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Electrical conductivity effect on MHD mixed convection of nanofluid flow over a backward-facing step

导电性对纳米磁流体后向混合对流的影响

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Abstract

In this study, magneto-hydrodynamics (MHD) mixed convection effects of Al2O3-water nanofluid flow over a backward-facing step were investigated numerically for various electrical conductivity models of nanofluids. A uniform external magnetic field was applied to the flow and strength of magnetic field was varied with different values of dimensionless parameter Hartmann number (Ha=0, 10, 20, 30, 40). Three different electrical conductivity models were used to see the effects of MHD nanofluid flow. Besides, five different inclination angles between 0º~90º is used for the external magnetic field. The problem geometry is a backward-facing step which is used in many engineering applications where flow separation and reattachment phenomenon occurs. Mixed type convective heat transfer of backward-facing step was examined with various values of Richardson number (Ri=0.01, 0.1, 1, 10) and four different nanoparticle volume fractions (ø=0.01, 0.015, 0.020, 0.025) considering different electrical conductivity models. Finite element method via commercial code COMSOL was used for computations. Results indicate that the addition of nanoparticles enhanced heat transfer significantly. Also increasing magnetic field strength and inclination angle increased heat transfer rate. Effects of different electrical conductivity models were also investigated and it was observed that they have significant effects on the fluid flow and heat transfer characteristics in the presence of magnetic field.

摘要

本文对纳米磁流体的几种电导率模型进行了数值模拟, 研究了Al2O3-水纳米磁流体后向流动的 混合对流效应。对流体施加均匀的外部磁场时, 通过改变无量纲参数Hartmann 数(Ha=0, 10, 20, 30, 40)实现磁场强度的变化。应用3 种不同的电导率模型监测纳米磁流体的流动。同时, 在研究过程中 还选取了0°~90°范围内的5 中倾角下的外部磁场。后向流动常用于求解流体分流和再合流现象的工 程问题。根据不同电导率模型, 采用不同的 Richardson 数(Ri=0.01, 0.1, 1, 10)和4 种不同的纳米粒 子体积分数(ø=0.01, 0.015, 0.02, 0.025), 对混合型后向流的对流换热进行研究。采用商业代码 COMSOL 有限元方法进行计算。结果表明, 添加纳米颗粒增强了传热效果, 增加磁场强度和倾角也增加了热传 递速率。在对流体流动施加外部磁场的情况下, 不同电导率模型对流体的流动和传热效果也有不同的 影响。

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References

  1. LEE S, CHOI S U S, LI S, EASTMAN J A. Measuring thermal conductivity of fluids containing oxide nanoparticles [J]. Journal of Heat Transfer, 1999, 121: 280–289.

    Article  Google Scholar 

  2. EASTMAN J A, CHOI U S, LI S, THOMPSON L J, LEE S. Enhanced thermal conductivity through the development of nanofluids [C]// Materials Research Society Symposium, 457: 3–11. Pittsburgh, PA, USA, 1997.

    Article  Google Scholar 

  3. WANG X, XU X, CHOI S U S. Thermal conductivity of nanoparticle-fluid mixture [J]. Journal of Thermophysics and Heat Transfer, 1999, 13(4): 474–480.

    Article  Google Scholar 

  4. XUAN Y M, LI Q. Investigation on convective heat transfer and flow features of nanofluids [J]. ASME Journal of Heat Transfer, 2003, 125: 151–155.

    Article  Google Scholar 

  5. DUANGTHONGSUK W, WONGWISES S. An experimental study on the heat transfer performance and pressure drop of TiO2-water nanofluids flowing under a turbulent flow regime [J]. International Journal of Heat Mass Transfer, 2010, 53 (1-3): 334–344.

    Article  Google Scholar 

  6. PAK B C, CHO Y I. Hydrodynamic and heat transfer study of dispersed fluids with submicronmetallic oxide particles [J]. Exp Heat Transfer, 1998, 11: 151–170.

    Article  Google Scholar 

  7. SIAVASHI M, JAMALI M. Optimal selection of annulus radius ratio to enhance heat transfer with minimum entropy generation in developing laminar forced convection of water-Al2O3 nanofluid flow [J]. Journal of Central South University, 2017, 24: 1850–1865.

    Article  Google Scholar 

  8. HAQUE A K M, KWON S, KIM J, NOH J, HUH S, CHUNG H, JEONG H. An experimental study on thermal characteristics of nanofluid with graphene and multi-wall carbon nanotubes [J]. Journal of Central South University, 2015, 22: 3202–3210.

    Article  Google Scholar 

  9. MAHMOODI M, KANDELOUSI SH. Kerosene-alumina nanofluid flow and heat transfer for cooling application [J]. Journal of Central South University, 2016, 23: 983–990.

    Article  Google Scholar 

  10. ASHRAF M B, HAYAT T, ALSAEDI A, SHEHZAD S A. Convective heat and mass transfer in MHD mixed convection flow of Jeffrey nanofluid over a radially stretching surface with thermal radiation [J]. Journal of Central South University, 2015, 22: 1114–1123.

    Article  Google Scholar 

  11. SARI M R, KEZZAR M, ADJABI R. Heat transfer of copper/water nanofluid flow through converging-diverging channel [J]. Journal of Central South University, 2016, 23: 484–496.

    Article  Google Scholar 

  12. AHMED A, NADEEM S. Biomathematical study of timedependent flow of a Carreau nanofluid through inclined catheterized arteries with overlapping stenosis [J]. Journal of Central South University, 2017, 24: 2725–2744.

    Article  Google Scholar 

  13. AMINOSSADATI S M, RAISI A, GHASEMI B. Effects of J. Cent. South Univ. (2019) 26: 11333–1145 1144 magnetic field on nanofluid forced convection in a partially heated microchannel [J]. International Journal of Non-Linear Mechanics, 2011, 46: 1373–1382.

    Article  Google Scholar 

  14. RASHIDI M M, MOHAMMAD N, MARZIEH K, NAJIB L. Numerical investigation of magnetic field effect on mixed convection heat transfer of nanofluid in a channel with sinusoidal walls [J]. Journal of Magnetism and Magnetic Materials, 2016, 401: 159–168.

    Article  Google Scholar 

  15. SHEIKHOLESLAMI M, GORJI B, ELLAHI M R, HASSAN M. Effects of MHD on Cu-waternanofluid flow and heat transfer by means of CVFEM [J]. Journal of Magnetism and Magnetic Materials, 2014, 349: 188–200.

    Article  Google Scholar 

  16. SHEIKHOLESLAMI M, GANJI D D, SOLEIMANI S. Magnetic field effect on nanofluid flow and heat transfer using KKL model [J]. Journal of the Taiwan Institute of Chemical Engineers, 2014, 45: 795–807.

    Article  Google Scholar 

  17. SHEIKHOLESLAMI M, GORJI B, GANJ D D, SOLEIMANI S. Heat flux boundary condition for nanofluid filled enclosure in presence of magnetic field [J]. Journal of Molecular Liquids, 2014, 193: 174–184.

    Article  Google Scholar 

  18. SHEIKHOLESLAMI M, GANJI D D, ZIABAKHSH Z. Transport of Magnetohydrodynamic nanofluid in a porous media [J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017, 520: 201–212.

    Article  Google Scholar 

  19. SELIMEFENDIGIL F, ÖZTOP H F. Numerical study of MHD mixed convection in a nanofluid filled lid driven square enclosure with a rotating cylinder [J]. International Journal Heat Mass Transfer, 2014, 78: 741–754.

    Article  Google Scholar 

  20. LARIMI M M, GHANAAT A, RAMIAR A, RANJBAR A. Forced convection heat transfer in a channel under the influence of various non-uniform transverse magnetic field arrangements [J]. International Journal of Mechanical Sciences, 2016, 118: 110–112.

    Article  Google Scholar 

  21. ABU-NADA E. Application of nanofluids for heat transfer enhancement of separated flows encountered in a backward facing step [J]. International Journal of Heat and Mass Transfer, 2008, 29: 242–249.

    Google Scholar 

  22. KHERBEET A S, MOHAMMED H A, MUNISAMY K M, SALMAN B H. The effect of nanofluids flow on mixed convection heat transfer over microscale backward-facing step [J]. International Journal of Heat and Mass Transfer, 2012, 55: 5870–5881.

    Article  Google Scholar 

  23. KHERBEET A S, MOHAMMED H A, SALMAN B H, AHMED H E, ALAWI O A. Experimental and numerical study of nanofluid flow and heat transfer over microscale backward-facing step [J]. International Journal of Heat and Mass Transfer, 2014, 79: 858–867.

    Article  Google Scholar 

  24. SELIMEFENDIGIL F, ÖZTOP H F. Numerical investigation and reduced order model of mixed convection at a backward facing step with a rotating cylinder subjected to nanofluid [J]. Computers & Fluids, 2015, 109: 27–37.

    Article  Google Scholar 

  25. SELIMEFENDIGIL F, ÖZTOP H F. Forced convection and thermal predictions of pulsating nanofluid flow over a backward facing step with a corrugated bottom wall [J]. International Journal of Heat and Mass Transfer, 2017, 110: 231–247.

    Article  Google Scholar 

  26. MOHAMMED H A, AL-ASWADI A, ABU-MULAWEH H, SHUAIB N H. Influence of nanofluids on mixed convective heat transfer over a horizontal backward facing step [J]. Heat Transfer Asian Research, 2011, 40: 287–307.

    Article  Google Scholar 

  27. MOHAMMED H A, AL-ASWADI A A, YUSOFF M Z, SAIDUR R. Mixed convective flows over backward facing step in a vertical duct using various nanofluids buoyancyassisting case [J]. Thermophys Aeromech, 2012, 42(1): 1–30.

    Google Scholar 

  28. MOHAMMED H A, ALAWI O A, WAHID M A. Mixed convective nanofluid flow in a channel having backwardfacing step with a baffle [J]. Powder Technology, 2015, 275: 329–343.

    Article  Google Scholar 

  29. AL-ASWADI A A, MOHAMMED H A, SHUAIB N H, CAMPO A. Laminar forced convection flow over a backward facing step using nanofluids [J]. International Communications in Heat and Mass Transfer, 2010, 37: 950–957.

    Article  Google Scholar 

  30. HESHMATI A, MOHAMMED H A, DARUS A N. Mixed convection heat transfer of nanofluids over backward facing step having a slotted baffle [J]. Applied Mathematics and Computation, 2014, 240: 368–386.

    Article  MathSciNet  MATH  Google Scholar 

  31. SELIMEFENDIGIL F, OZTOP H F. Influence of inclination angle of magnetic field on mixed convection of nanofluid flow over a backward facing step and entropy generation [J]. Advanced Powder Technology, 2015, 26: 1663–1675.

    Article  Google Scholar 

  32. MAXWELL J C. A treatise on electricity and magnetism [M]. Oxford, UK: Clarendon Press, 1881.

    Google Scholar 

  33. BRUGGEMAN D A G. The calculation of various physical constants of heterogeneous substances I. The dielectric constants and conductivities of mixtures composed of isotropic substances [J]. Ann Phys, 1935, 24: 636–664.

    Article  Google Scholar 

  34. GANGULY S, SIKDAR S, BASU S. Experimental investigation of the effective electrical conductivity of aluminum oxide nanofluids [J]. Powder Technology, 2009, 196: 326–330.

    Article  Google Scholar 

  35. MINEA A A, LUCIU R S. Investigations on electrical conductivity of stabilized water based Al2O3 nanofluids [J]. Microfluidics and Nanofluidics, 2012, 13: 977–985.

    Article  Google Scholar 

  36. CRUZ R C D, REINSHAGEN J, OBERACKER R, SEGADAES A M, HOFFMANN M J. Electrical Conductivity and stability of concentrated aqueous alumina suspensions [J]. Journal of Colloid and Interface Science, 2005, 286: 579–588.

    Article  Google Scholar 

  37. WONG K F V, KURMA T. Transport properties of alumina nanofluids [J]. Nanotechnology, 2008, 19: 34570.

    Google Scholar 

  38. KONAKANCHI H, VAJJH R, MISRA D, DAS D. Electrical conductivity measurements of nanofluids and development of new correlations [J]. J Nanoscience and Nanotechnology, 2011, 11: 6788–6795.

    Article  Google Scholar 

  39. TENG T P, CHENG C M, PAI F Y. Preparation and characterization of carbon nanofluid by a plasma arc nanoparticles synthesis system [J]. Research Letters, 2011, 6: 293.

    Google Scholar 

  40. SIKDAR S. Investigation of electrical conductivity of titanium dioxide nanofluids [J]. International Journal of Nanoparticles, 2011, 4(4): 336–350.

    Article  Google Scholar 

  41. GLORY J, BONETTI M, HELEZEN M, HERMITE M, REYNAUD C. Thermal and electrical conductivities of water-based nanofluids prepared with long multiwalled carbon nanotubes [J]. Journal of Applied Physics, 2008, 103: 1–7.

    Article  Google Scholar 

  42. MEHREZ Z, CAFSI A E, BELGHITH A, QUERE P L. MHD effects on heat transfer and entropy generation of nanofluid flow in an open cavity [J]. J Magnetism Magnetic Mater, 2015, 364: 214–224.

    Article  Google Scholar 

  43. VAJJHA R S, DAS D K. Experimental determination of thermal conductivity of three nanofluids and development of new correlations [J]. Int J Heat Mass Transfer, 2009, 52: 4675–4682.

    Article  MATH  Google Scholar 

  44. KOO J, KLEINSTREUER C. Laminar nanofluid flow in microheat-sinks [J]. Int J Heat Mass Transfer, 2005, 48: 2652–2661.

    Article  MATH  Google Scholar 

  45. ACHARYA S, DIXIT S, HOU G. Laminar mixed convection in a vertical channel with a backstep: A benchmark study [J]. ASME HTD, 1993, 258: 11–20.

    Google Scholar 

  46. LIN J, ARMALY B, CHEN T. Mixed convection in buoyancy-assisted vertical backward-facing step flows [J]. International Journal of Heat and Mass Transfer, 1990, 33: 2121–2132.

    Article  Google Scholar 

  47. DYNE B, PEPPER D, BRUECKNER F. Mixed convection in a vertical channel with a backward-facing step [J]. ASME HTD, 1993, 258: 49–56.

    Google Scholar 

  48. EL-REFAEE M, EL-SAYED M, AL-NAJEM N, MEGAHID I. Steady-state solutions of buoyancy-assisted internal flows using a fast false implicit transient scheme (fits) [J]. International Journal of Numerical Methods Heat Fluid Flow, 1996, 6: 3–23.

    Article  MathSciNet  MATH  Google Scholar 

  49. COCHRAN R, HORSTMAN R, SUN Y, EMERY A. Benchmark solution for a vertical buoyancy-assisted laminar backward-facing step flow using finite element, finite volume and finite difference methods [J]. ASME HTD, 1993, 258: 37–47.

    Google Scholar 

  50. RUDRAIAH N, BARRON R, VENKATACHALAPPA M, SUBBARAYA C. Effect of a magnetic field on free convection in a rectangular enclosure [J]. Int J Eng Sci, 1995, 33: 1075–1084.

    Article  MATH  Google Scholar 

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Authors and Affiliations

  1. Department of Mechanical Engineering, Celal Bayar University, 45140, Manisa, Turkey

    Fatih Selimefendigil & Seda Özcan Çoban

  2. Department of Mechanical Engineering, Technology Faculty, Fırat University, 23119, Elazığ, Turkey

    Hakan F. Öztop

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  1. Fatih Selimefendigil
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Correspondence to Fatih Selimefendigil.

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Selimefendigil, F., Özcan Çoban, S. & Öztop, H.F. Electrical conductivity effect on MHD mixed convection of nanofluid flow over a backward-facing step. J. Cent. South Univ. 26, 1133–1145 (2019). https://doi.org/10.1007/s11771-019-4076-9

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