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Research Papers

Laminar Convective Nanofluid Flow Over a Backward-Facing Step With an Elastic Bottom Wall

[+] Author and Article Information
Fatih Selimefendigil

Department of Mechanical Engineering,
Celal Bayar University,
Manisa 45140, Turkey
e-mail: fatih.selimefendigil@cbu.edu.tr

Hakan F. Öztop

Professor
Technology Faculty,
Department of Mechanical Engineering,
Fırat University,
Elaziğ 23119, Turkey
e-mail: hfoztop1@gmail.com

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS. Manuscript received July 4, 2017; final manuscript received October 21, 2017; published online March 30, 2018. Assoc. Editor: Nesrin Ozalp.

J. Thermal Sci. Eng. Appl 10(4), 041003 (Mar 30, 2018) (7 pages) Paper No: TSEA-17-1229; doi: 10.1115/1.4038738 History: Received July 04, 2017; Revised October 21, 2017

In the present study, laminar forced convective nanofluid flow over a backward-facing step was numerically investigated. The bottom wall downstream of the step was flexible, and finite element method was used to solve the governing equations. The numerical simulation was performed for a range of Reynolds number (between 25 and 250), elastic modulus of the flexible wall (between 104 and 106), and solid particle volume fraction (between 0 and 0.035). It was observed that the flexibility of the bottom wall results in the variation of the fluid flow and heat transfer characteristics for the backward-facing step problem. As the value of Reynolds number and solid particle volume fraction enhances, local and average heat transfer rates increase. At the highest value of Reynolds number, heat transfer rate is higher for the case with the wall having lowest value of elastic modulus whereas the situation is reversed for other value of Reynolds number. Average Nusselt number reduces by about 9.21% and increases by about 6.1% for the flexible wall with the lowest elastic modulus as compared to a rigid bottom wall for Reynolds number of 25 and 250. Adding nano-additives to the base fluid results in higher heat transfer enhancements. Average heat transfer rates enhance by about 35.72% and 35.32% at the highest solid particle volume fraction as compared to nanofluid with solid volume fraction of 0.01 for the case with wall at the lowest and highest elastic modulus. A polynomial type correlation for the average Nusselt number along the flexible hot wall was proposed, which is dependent on the elastic modulus and solid particle volume fraction. The results of this study are useful for many thermal engineering problems where flow separation and reattachment coupled with heat transfer occur. Control of convective heat transfer for such configurations with wall flexibility and nanoparticle inclusion to the base fluid was aimed in this study to find the effects of various pertinent parameters for heat transfer enhancement.

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References

Stuer, H. , Gyr, A. , and Kinzelbach, W. , 1999, “ Laminar Separation on a Forward Facing Step,” Eur. J. Mech. B, 18(4), pp. 675–692. [CrossRef]
Abu-Mulaweh, H. , 2005, “ Turbulent Mixed Convection Flow Over a Forward-Facing Step—The Effect of Step Heights,” Int. J. Therm. Sci., 44(2), pp. 155–162. [CrossRef]
Selimefendigil, F. , and Oztop, H. F. , 2014, “ Control of Laminar Pulsating Flow and Heat Transfer in Backward-Facing Step by Using a Square Obstacle,” ASME J. Heat Transfer, 136(8), p. 081701. [CrossRef]
Selimefendigil, F. , and Oztop, H. F. , 2013, “ Numerical Analysis of Laminar Pulsating Flow at a Backward Facing Step With an Upper Wall Mounted Adiabatic Thin Fin,” Comput. Fluids, 88, pp. 93–107. [CrossRef]
Armaly, B. F. , Durst, F. , Pereier, J. C. F. , and Schonung, B. , 1983, “ Experimental and Theoretical Investigation of Backward-Facing Step Flow,” J. Fluid Mech., 127, pp. 473–496. [CrossRef]
Sherry, M. , LoJacono, D. , and Sheridan, J. , 2010, “ An Experimental Investigation of the Recirculation Zone Formed Downstream of a Forward Facing Step,” J. Wind Eng. Ind. Aerodyn., 98(12), pp. 888–894. [CrossRef]
Barkley, D. , Gomes, M. G. M. , and Henderson, R. D. , 2002, “ Three-Dimensional Instability in Flow Over a Backward-Facing Step,” J. Fluid Mech., 473, pp. 167–190. [CrossRef]
Erturk, E. , 2008, “ Numerical Solutions of 2-D Steady Incompressible Flow Over a Backward-Facing Step—Part 1: High Reynolds Number Solutions,” Comput. Fluids, 37(6), pp. 633–655. [CrossRef]
Barbosa-Saldana, J. G. , and Anand, N. K. , 2007, “ Flow Over a Three-Dimensional Horizontal Forward-Facing Step,” Numer. Heat Transfer, Part A, 53(1), pp. 1–17. [CrossRef]
Saldana, J. G. B. , Anand, N. K. , and Sarin, V. , 2005, “ Numerical Simulation of Mixed Convective Flow Over a Three-Dimensional Horizontal Backward Facing Step,” ASME J. Heat Transfer, 127(9), pp. 1027–1036. [CrossRef]
Iwai, H. , Nakabe, K. , and Suzuki, K. , 2000, “ Flow and Heat Transfer Characteristics of Backward-Facing Step Laminar Flow in a Rectangular Duct,” Int. J. Heat Mass Transfer, 43(3), pp. 457–471. [CrossRef]
Nie, J. , and Armaly, B. , 2004, “ Convection in Laminar Three-Dimensional Separated Flow,” Int. J. Heat Mass Transfer, 47(25), pp. 5407–5416. [CrossRef]
Batenko, S. R. , and Terekhov, V. I. , 2006, “ Friction and Heat Transfer in a Laminar Separated Flow behind a Rectangular Step With Porous Injection or Suction,” J. Appl. Mech. Tech. Phys., 47(1), pp. 12–21. [CrossRef]
Abu-Nada, E. , Al-Sarkhi, A. , Akash, B. , and Al-Hinti, I. , 2007, “ Heat Transfer and Fluid Flow Characteristics of Separated Flows Encountered in a Backward-Facing Step Under the Effect of Suction and Blowing,” ASME J. Heat Transfer, 129(11), pp. 1517–1528. [CrossRef]
Oztop, H. F. , Mushatet, K. S. , and Yılmaz, I. , 2012, “ Analysis of Turbulent Flow and Heat Transfer Over a Double Forward Facing Step With Obstacles,” Int. Commun. Heat Mass Transfer, 39(9), pp. 1395–1403. [CrossRef]
Selimefendigil, F. , and Oztop, H. F. , 2017, “ Conjugate Natural Convection in a Nanofluid Filled Partitioned Horizontal Annulus Formed by Two Isothermal Cylinder Surfaces Under Magnetic Field,” Int. J. Heat Mass Transfer, 108(Pt. A), pp. 156–171. [CrossRef]
Abu-Nada, E. , 2008, “ Application of Nanofluids for Heat Transfer Enhancement of Separated Flows Encountered in a Backward Facing Step,” Int. J. Heat Fluid Flow, 29(1), pp. 242–249. [CrossRef]
Selimefendigil, F. , and Oztop, H. F. , 2013, “ Identification of Forced Convection in Pulsating Flow at a Backward Facing Step With a Stationary Cylinder Subjected to Nanofluid,” Int. Commun. Heat Mass Transfer, 45, pp. 111–121.
Amiri, A. , Arzani, H. K. , Kazi, S. , Chew, B. , and Badarudin, A. , 2016, “ Backward-Facing Step Heat Transfer of the Turbulent Regime for Functionalized Graphene Nanoplatelets Based Water-Ethylene Glycol Nanofluids,” Int. J. Heat Mass Transfer, 97, pp. 538–546. [CrossRef]
Mohammed, K. A. , Talib, A. A. , Nuraini, A. , and Ahmed, K. , 2017, “ Review of Forced Convection Nanofluids Through Corrugated Facing Step,” Renewable Sustainable Energy Rev., 75, pp. 234–241. [CrossRef]
Khanafer, K. , 2014, “ Comparison of Flow and Heat Transfer Characteristics in a Lid-Driven Cavity Between Flexible and Modified Geometry of a Heated Bottom Wall,” Int. J. Heat Mass Transfer, 78, pp. 1032–1041. [CrossRef]
Al-Amiri, A. , and Khanafer, K. , 2011, “ Fluid-Structure Interaction Analysis of Mixed Convection Heat Transfer in a Lid-Driven Cavity With a Flexible Bottom Wall,” Int. J. Heat Mass Transfer, 54(17–18), pp. 3826–3836. [CrossRef]
Selimefendigil, F. , Oztop, H. F. , and Chamkha, A. J. , 2017, “ Fluid–Structure-Magnetic Field Interaction in a Nanofluid Filled Lid-Driven Cavity With Flexible Side Wall,” Eur. J. Mech. B, 61(Pt. 1), pp. 77–85. [CrossRef]
Selimefendigil, F. , and Oztop, H. F. , 2017, “ Mixed Convection in a Partially Heated Triangular Cavity Filled With Nanofluid Having a Partially Flexible Wall and Internal Heat Generation,” J. Taiwan Inst. Chem. Eng., 70, pp. 168–178. [CrossRef]
Ghalambaz, M. , Jamesahar, E. , Ismael, M. A. , and Chamkha, A. J. , 2017, “ Fluid-Structure Interaction Study of Natural Convection Heat Transfer Over a Flexible Oscillating Fin in a Square Cavity,” Int. J. Therm. Sci., 111, pp. 256–273. [CrossRef]
Chon, C. H. , Kihm, K. D. , Lee, S. P. , and Choi, S. U. , 2005, “ Empirical Correlation Finding the Role of Temperature and Particle Size for Nanofluid (Al2O3) Thermal Conductivity Enhancement,” Appl. Phys. Lett., 87(15), p. 153107. [CrossRef]
Abu-Nada, E. , 2009, “ Effects of Variable Viscosity and Thermal Conductivity of Al2O3-Water Nanofluid on Heat Transfer Enhancement in Natural Convection,” Int. J. Heat Fluid Flow, 30(4), pp. 679–690. [CrossRef]
Brinkman, H. , 1952, “ The Viscosity of Concentrated Suspensions and Solutions,” J. Chem. Phys., 20(4), pp. 571–581. [CrossRef]
Mahmoudi, A. H. , Pop, I. , and Shahi, M. , 2012, “ Effect of Magnetic Field on Natural Convection in a Triangular Enclosure Filled With Nanofluid,” Int. J. Therm. Sci., 59, pp. 126–140. [CrossRef]
Acharya, S. , Dixit, G. , and Hou, Q. , 1993, “ Laminar Mixed Convection in a Vertical Channel With a Backstep: A Benchmark Study,” ASME Winter Annual Meeting, New Orleans, LA, Nov. 28–Dec. 3, pp. 11–20.
Lin, J. , Armaly, B. , and Chen, T. , 1990, “ Mixed Convection in Buoyancy-Assisted Vertical Backward-Facing Step Flows,” Int. J. Heat Mass Transfer, 33(10), pp. 2121–2132. [CrossRef]
Cochran, R. , Horstman, R. , Sun, Y. , and Emery, A. , 1993, “ Benchmark Solution for a Vertical Buoyancy-Assisted Laminar Backward-Facing Step Flow Using Finite Element, Finite Volume and Finite Difference Methods,” ASME Winter Annual Meeting, New Orleans, LA, Nov. 28–Dec. 3, pp. 37–47.
El-Refaee, M. , El-Sayed, M. , Al-Najem, N. , and Megahid, I. , 1996, “ Steady-State Solutions of Buoyancy-Assisted Internal Flows Using a Fast False Implicit Transient Scheme (Fits),” Int. J. Numer. Methods Heat Fluid Flow, 6, pp. 3–23. [CrossRef]
Khandelwal, V. , Dhiman, A. , and Baranyi, L. , 2015, “ Laminar Flow of Non-Newtonian Shear-Thinning Fluids in a T-Channel,” Comput. Fluids, 108, pp. 79–91. [CrossRef]
Chiang, T. P. , and Sheu, T. W. H. , 1999, “ A Numerical Revisit of Backward-Facing Step Flow Problem,” Phys. Fluids, 11(4), pp. 862–874. [CrossRef]
Williams, P. T. , and Baker, A. J. , 1997, “ Numerical Simulations of Laminar Flow Over a 3D Backward-Facing Step,” Int. J. Numer. Methods Fluids, 24(11), pp. 1159–1183. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Physical model with boundary conditions

Grahic Jump Location
Fig. 2

Effects of varying Reynolds number on the distribution of streamlines and isotherms (E = 104, ϕ = 0.02): (a) Re = 25, (b) Re = 100, (c) Re = 250, (d) Re = 25, (e) Re = 100, and (f) Re = 250

Grahic Jump Location
Fig. 3

Streamline and isotherm distributions for various elastic modulus of the flexible bottom wall (Re = 200, ϕ = 0.02): (a) E = 104, (b) E = 105, (c) E = 106, (d) E = 104, (e) E = 105, and (f) E = 106

Grahic Jump Location
Fig. 4

Distribution of local Nusselt number along the hot wall for different elastic modulus and Reynolds number (ϕ = 0.02): (a) E = 104, (b) E = 105, and (c) E = 106

Grahic Jump Location
Fig. 5

Average Nusselt number versus Reynolds number for various elastic modulus of flexible wall (ϕ = 0.02)

Grahic Jump Location
Fig. 6

Effects of solid particle volume fraction on the distribution of local Nusselt number for various elastic modulus of flexible wall (Re = 200): (a) E = 104, (b) E = 105, and (c) E = 106

Grahic Jump Location
Fig. 7

Average Nusselt number versus solid particle volume fraction for various elastic modulus of flexible wall (Re = 200)

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