J].航空科学技术,2002,6:33～36
[20] 常思勤,扈圣刚.计算流体力学进展及其在汽车设计中的应用[J].武汉汽车工业大学学报,1997,19(4):12～15
[21] 黄兴华,王道连,王如竹,张吉光.旋风分离器中气相流动特性及颗粒分离效率的数值研究[J].动力工程,2004,24(3):436～441
[22] 尹晔东,王运东,费维扬.计算流体力学(CFD)在化学工程中的应用[J].石化技术,2000,7(3):166～169
[23] 蔡荣泉.船舶计算流体力学的发展与应用[J].船舶,2002,4:8～13
[24] 戴建华,丁光宏,龚剑秋,杨新健,张晓龙.颅内动脉瘤的血液动力学二维数值模拟[J].复旦学报(自然科学版),2004,43(3) :392～397
[25] 谭洪卫.计算流体动力学在建筑环境工程上的应用[J].暖通空调 HV&AC,1999,29(4):31～36
[26] 别如山,杨励丹,李静海.渐缩渐扩管内径向颗粒浓度不均匀性的实验研究[J].化学反应工程与工艺,1996,12(1):106～109
[27] 章利特,徐廷相.缩放喷管内的气固两相流动和缩放喷管长度的研究[J].西安交通大学学报,2004,38(7):702～704
[28] 何枫,谢峻石,姚朝晖.超声速欠膨胀冲击射流的数值模拟[J].推进技术,2002,23(2):96～99
[29] 谢峻石,何枫.收缩喷嘴内部流道型线对射流流场的影响[J].机械开发,2000,4:42～48
[30] 毛亚黎.超声速喷流撞击平板的研究[D].硕士学位论文.长沙:国防科学技术大学,2000
[31] 傅德彬,姜毅.燃气射流气固两相数值模拟与颗粒冲刷分析[J].弹箭与制导学报,2004,24(1):63～66
[32] 周立行.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
[33] Fluent Inc., FLUENT 6.0 User's Guide. Fluent Inc., 2003
[34] C. Crowe, M. Sommerfield, and Yutaka Tsuji.Multiphase Flows with Droplets and Particles. CRC Press, 1998
[35] M.B.Abbott, D.R.Basco, Computational Fluid Dynamics-An Introduction for Engineers. Longman Scientific & Technical, Harlow, England, 1989
[36] B.E. Launder, D.B. Spalding, Lectures in Mathematical Models of Turbulence. Academic Press, London, 1972
[37] V. Yakhot, S.A. Orzag, Renormalization group analysis of turbulence:Basic theory. J Scient Comput. 1:3-11, 1986
[38] T.H. Shih, W.W. Liou, A. Shabbir, Z.G. Yang, J. Zhu, A new k-ε eddy viscosity model for high Reynolds number turbulent flows. Comput Fluids. 24(3):227-238,1995
[39] H.K. Versteeg, W. Malalasekera, An Introduction to Computational Fluid Dynamics: The Finite Volume Method. Wiley, New York, 1995
[40] Fluent Inc., GAMBIT Modeling Guide. Fluent Inc., 2003
[41] 王福军.计算流体动力学分析——CFD 软件原理与应用[M].北京:清华大学出版 社,2004
[42] 时爱民,苏铭德,刘季年.气体动力学基础[M].北京:科学出版社,1988
[43] 王文琪.两相流动[M].北京:水利电力出版社,1988
[44] Eugene S. Love, Carl E. Grigsby, Louise P. Lee, And Mildred J. wooling, Experimental and Theoretical Studies of Axisymmetric Free Jet. NASATRR-6, 1959
[45] 童秉纲,孔祥言,邓国华.气体动力学[M].北京:高等教育出版社,1990
[46] 韩占忠,王敬,兰小平.FLUENT 流体工程仿真计算实例与应用[M].北京:北京理工大学出版社,2004
[47] P. Spalart and S. Allmaras. A one-equation turbulence model for aerodynamic flows. Technical Report AIAA-92-0439, American Institute of Aeronautics and Astronautics, 1992
[48] J. Dacles-Mariani, G.G. Zilliac, J.S. Chow, and P. Bradshaw. Numerical/Experimental Study of a Wingtip Vortex in the Near Field. ALAA Journal, 33(9):1561-1568, 1995
[49] P.J. Lamont,B.L. Hunt, The Impingement of Underexpanded Axisymmetric Jet on Perpendicular and Inclined Flat Plate.Journal of Fluid Mechanics, Vol.100, part3, 1980
[50] J.K. Edwards, B.S. McLaury, and S.A. Shirazi. Evaluation of Alternative Pipe Bend Fittings in Erosive Service. In Proceedings of ASME FEDSM00:ASME 2000 Fluids Engineering Division Summer Meeting, Boston, June 2000
[2] 彭一川,廖欣,莫凤兵.不同形状拉伐尔喷嘴中气流行为的研究[J].钢铁研究,1999,2:43～45
[3] 陆慧林,赵广播,别如山,刘文铁,李炳熙.管内气固两相流动的实验和模拟计算[J].工程热物理学报,1999,20(5):627～631
[4] 冯益华.新型陶瓷喷砂嘴的研究开发及其冲蚀磨损机理研究[D].博士学位论文.济南:山东大学,2003
[5] 孟立新,张唏,杨景顺.热喷涂表面预处理工艺的优化[J].表面技术,2005,34(4):55～57
[6] 郝建军,李会平,马跃进,幺永强.喷砂预处理在铸铁零件修复中的应用研究[J].农用机械学报,2003,34(4):120～123
[7] 李成贤.喷砂在零件表面处理中的应用[J].材料保护,1994,27(8):33～36
[8] 蔡日恒,吴登真.强化喷丸在汽车零件上的应用[J].汽车技术,1994,(1):33～34
[9] 李钦奉.喷砂技术及其表面清理效率的研究[J].中国修船,2003,(3):13～15
[10] 王晓明.环保喷砂机用气动砂阀的设计[J].新技术新工艺,2004,12:35
[11] 李勇,艾信友,肖春华.气力输送原理在喷砂和除尘中的应用[J].机械制造,1999,11:13～14
[12] 卯福生,王丽,冯益华.基于气固两相流理论的陶瓷喷砂嘴冲蚀磨损研究[J].山东轻工业学院学报,2005,15(2):1～4
[13] 李钦奉,王贵成.喷嘴直径对喷砂清理效率的影响[J].材料保护,2001,34(12):51～52
[14] 叶旭初,胡道和.CFD 技术与工程应用[J].中国水泥,2003,2:29～32
[15] 陶文铨.计算传热学的近代进展[M].北京:科学出版社,2000
[16] 刘晓波,华祖林,何国建.计算流体力学的科学计算可视化研究进展[J].水动力学研究与进展,2004,19(1):120～125
[17] 姚征,陈康民.CFD 通用软件综述[J].上海理工大学学报.2002,24(2):137～144
[18] 钟英杰,都晋燕,张雪梅.CFD 技术及在现代工业中的应用[J].浙江工业大学学报.2003,31(3):284～289
[19] 王世安,尹贵鲁.CFD 在飞机设计中的应用[J].航空科学技术,2002,6:33～36
[20] 常思勤,扈圣刚.计算流体力学进展及其在汽车设计中的应用[J].武汉汽车工业大学学报,1997,19(4):12～15
[21] 黄兴华,王道连,王如竹,张吉光.旋风分离器中气相流动特性及颗粒分离效率的数值研究[J].动力工程,2004,24(3):436～441
[22] 尹晔东,王运东,费维扬.计算流体力学(CFD)在化学工程中的应用[J].石化技术,2000,7(3):166～169
[23] 蔡荣泉.船舶计算流体力学的发展与应用[J].船舶,2002,4:8～13
[24] 戴建华,丁光宏,龚剑秋,杨新健,张晓龙.颅内动脉瘤的血液动力学二维数值模拟[J].复旦学报(自然科学版),2004,43(3) :392～397
[25] 谭洪卫.计算流体动力学在建筑环境工程上的应用[J].暖通空调 HV&AC,1999,29(4):31～36
[26] 别如山,杨励丹,李静海.渐缩渐扩管内径向颗粒浓度不均匀性的实验研究[J].化学反应工程与工艺,1996,12(1):106～109
[27] 章利特,徐廷相.缩放喷管内的气固两相流动和缩放喷管长度的研究[J].西安交通大学学报,2004,38(7):702～704
[28] 何枫,谢峻石,姚朝晖.超声速欠膨胀冲击射流的数值模拟[J].推进技术,2002,23(2):96～99
[29] 谢峻石,何枫.收缩喷嘴内部流道型线对射流流场的影响[J].机械开发,2000,4:42～48
[30] 毛亚黎.超声速喷流撞击平板的研究[D].硕士学位论文.长沙:国防科学技术大学,2000
[31] 傅德彬,姜毅.燃气射流气固两相数值模拟与颗粒冲刷分析[J].弹箭与制导学报,2004,24(1):63～66
[32] 周立行.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
[33] Fluent Inc., FLUENT 6.0 User's Guide. Fluent Inc., 2003
[34] C. Crowe, M. Sommerfield, and Yutaka Tsuji.Multiphase Flows with Droplets and Particles. CRC Press, 1998
[35] M.B.Abbott, D.R.Basco, Computational Fluid Dynamics-An Introduction for Engineers. Longman Scientific & Technical, Harlow, England, 1989
[36] B.E. Launder, D.B. Spalding, Lectures in Mathematical Models of Turbulence. Academic Press, London, 1972
[37] V. Yakhot, S.A. Orzag, Renormalization group analysis of turbulence:Basic theory. J Scient Comput. 1:3-11, 1986
[38] T.H. Shih, W.W. Liou, A. Shabbir, Z.G. Yang, J. Zhu, A new k-ε eddy viscosity model for high Reynolds number turbulent flows. Comput Fluids. 24(3):227-238,1995
[39] H.K. Versteeg, W. Malalasekera, An Introduction to Computational Fluid Dynamics: The Finite Volume Method. Wiley, New York, 1995
[40] Fluent Inc., GAMBIT Modeling Guide. Fluent Inc., 2003
[41] 王福军.计算流体动力学分析——CFD 软件原理与应用[M].北京:清华大学出版 社,2004
[42] 时爱民,苏铭德,刘季年.气体动力学基础[M].北京:科学出版社,1988
[43] 王文琪.两相流动[M].北京:水利电力出版社,1988
[44] Eugene S. Love, Carl E. Grigsby, Louise P. Lee, And Mildred J. wooling, Experimental and Theoretical Studies of Axisymmetric Free Jet. NASATRR-6, 1959
[45] 童秉纲,孔祥言,邓国华.气体动力学[M].北京:高等教育出版社,1990
[46] 韩占忠,王敬,兰小平.FLUENT 流体工程仿真计算实例与应用[M].北京:北京理工大学出版社,2004
[47] P. Spalart and S. Allmaras. A one-equation turbulence model for aerodynamic flows. Technical Report AIAA-92-0439, American Institute of Aeronautics and Astronautics, 1992
[48] J. Dacles-Mariani, G.G. Zilliac, J.S. Chow, and P. Bradshaw. Numerical/Experimental Study of a Wingtip Vortex in the Near Field. ALAA Journal, 33(9):1561-1568, 1995
[49] P.J. Lamont,B.L. Hunt, The Impingement of Underexpanded Axisymmetric Jet on Perpendicular and Inclined Flat Plate.Journal of Fluid Mechanics, Vol.100, part3, 1980
[50] J.K. Edwards, B.S. McLaury, and S.A. Shirazi. Evaluation of Alternative Pipe Bend Fittings in Erosive Service. In Proceedings of ASME FEDSM00:ASME 2000 Fluids Engineering Division Summer Meeting, Boston, June 2000