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Research Papers

Assisting and Opposing Combined Convective Heat Transfer and Nanofluids Flows Over a Vertical Forward Facing Step

[+] Author and Article Information
H. A. Mohammed

Mem. ASME
Department of Thermofluids,
Faculty of Mechanical Engineering,
Universiti Teknologi Malaysia,
UTM Skudai,
Johor Bahru 81310, Malaysia
e-mail: Hussein.dash@yahoo.com

Omar A. Hussein

Department of Mechanical Engineering,
College of Engineering,
Tikrit University,
PO Box 42,
Tikrit, Salahuddin, Iraq

1Corresponding author.

Manuscript received February 9, 2014; final manuscript received July 4, 2014; published online August 6, 2014. Assoc. Editor: Calvin Li.

J. Nanotechnol. Eng. Med 5(1), 010903 (Aug 06, 2014) (13 pages) Paper No: NANO-14-1010; doi: 10.1115/1.4028009 History: Received February 09, 2014; Revised July 04, 2014

Numerical simulations of two-dimensional (2D) laminar mixed convection heat transfer and nanofluids flows over forward facing step (FFS) in a vertical channel are numerically carried out. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The wall downstream of the step was maintained at a uniform wall heat flux, while the straight wall that forms the other side of the channel was maintained at constant temperature equivalent to the inlet fluid temperature. The upstream walls for the FFS were considered as adiabatic surfaces. The buoyancy assisting and buoyancy opposing flow conditions are investigated. Four different types of nanoparticles, Al2O3, CuO, SiO2, and ZnO with different volumes' fractions in the range of 1–4% and different nanoparticle diameters in the range of 25–80 nm, are dispersed in the base fluid (water) are used. In this study, several parameters, such as different Reynolds numbers in the range of 100 < Re < 900, and different heat fluxes in the range of 500 ≤ qw ≤ 4500 W/m2, and different step heights in the range of 3 ≤ S ≤ 5.8 mm, are investigated to identify their effects on the heat transfer and fluid flow characteristics. The numerical results indicate that the nanofluid with SiO2 has the highest Nusselt number compared with other nanofluids. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase, and it decreases as the nanoparticle diameter increases. This study has revealed that the assisting flow has higher Nusselt number than opposing flow.

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References

Luzhanskiy, B. Y., and Solntsev, V., 1972, “An Experimental Study of Flow in the Separation Zones of a Turbulent Boundary Layer Upstream of a Two-Dimensional Step,” Akad Nauk Sssr Mekh zhidk Gaza.
Baker, S., 1977, “Regions of Recirculating Flow Associated With Two-Dimensional Steps,” Ph.D. thesis, University of Surrey, Surrey, UK.
Daungthongsuk, W., and Wongwises, S., 2007, “A Critical Review of Convective Heat Transfer of Nanofluids,” Renewable Sustainable Energy Rev., 11(5), pp. 797–817. [CrossRef]
Wang, X. Q., and Mujumdar, A. S., 2007, “Heat Transfer Characteristics of Nanofluids: A Review,” Int. J. Therm. Sci., 46(1), pp. 1–19. [CrossRef]
Al-aswadi, A. A., Mohammed, H. A., Shuaib, N. H., and Campo, A., 2010, “Laminar Forced Convection Flow Over a Backward Facing Step Using Nanofluids,” Int. Commun. Heat Mass Transfer, 37(8), pp. 950–957. [CrossRef]
Mohammed, H. A., Al-aswadi, A. A., Yusoff, M. Z., and Saidur, R., 2012, “Buoyancy-Assisted Mixed Convective Flows Over Backward Facing Step in a Vertical Duct Using Various Nanofluids,” Thermophys. Aeromech., 42(1), pp. 33–60. [CrossRef]
Mohammed, H. A., Al-aswadi, A. A., Shuaib, N. H., and Saidur, R., 2011, “Convective Heat Transfer and Fluid Flow Study Over a Step Using Nanofluids: A Review,” Renewable Sustainable Energy Rev., 15(6), pp. 2921–2939. [CrossRef]
Lin, J. T., Armaly, B. F., and Chen, T. S., 1991, “Mixed Convection Heat Transfer in Inclined Backward-Facing Step Flows,” Int. J. Heat Mass Transfer, 34, pp. 1568–1571. [CrossRef]
Hong, B., Armaly, B. F., and Chen, T. S., 1993, “Laminar Mixed Convection in a Duct With a Backward-Facing Step: The Effects of Inclination Angle and Prandtl Number,” Int. J. Heat Mass Transfer, 36(12), pp. 3059–3067. [CrossRef]
Abu-Mulaweh, H. I., Armaly, B. F., and Chen, T. S., 1995, “Laminar Natural Convection Flow Over a Vertical Backward-Facing Step,” ASME J. Heat Transfer, 117, pp. 895–901. [CrossRef]
Abu-Mulaweh, H. I., Armaly, B. F., and Chen, T. S., 2001, “Turbulent Mixed-Convection Flow Over a Backward-Facing Step,” Int. J. Heat Mass Transfer, 44(14), pp. 2661–2669. [CrossRef]
Wilhelm, D., and Kleiser, L., 2002, “Application of a Spectral Element Method to Two-Dimensional Forward-Facing Step Flow,” J. Sci. Comput., 17(1–4), pp. 619–627. [CrossRef]
Largeau, J., and Moriniere, V., 2007, “Wall Pressure Fluctuations and Topology in Separated Flows Over a Forward-Facing Step,” Exp. Fluids, 42(1), pp. 21–40. [CrossRef]
Gandjalikhan Nassab, S., Moosavi, R., and Hosseini Sarvari, S., 2009, “Turbulent Forced Convection Flow Adjacent to Inclined Forward Step in a Duct,” Int. J. Therm. Sci., 48(7), pp. 1319–1326. [CrossRef]
Barbosa Saldana, J. G., Anand, N. K., and Sarin, V., 2005, “Numerical Simulation for Mixed Convective Flow Over a Three-Dimensional Horizontal Backward Facing Step,” ASME Heat Transfer/Fluids Engineering Summer Conference, Charlotte, NC, July 11–15, pp. 1031–1042. [CrossRef]
Barbosa Saldana, J. G., and Anand, N., 2007, “Flow Over a Three-Dimensional Horizontal Forward-Facing Step,” Numerical Heat Transfer, Part A: Applications, 53(1), pp. 1–17. [CrossRef]
Abu-Mulaweh, H., 2003, “A Review of Research on Laminar Mixed Convection Flow Over Backward-and Forward-Facing Steps,” Int. J. Therm. Sci., 42(9), pp. 897–909. [CrossRef]
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]
Asseban, A., Lallemand, M., Saulnier, J. B., Fomin, N., Lavinskaja, E., Merzkirch, W., and Vitkin, D., 2000, “Digital Speckle Photography and Speckle Tomography in Heat Transfer Studies,” Opt. Laser Technol., 32(7–8), pp. 583–592. [CrossRef]
Abu-Mulaweh, H. I., Armaly, B. F., Chen, T. S., and Hong, B., 1994, “Mixed Convection Adjacent to a Vertical Forward-Facing Step,” Proceedings of the 10th International Heat Transfer Conference, 5, pp. 423–428.
Abu-Mulaweh, H. I., Armaly, B. F., and Chen, T. S., 1993, “Measurements of Laminar Mixed Convection Flow Over a Horizontal Forward-Facing Step,” J. Thermophys. Heat Transfer, 7(4), pp. 569–573. [CrossRef]
Abu-Mulaweh, H. I., Armaly, B. F., and Chen, T. S., 1993, “Measurements of Laminar Mixed Convection in a Boundary-Layer Flow Over Horizontal and Inclined Backward-Facing Steps,” Int. J. Heat Mass Transfer, 36(7), pp. 1883–1895. [CrossRef]
Abu-Mulaweh, H. I., Chen, T. S., and Armaly, B. F., 2002, “Turbulent Mixed-Convection Flow Over a Backward-Facing Step—The Effect of Step Heights,” Int. J. Heat Fluid Flow, 23(6), pp. 758–765. [CrossRef]
Abu-Mulaweh, H. I., Armaly, B. F., and Chen, T. S., 2003, “Measurements of Turbulent Mixed Convection Flow Over a Vertical Forward-Facing Step,” ASME Proceedings of the Summer Heat Transfer Conference, Las Vegas, NV, July 21–23, pp. 755–763, Paper No. HT2003-47088.
Abu-Nada, E., 2008, “Application of Nanofluids for Neat Transfer Enhancement of Separated Flows Encountered in a Backward Facing Step,” Int. J. Heat Fluid Flow, 29(1) pp. 242–249.
Bianco, V., Chiacchio, F., Manca, O., and Nardini, S., 2009, “Numerical Investigation of Nanofluids Forced Convection in Circular Tubes,” Appl. Therm. Eng., 29(17), pp. 3632–3642. [CrossRef]
Patankar, S. V., 1980, “Numerical Heat Transfer and Fluid Flow,” Hemisphere Publishing Corporation, Washington, DC.
Ghasemi, B., and Aminossadati, S. M., 2010, “Brownian Motion of Nanoparticles in a Triangular Enclosure With Natural Convection,” Int. J. Therm. Sci., 49(6), pp. 931–940. [CrossRef]
Vajjha, R. S., and Das, D. K., 2009, “Experimental Determination of Thermal Conductivity of Three Nanofluids and Development of New Correlations,” Int. J. Heat Mass Transfer, 52(21–22), pp. 4675–4682. [CrossRef]
Corcione, M., 2010, “Heat Transfer Features of Buoyancy-Driven Nanofluids Inside Rectangular Enclosures Differentially Heated at the Sidewalls,” Int. J. Therm. Sci., 49(9), pp. 1536–1546. [CrossRef]
Kherbeet, A., Sh., Mohammed, H. A., and Salman, B. H., 2012, “The Effect of Nanofluids on Mixed Convection Flow Over Microscale Backward-Facing Step,” Int. J. Heat Mass Transfer, 55(21–22), pp. 5870–5881. [CrossRef]
Heshmati, A., Mohammed, H. A., and Darus, A. N., 2014, “Mixed Convection Heat Transfer of Nanofluids Over Backward Facing Step Having a Slotted Baffle,” Appl. Math. Comput., 240, pp. 368–386. [CrossRef]

Figures

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Fig. 1

Schematic diagram for 2D FFS in a vertical channel

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Fig. 2

Comparison of velocity distribution with the results of Al-aswadi et al. [5] in the recirculation region for S = 4.8 mm, and ER = 2 at Re = 175 for Al2O3 at different X/s, (a) 1.04, (b) 1.92, (c) 2.6, and (d) 32.8

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Fig. 3

Comparison of velocity distribution with the results of Al-aswadi et al. [5] in the recirculation region for S = 4.8 mm, and ER = 2 at Re = 175 for CuO at different X/s (a) 1.04, (b) 1.92, (c) 2.6, and (d) 32.8

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Fig. 4

Comparison of skin friction coefficient of SiO2 nanofluids for different Reynolds numbers (a) Re = 50 and (b) Re = 175 at the bottom wall downstream of the step

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Fig. 5

Comparison of the present results with the results of Hong et al. [9] (S = 4.8 mm, and ER = 2) for Re = 100 and qw = 200 W/m2 (X = 3) at 0 deg angle (a) velocity distribution and (b) Nusselt number

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Fig. 6

The effect of nanofluids parameters along the downstream wall at Re = 300, qw = 500 W/m2, ∅ = 4%, and dp = 25 nm for (a) different nanoparticle types, (b) different volume fractions, and (c) different nanoparticle diameters

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Fig. 7

Velocity distributions of SiO2 nanofluid with ∅ = 4% and dp = 25 nm at different Reynolds numbers for qw = 500 W/m2 at (a) x/S = 0, (b) x/S = 1.8, (c) x/S = 12.82, and (d) exit

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Fig. 11

The effect of step heights of SiO2 nanofluid with ∅ = 4%, dp = 25, and Re = 500 along the downstream wall on (a) Nusselt number, (b) isotherms at S = 5.8 mm, (c) isotherms at S = 4.8 mm, and (d) isotherms at S = 3 mm

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Fig. 12

The effect of assisting and opposing flows on Nusselt number of SiO2 nanofluid with ∅ = 4% and dp = 25 nm at qw = 500 W/m2 and Re = 100 along the downstream wall of FFS

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Fig. 8

The effect of Reynolds number of SiO2 nanofluid with ∅ = 4%, dp = 25, and qw = 500 W/m2 along the downstream wall (a) Nusselt number and (b) skin friction coefficient

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Fig. 9

Velocity distributions of SiO2 nanofluid with φ = 4% and dp = 25 nm at different heat fluxes for Re = 100 at (a) x/S = 0, (b) x/S = 1.8, (c) x/S = 12.82, and (d) exit

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Fig. 10

The effect of heat flux of SiO2 nanofluid with ∅ = 4% and dp = 25 at Re = 100 along the downstream wall (a) skin friction coefficient and (b) Nusselt number

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