曳力模型和湍流模型对内环流反应器数值模拟的影响
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摘要
研究了曳力模型和湍流模型对气升式内环流反应器流体力学参数的影响,进一步证实了DBS-Local曳力模型在气升式内环流反应器中的适用性。结果表明:曳力模型决定了是否可以模拟出下降管中的气体;而曳力模型和湍流模型共同作用,决定了气含率模拟结果的准确性。Schiller-Naumann、Tomiyama、Grace、Ishii-Zuber这4种曳力模型均无法预测出下降管含气这一现象,而DBS-Local曳力模型能够模拟出下降管中的气体。DBS-Local曳力模型与standard k-εmixture湍流模型组合,对气含率的预测值与实验值较为接近,而与RNG k-ε dispersed湍流模型组合,对轴向液速的预测值与实验值更为接近。
The influence of drag models and turbulence models on the hydrodynamic parameters in an air-lift internal-loop reactor is evaluated. Drag models determine the existence of gas in downcomer, and drag models and turbulence models jointly determine the accuracy of the simulation of gas holdup. Using uniform size bubbles, the Schiller-Naumann, Tomiyama, Grace and Ishii-Zuber drag models are only suitable for lower superficial gas velocity, and there is no gas in downcomer. The capability of DBS-Local drag model was confirmed. Compared with the other four drag models, only DBS-Local drag model can predict the existence of gas in downcomer. DBS-Local drag model combining with the standard k-ε mixture turbulence model can well predict gas holdup, and combining with RNG k-ε dispersed turbulence model can better predict liquid velocity.
The influence of drag models and turbulence models on the hydrodynamic parameters in an air-lift internal-loop reactor is evaluated. Drag models determine the existence of gas in downcomer, and drag models and turbulence models jointly determine the accuracy of the simulation of gas holdup. Using uniform size bubbles, the Schiller-Naumann, Tomiyama, Grace and Ishii-Zuber drag models are only suitable for lower superficial gas velocity, and there is no gas in downcomer. The capability of DBS-Local drag model was confirmed. Compared with the other four drag models, only DBS-Local drag model can predict the existence of gas in downcomer. DBS-Local drag model combining with the standard k-ε mixture turbulence model can well predict gas holdup, and combining with RNG k-ε dispersed turbulence model can better predict liquid velocity.
引文
[1]张伟鹏.气液环流反应器中宏观混合及微观混合的研究[D].北京:中国科学院大学,2013.ZHANG W P.Investigation on macro-and micro-mixing in gas-liquid loop reactor[D].Beijing:University of Chinese Academy of Sciences,2013.
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[3]BELLO R A,RINSONOB C W,MOOYOUNG M.Gas holdup and overall volumetric oxygen transfer coefficient in airlift contactors[J].Biotechnology&Bioengineering,1985,27(3):369-81.
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[12]徐春燕,池春榕,刘祖文,等.气升式反应器内流动与传质研究进展[J].有色金属科学与工程,2016,7(5):110-118.XU C Y,CHI C Y,LIU Z W,et al.Research status of flow and mass transfer of air lift reactor[J].Nonferrous Metals Science and Engineering,2016,7(5):110-118.
[13]林文才,毛在砂.气升式环流反应器中的流体动力学研究(Ⅱ):实验及模型结果分析[J].化工学报,1995,46(3):290-297.LIN W C,MAO Z S.A fluid dynamics model for air-lift loop reactors(Ⅱ):Analyses on experimental data and calculated results[J].Journal of Chemical Industry and Engineering(China),1995,46(3):290-297.
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[15]MORADI S,RAJABI Z,MOHAMMADI M,et al.3 dimensional hydrodynamic analysis of concentric draft tube airlift reactors with different tube diameters[J].Mathematical&Computer Modelling An International Journal,2013,57(5/6):1184-1189.
[16]吴宗应,杨宁.曳力模型对模拟鼓泡塔气含率的影响[J].化工学报,2010,61(11):2817-2822.WU Z Y,YANG N.Effect of drag models on simulation of gas hold-up in bubble columns[J].CIESC Journal,2010,61(11):2817-2822.
[17]HUANG Q,YANG C,YU G,et al.Sensitivity study on modeling an internal airlift loop reactor using a steady 2D two-fluid model[J].Chemical Engineering&Technology,2010,31(12):1790-1798.
[18]张涛.内循环流化床反应器流动传质特性的计算流体力学模拟研究[D].广州:华南理工大学,2012.ZHANG T.Simulation of mass transfer and hydrodynamic characteristics in internal loop fluidized bed reactor by computational fluid dynamics method[D].Guangzhou:South China University of Technology,2012.
[19]XU T T,JIANG X D,YANG N,et al.CFD simulation of internal-loop airlift reactor using EMMS drag model[J].Particuology,2015,19(2):124-132.
[20]JIANG X D,YANG N,YANG B L.Computational fluid dynamics simulation of hydrodynamics in the riser of an external loop airlift reactor[J].Particuology,2016,27(4):95-101.
[21]许婷婷.DBS曳力模型与湍流模型对气液CFD模拟的影响[D].北京:中国科学院大学,2014.XU T T.Influence of DBS drag model and turbulence models on CFD simulation of gas-liquid flow[D].Beijing:University of Chinese Academy of Sciences,2014.
[22]YANG N,CHEN J H,ZHAO H,et al.Explorations on the multi-scale flow structure and stability condition in bubble columns[J].Chemical Engineering Science,2007,62(24):6978-6991.
[23]YANG N,CHEN J H,GE W,et al.A conceptual model for analyzing the stability condition and regime transition in bubble columns[J].Chemical Engineering Science,2010,65(1):517-526.
[24]YANG N,WU Z Y,CHEN J H,et al.Multi-scale analysis of gas-liquid interaction and CFD simulation of gas-liquid flow in bubble columns[J].Chemical Engineering Science,2011,66(14):3212-3222.
[25]YANG N.A multi-scale framework for CFD modelling of multi-phase complex systems based on the EMMS approach[J].Progress in Computational Fluid Dynamics,2012,12(2/3):220-229.
[26]XIAO Q,YANG N,LI J H.Stability-constrained multi-fluid CFD models for gas-liquid flow in bubble columns[J].Chemical Engineering Science,2013,100(100):279-292.
[27]SCHILLER L,NAUMANN A.A drag coefficient correlation[J].Vdi Zeitung,1935,77:318-320.
[28]TOMIYAMA A.Struggle with computational bubble dynamics[J].Multiphase Science and Technology,1998,10(4):369-405.
[29]ISHII M,ZUBER N.Drag coefficient and relative velocity in bubbly,droplet or particulate flows[J].AICh E Journal,1979,25(5):843-855.
[30]GRACE J R.Shapes and velocities of single drops and bubbles moving freely through immiscible liquids[J].Transactions of the Institution of Chemical Engineers,1976,54(3):167-173.
[2]LU W J,HWANG S J,CHANG C M.Liquid velocity and gas holdup in three-phase internal loop airlift reactors with low-density particles[J].Chemical Engineering Science,1995,50(8):1301-1310.
[3]BELLO R A,RINSONOB C W,MOOYOUNG M.Gas holdup and overall volumetric oxygen transfer coefficient in airlift contactors[J].Biotechnology&Bioengineering,1985,27(3):369-81.
[4]FU C C,FAN L S,WU W T.Flow regime transitions in an internal-loop airlift reactor[J].Chemical Engineering&Technology,2010,30(8):1077-1082.
[5]祝俊丽.气升式内环流反应器流体力学性能实验研究及数值模拟[D].杭州:浙江工业大学,2005.ZHU J L.Hydrodynamic studies and numerical simulation of an internal airlift loop reactor[D].Hangzhou:Zhejiang University of Technology,2005.
[6]HEIJNEN J J,HOLS J,VAN DER LANS R G J M,et al.A simple hydrodynamic model for the liquid circulation velocity in a full-scale two-and three-phase internal airlift reactor operating in the gas recirculation regime[J].Chemical Engineering Science,1997,52(15):2527-2540.
[7]QIE S Y,GAO F,LIU C,et al.Effects of different draft baffles on the hydrodynamics in internal-loop airlift reactors[J].Journal of Tianjin University,2015,21(5):446-452.
[8]SIMCIK M,MOTA A,RUZICKA M C,et al.CFD simulation and experimental measurement of gas holdup and liquid interstitial velocity in internal loop airlift reactor[J].Chemical Engineering Science,2011,66(14):3268-3279.
[9]王铁峰.气液(浆)反应器流体力学行为的实验研究和数值模拟[D].北京:清华大学,2004.WANG T F.Experimental study and numerical simulation on the hydrodynamics in gas-liquid(slurry)reactors[D].Beijing:Tsinghua University,2004.
[10]李飞,王保国,陈筛林,等.新型多级环流反应器流体力学研究[J].化学工程,2006,34(2):37-40.LI F,WANG B G,CHEN S L,et al.Study on the hydrodynamics in multi stage loop reactor[J].Chemical Engineering(China),2006,34(2):37-40.
[11]SUN S,LIU C,WEI W,et al.Hydrodynamics of an annulus airlift reactor[J].Powder technology,2006,162(3):201-207
[12]徐春燕,池春榕,刘祖文,等.气升式反应器内流动与传质研究进展[J].有色金属科学与工程,2016,7(5):110-118.XU C Y,CHI C Y,LIU Z W,et al.Research status of flow and mass transfer of air lift reactor[J].Nonferrous Metals Science and Engineering,2016,7(5):110-118.
[13]林文才,毛在砂.气升式环流反应器中的流体动力学研究(Ⅱ):实验及模型结果分析[J].化工学报,1995,46(3):290-297.LIN W C,MAO Z S.A fluid dynamics model for air-lift loop reactors(Ⅱ):Analyses on experimental data and calculated results[J].Journal of Chemical Industry and Engineering(China),1995,46(3):290-297.
[14]沈荣春,束忠明,黄发瑞.气体分布器结构对气升式环流反应器内气液两相流动的影响[J].化学反应工程与工艺,2007,23(5):422-429.SHEN R C,SHU Z M,HUANG F R.Effect of gas sparger geometry on gas-liquid two-phase flow in an airlift loop reactor[J].Chemical Reaction Engineering and Technology,2007,23(5):422-429.
[15]MORADI S,RAJABI Z,MOHAMMADI M,et al.3 dimensional hydrodynamic analysis of concentric draft tube airlift reactors with different tube diameters[J].Mathematical&Computer Modelling An International Journal,2013,57(5/6):1184-1189.
[16]吴宗应,杨宁.曳力模型对模拟鼓泡塔气含率的影响[J].化工学报,2010,61(11):2817-2822.WU Z Y,YANG N.Effect of drag models on simulation of gas hold-up in bubble columns[J].CIESC Journal,2010,61(11):2817-2822.
[17]HUANG Q,YANG C,YU G,et al.Sensitivity study on modeling an internal airlift loop reactor using a steady 2D two-fluid model[J].Chemical Engineering&Technology,2010,31(12):1790-1798.
[18]张涛.内循环流化床反应器流动传质特性的计算流体力学模拟研究[D].广州:华南理工大学,2012.ZHANG T.Simulation of mass transfer and hydrodynamic characteristics in internal loop fluidized bed reactor by computational fluid dynamics method[D].Guangzhou:South China University of Technology,2012.
[19]XU T T,JIANG X D,YANG N,et al.CFD simulation of internal-loop airlift reactor using EMMS drag model[J].Particuology,2015,19(2):124-132.
[20]JIANG X D,YANG N,YANG B L.Computational fluid dynamics simulation of hydrodynamics in the riser of an external loop airlift reactor[J].Particuology,2016,27(4):95-101.
[21]许婷婷.DBS曳力模型与湍流模型对气液CFD模拟的影响[D].北京:中国科学院大学,2014.XU T T.Influence of DBS drag model and turbulence models on CFD simulation of gas-liquid flow[D].Beijing:University of Chinese Academy of Sciences,2014.
[22]YANG N,CHEN J H,ZHAO H,et al.Explorations on the multi-scale flow structure and stability condition in bubble columns[J].Chemical Engineering Science,2007,62(24):6978-6991.
[23]YANG N,CHEN J H,GE W,et al.A conceptual model for analyzing the stability condition and regime transition in bubble columns[J].Chemical Engineering Science,2010,65(1):517-526.
[24]YANG N,WU Z Y,CHEN J H,et al.Multi-scale analysis of gas-liquid interaction and CFD simulation of gas-liquid flow in bubble columns[J].Chemical Engineering Science,2011,66(14):3212-3222.
[25]YANG N.A multi-scale framework for CFD modelling of multi-phase complex systems based on the EMMS approach[J].Progress in Computational Fluid Dynamics,2012,12(2/3):220-229.
[26]XIAO Q,YANG N,LI J H.Stability-constrained multi-fluid CFD models for gas-liquid flow in bubble columns[J].Chemical Engineering Science,2013,100(100):279-292.
[27]SCHILLER L,NAUMANN A.A drag coefficient correlation[J].Vdi Zeitung,1935,77:318-320.
[28]TOMIYAMA A.Struggle with computational bubble dynamics[J].Multiphase Science and Technology,1998,10(4):369-405.
[29]ISHII M,ZUBER N.Drag coefficient and relative velocity in bubbly,droplet or particulate flows[J].AICh E Journal,1979,25(5):843-855.
[30]GRACE J R.Shapes and velocities of single drops and bubbles moving freely through immiscible liquids[J].Transactions of the Institution of Chemical Engineers,1976,54(3):167-173.