MIXED CONVECTION IN AN ECCENTRIC ANNULUS FILLED BY COPPER NANOFLUID

Abstract

A numerical study of mixed convection flow and heat transfer of Copper (Cu)-water nanofluid inside an eccentric horizontal annulus is presented. The inner and outer cylinders are kept at constant temperatures as Th and Tc, respectively. The inner cylinder rotates to generate the forced convection effect. The numerical work was carried out using an in-house CFD code written in FORTRAN. Different scenarios were explored to explain the effects of different parameters on the studied problem. These parameters are Richardson number, eccentricity ratio, and solid volume fraction. The range of the Richardson number Ri, solid volume fraction of the nanoparticles ζ, and the eccentricity ratio ε, are 0.01 ≤ Ri ≤ 100 (natural convection), 0 ≤ ζ ≤ 0.05, 0 ≤ ε ≤ 0.9 respectively. All results were performed with thermal Grashof number Gr, and radius ratio Rr, equaled to 104 and 2, respectively. The effects of eccentricity, nanoparticles volume fraction, and Richardson number on the average Nusselt number, streamlines and isotherms were investigated. Results were discussed, and were found to be in good agreement with previous works. It was also found that, the eccentricity has a positive remarkable effect on the average Nusselt number, while the effect of nanoparticles concentration was more pronounced at mixed convection region (Ri=1).

Dates

  • Submission Date2014-08-02
  • Revision Date2014-10-19
  • Acceptance Date2014-11-01
  • Online Date2014-11-08

DOI Reference

10.2298/TSCI140802128E

References

  1. Mahmoodi, M., Arani, A., Sebdani, S., Nazari, S., Akbari, M., Free convection of a nanofluid in a square cavity with a heat source on the bottom wall and partially cooled from sides, thermal science, 18 (2014) pp. s283-s300
  2. Mahmoodi, M., Mixed convection inside nanofluid filled rectangular enclosures with moving bottom wall, thermal science, 15 (2011) pp. 889-903
  3. Deng, Q., Fluid flow and heat transfer characteristics of natural convection in square cavities due to discrete source sink pairs, Int. J. Heat Mass Transfer, 51 (2008) pp. 5949-5957
  4. Mohamad, A., Kuzmin, A., A critical evaluation of force term in lattice Boltzmann method, natural convection problem, Int. J. Heat Mass Transfer, 53 (2010) pp. 990-996
  5. Ghaddar, N., Natural convection heat transfer between a uniformly heated cylindrical element and its rectangular enclosure, Int. J. Heat Mass Transfer, 35 (1992) pp. 2327-2334
  6. Holzbecher, M., Steiff, A., Laminar and turbulent free convection in vertical cylinders with internal heat generation, Int. J. Heat Mass Transfer, 38 (1995) PP. 2893-2903
  7. Kao, P., Yang, R., Simulating oscillatory flows in Rayleigh-Bénard convection using the lattice Boltzmann method, Int. J. Heat Mass Transfer, 50 (2007) PP. 3315-3328
  8. Zhou, Y., Zhang, R., Staroselsky, I., Chen, H., Numerical simulation of laminar and turbulent buoyancy-driven flows using a lattice Boltzmann based algorithm, Int. J. Heat Mass Transfer, 47 (2004) PP.4869-4879
  9. Bau, H., Thermal convection in a horizontal eccentric annulus containing a saturated porous medium-an extended perturbation expansion, Int. J. Heat Mass Transfer, 27 (1984) PP.2277-2287
  10. Trisaksri, V., Wongwises, S., Critical review of heat transfer characteristics of nanofluids, Renewable and Sustainable Energy Reviews, 11 (2007) PP. 512-523
  11. Wang, X., Mujumdar, A., Heat transfer characteristics of nanofluids: a review, International Journal of Thermal Sciences, 46 (2007) PP 1-19
  12. Khanafer, K., Vafai, K., Lightstone, M., Buoyancy-driven heat transfer enhancement in a two-dimensional enclosure utilizing nanofluids, International Journal of Heat and Mass Transfer, 46 (2003) PP. 3639-3653
  13. Eastman, J., Choi, S., Li, S., Yu, W.,.J, L., Thompson, Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles, Appl. Phys. Lett., 78 (2001) PP. 718-720
  14. Xie, H., Lee, H., Youn, W., Choi, M., Nanofluids containing multiwalled carbon nanotubes and their enhanced thermal conductivities, J. Appl. Phys., 94 (2003) PP. 4967-4971
  15. Choi, S., Zhang, Z., Yu, W., Lockwood, F., Grulke, E., Anomalously thermal conductivity enhancement in nanotube suspensions, Appl. Phys. Lett., 79 (2001) PP. 2252-2254
  16. Abu-Nada, E., Effects of variable viscosity and thermal conductivity of CuO- water nanofluid on heat transfer enhancement in natural convection, mathematical model and simulation, ASME J. Heat Transfer, 132 (2010) PP. 1-9
  17. Abu-Nada, E., Masoud, Z., Hijazi, A., Natural convection heat transfer enhancement in horizontal concentric annuli using nanofluids, Int. Commun. Heat Mass Transfer, 35 (2008) PP. 657-665
  18. Habibi Matin, M., Pop, I., Natural convection flow and heat transfer in an eccentric annulus filled by Copper nanofluid, International Journal of Heat and Mass Transfer, 61 (2013) PP. 353-364
  19. Shariat, M., Akbarinia, A., Nezhad, A., Behzadmehr, A., Laur, R., Numerical study of two phase laminar mixed convection nanofluid in elliptic ducts, Applied Thermal Engineering, 31 (2011) PP. 2348-2359
  20. Mirmasoumi, S., Behzadmehr, A., Numerical study of laminar mixed convection of a nanofluid in a horizontal tube using two-phase mixture model, Applied Thermal Engineering, 28 (2008) PP.717-727
  21. Akbarinia, A., Behzadmehr, A., Numerical study of laminar mixed convection of a nanofluid in horizontal curved tubes, Applied Thermal Engineering, 27 (2007) PP. 1327-1337
  22. Kalteh, M., Abbassi, A., Saffar-Awal, M., Frijns, A., Darhuber, A., J. Harting, Experimental and numerical investigation of nanofluid forced convection inside a wide microchannel heat sink, Applied Thermal Engineering, 36 (2012) PP. 260-268
  23. Habibi Matin, M., Pop, I., Numerical Study of Mixed Convection Heat Transfer of a Nanofluid in an Eccentric Annulus, Numerical Heat Transfer, Part A: 65 (2014) PP. 84-105
  24. Patankar, S., Numerical Heat Transfer and Fluid Flow, (1980), McGraw-Hill, New York
  25. Teamah, M., El-Maghlany, W., Dawood, M., Numerical simulation of laminar forced convection in horizontal pipe partially or completely filled with porous material. International Journal of Thermal Sciences, 50 (2011) PP. 1512-1522
  26. Teamah, M., El-Maghlany, W., Augmentation of natural convective heat transfer in square cavity by utilizing nanofluids in the presence of magnetic field and uniform heat generation/absorption. International Journal of Thermal Sciences, 58 (2012) PP. 130-142
  27. Teamah, M., El-Maghlany, W., Numerical simulation of double-diffusive mixed convective flow in rectangular enclosure with insulated moving lid. International Journal of Thermal Sciences, 49 (2010) PP. 1625-1638
  28. Teamah, M., Sorour, M., El-Maghlany, W., Afifi, A., Numerical simulation of double diffusive laminar mixed convection in shallow inclined cavities with moving lid, Alexandria Engineering Journal, (2013) 52, PP. 227-239