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Numerical Simulation of Two-Phase Flow in the Second Header of MAC Condenser
Technical Paper
2019-01-1065
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Phase separation circuiting have been proved in the past to effectively improve the performance of mobile air conditioning (MAC) condensers. In the vertical second header of the condenser, liquid separates from vapor mainly due to gravity, leaving vapor-rich flow with higher heat transfer coefficient to go into the upper passes. The condenser effectiveness is improved in this way. However, separation is usually not perfect, expressed through the separation efficiency (ηl and ηv).
This paper presents the numerical study of phase separation phenomena in the second header. The Euler-Euler method of Computational Fluid Dynamics (CFD) is used. Simulations are conducted for two-phase refrigerant R-134a for MAC application. Inlet mass flow rate is simulated at values of 16 g∙s-1, 20 g∙s-1, and 30 g∙s-1 for 21 inlet microchannel tubes, which is the same 1st-pass tube number as of a real separation condenser. Corresponding mass fluxes are 166 kg∙m-2∙s-1, 207 kg∙m-2∙s-1, and 311 kg∙m-2∙s-1. Inlet quality is simulated to be 0.16 to 0.21, which was covered by past flow separation efficiency experiments. The CFD simulation is compared to the experimental results with flow visualization and the results of a simple mechanistic model based on empirical correlations. Results agree well with each other, which provides a backup for the physical understanding of two-phase flow inside the second header. Conclusion can be drawn that liquid separation efficiency ηl decreases with increasing ηv following a step-wise decreasing trend. Pressure and streamline profiles inside the header are revealed. Reversed flow can be seen on the cross section of the header.
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Li, J. and Hrnjak, P., "Numerical Simulation of Two-Phase Flow in the Second Header of MAC Condenser," SAE Technical Paper 2019-01-1065, 2019, https://doi.org/10.4271/2019-01-1065.Data Sets - Support Documents
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References
- Ye , L. , Tong , M.W. , and Zeng , X. Design and Analysis of Multiple Parallel-Pass Condensers International Journal of Refrigeration 32 6 1153 1161 2009
- Luo , X. , Yi , Z. , Chen , Z. , Chen , Y. et al. Performance Comparison of the Liquid-Vapor Separation, Parallel Flow, and Serpentine Condensers in the Organic Rankine Cycle Applied Thermal Engineering 94 435 448 2016
- Zhong , T. , Chen , Y. , Hua , N. , Zheng , W. et al. In-Tube Performance Evaluation of an Air-Cooled Condenser with Liquid-Vapor Separator Applied Energy 136 968 978 2014
- Davies , W.A. III , Kang , Y. , Hrnjak , P. , and Jacobi , A.M. Method for Evaluating the Effect of Inclination on the Performance of Large Flattened-Tube Steam Condensers with Visualization of Flow Regimes Applied Thermal Engineering 138 934 941 2018
- Liu , Q. , Gilden , R.M. , and Luther , J.P. 1998
- Oh , K. , Lee , S. , Park , T. , and Kim , Y. 2003
- Li , J. and Hrnjak , P. Separation in Condensers as a Way to Improve Efficiency Int. J. Refrigeration 79 1 9 2017a
- Li , J. and Hrnjak , P. Improvement of Condenser Performance by Phase Separation Confirmed Experimentally and by Modeling Int. J. Refrigeration 78 60 69 2017b
- Datta , A.B. and Majumdar , A.K. Flow Distribution in Parallel and Reverse Flow Manifolds International Journal of Heat and Fluid Flow 2 4 253 262 1980
- Bajura , R.A. and Jones , E.H. Flow Distribution Manifolds Journal of Fluids Engineering 98 4 654 665 1976
- Patankar , S.V. and Spalding , D.B. A Calculation Procedure for Heat, Mass and Momentum Transfer in Three Dimensional Parabolic Flows Int. J. Heat Mass Transfer 15 1787 1806 1972
- Datta , A.B. and Majumdar , A.K. A Calculation Procedure for Two Phase Flow Distribution in Manifolds with and without Heat Transfer Int. J. Heat Mass Transfer 26 9 1321 1328 1983
- Wang , X.A. and Yu , P. Isothermal Flow Distribution in Header Systems Int. J. Sol. Energy 7 3 159 169 1989
- Yin , J.M. , Bullard , C.W. , and Hrnjak , P.S. Single-Phase Pressure Drop Measurements in a Microchannel Heat Exchanger Heat Transfer Eng 23 4 3 12 2002
- Idelchik , I.E. Handbook of Hydraulic Resistance Third New York Begell House 1994
- Ablanque , N. , Oliet , C. , Rigola , J. , Prez-Segarra , C. et al. Two-Phase Flow Distribution in Multiple Tubes Int. J. Thermal Sci. 49 909 921 2010
- Ren , T. , Ding , G. , Wang , T. , and Hu , H. A General Three-Dimensional Simulation Approach for Micro-Channel Heat Exchanger Based on Graph Theory Applied Thermal Engineering 59 1-2 660 674 2013
- Hwang , S.T. , Soliman , H.M. , and Lahey , R.T. Phase Separation in Impacting Wyes and Tees Int. J Multiphase Flow 15 6 965 975 1989 10.1016/0301-9322(89)90024-4
- Ha , M.Y. , Kim , C.H. , Jung , Y.W. , and Heo , S.G. Two-Phase Flow Analysis in Multi-Channel Journal of Mechanical Science Technology 20 840 848 2006
- Zhang , Z. and Li , Y.Z. CFD Simulation on Inlet Configuration of Plate-Fin Heat Exchangers Cryogenics 43 673 678 2003
- Wen , J. and Li , Y.Z. Study of Flow Distribution and Its Improvement on the Header of Plate-Fin Heat Exchanger Cryogenics 44 823 831 2004
- Fei , P. and Hrnjak , P.S. 2004
- Li , G. , Frankel , S. , Braun , J.E. , and Groll , E.A. Application of CFD models to two-phase flow in refrigerant distributors Hvac & R Research 11 45 62 2005
- Stevanovic , V. , Cucuz , S. , Carl-Meissner , W. , Maslovaric , B. et al. A Numerical Investigation of the Refrigerant Maldistribution from a Header Towards Parallel Channels in an Evaporator of Automotive Air Conditioning System Int. J. Heat Mass Transf. 55 3335 3343 2012
- Stevanovic , V.D. and Hrnjak , P. Numerical Simulation of Three Dimensional Two-Phase Flow and Prediction of Oil Retention in an Evaporator of the Automotive Air Conditioning System Applied Thermal Engineering 117 468 480 2017
- Li , J. and Hrnjak , P. Phase Separation in Second Header of MAC Condenser SAE Technical Paper 2015-01-1694 2015 2015 10.4271/2015-01-1694
- Li , J. and Hrnjak , P. The Analysis of Phase Separation in Vertical Headers of Microchannel HEs SAE Technical Paper 2016-01-0253 2016 2016 10.4271/2016-01-0253
- ANSYS-Fluent 2018
- NIST 2010
- Clift , R. , Grace , J.R. , and Weber , M.E. Bubbles, Drops, and Particles New York Academic Press 1978
- Schiller , L. and Naumann , A. uber die grundlegenden Berechnungen bei der Schwerkraftaufbereitung Ver. Deut Ing 77 318 1933
- Schiller , L. and Naumann , Z. A Drag Coefficient Correlation Vdi Zeitung 77 318 320 1935
- Ganan-Calvo , A.M. , Davila , J. , and Barrero , A. Current and Droplet Size in the Electrospraying of Liquids. Scaling Laws Journal of Aerosol Science 28 2 249 275 1997
- Varga , C.M. , Lasheras , J.C. , and Hopfinger , E.J. Initial Breakup of a Small-Diameter Liquid Jet by a High-Speed Gas Stream Journal of Fluid Mechanics 497 405 434 2003
- Marmottant , P. and Villermaux , E. On Spray Formation Journal of Fluid Mechanics 498 73 111 2004
- Roh , C.W. and Kim , M.S. Macroscopic Spray Behavior and Atomization Characteristics of Refrigerant R22 Injection under Increased Ambient Pressure Int. J. Heat Mass Transfer 55 11-12 3307 3315 2012
- Wang , J.X. , Li , Y.Z. , Li , J.X. , Li , C. et al. A Gas-Atomized Spray Cooling System Integrated with an Ejector Loop: Ejector Modeling and Thermal Performance Analysis Energy Conversion and Management 180 106 118 2019
- Beale , J.C. and Reitz , R.D. Modeling Spray Atomization with the Kelvin-Helmholtz/Rayleigh-Taylor Hybrid Model Atomization and Sprays 9 6 1999
- Legendre , D. and Magnaudet , J. The Lift Force on a Spherical Bubble in a Viscous Linear Shear Flow J. Fluid Mech. 368 81 126 1998
- Patankar , S.V. Numerical Heat Transfer and Fluid Flow Taylor & Francis 1980
- Barth , T.J. and Jespersen , D.C. 1989
- Li , J. and Hrnjak , P. Phase Separation in Vertical Header of Microchannel Condensers - A Mechanistic Model Proceedings of the ASME 2018 5th Joint US-European Fluids Engineering Division Summer Conference Montreal, Quebec, Canada 2018
- Taitel , Y. , Bornea , D. , and Dukler , A.E. Modelling Flow Pattern Transitions for Steady upward Gas-Liquid Flow in Vertical Tubes AIChE Journal 26 3 345 354 1980 https://doi.org/10.1002/aic.690260304