Numerical investigation into flow and mixed convective heat transfer of non-Newtonian impinging slot jets

Document Type : Research Note

Authors

Mechanical Engineering Department, Azarbaijan Shahid Madani University, Tabriz, P.O. box 53714-161, Iran

Abstract

Mixed convection heat transfer of non-Newtonian impinging slot jets was investigated numerically. The simulation was performed using a temperature dependent power-law viscosity model. The results showed that for high Richardson numbers, a recirculation zone is created in the vicinity of impingement wall which prevents the jet stream from penetration into near wall region and decreases the Nusselt number around the stagnation point. The effects of jet-to-plate spacing, inlet Peclet number and the jet inlet width on the flow structure and heat transfer characteristics of impinging jet were studied using the numerical results. By decreasing jet-to-plate spacing and jet inlet width and increasing inlet Peclet number, the flow reversal in the vicinity of heated wall was disappeared and the local Nusselt number increases as a result of deeper penetration of jet stream the near wall region. Furthermore, the results indicated that the maximum local and average Nusselt numbers belong to the shear-thinning jets with minimum inlet width and the minimum jet-to-plate spacing.

Keywords

Main Subjects


References
1. Lin, Z.H., Chou, Y.J., and Hung, Y.H. \Heat transfer
behaviors of a con ned slot jet impingement", Int. J.
Heat Mass Trans., 40, pp. 1095-1107 (1977).
2. Shi, Y.L., Rar, M.B., and Mujumdar, A.S. \E ect of
Prandtl number on impinging jet heat transfer under a
semi-con ned laminar slot jet", Int. Comm. Heat Mass
Trans., 30, pp. 455-464 (2003).
3. Lee, H.G., Yoon, H.S., and Ha. M.Y. \A numerical
investigation on the
uid
ow and heat transfer in the
con ned impinging slot jet in the low Reynolds number
region for di erent channel heights", Int. J. Heat Mass
Trans., 51, pp. 4055-4068 (2008).
4. Chiriac, V.C. and Ortega, A.\A numerical study of
the unsteady
ow and heat transfer in a transitional
con ned slot jet impinging on an isothermal surface",
Int. J. Heat Mass Trans., 45, pp. 1237-1248 (2002).
5. Cavadas, A.S., Pinho, F.T., and Campos, J.B.L.M.
\Laminar
ow eld in a viscous liquid impinging jet
con ned by inclined plane walls", Int. J. Therm. Sci.,
59, pp. 95-110 (2012).
6. Aldabbagh, L.B.Y. and Mohammad, A.A. \Mixed
convection in an impinging laminar single square jet",
ASME J. Heat Trans., 131, pp. 022201-1-7 (2009).
7. Poh, H.J. and Kumar, K. \Heat transfer from a
laminar impinging jet of a power law
uid", Int.
Comm. Heat Mass Trans., 31, pp. 241-249 (2004).
8. Chatterjee, A., Dhingra, S.C., and Kapur, S. \Laminar
impinging jet heat transfer with a purely viscous
inelastic
uid", Num. Heat Trans. A., 42, pp. 193-213
(2002).
9. Cavadas, A.S., Pinho, F.T., and Campos, J.B.L.M.
\Laminar non-Newtonian impinging jet
ow con-
ned by sloping plane walls", J. Non-Newton. Fluid.,
169(170), pp. 1-14 (2012).
10. Wang, Ch.Ch. and Chen, Ch.K. \Mixed convection
boundary layer
ow of non-Newtonian
uid along
vertical wavy plates", Int. J. Heat Fluid Fl., 23, pp.
831-839 (2002).
11. Lee, D.H., Park, H.J., and Ligrani, Ph. \Milliscale
con ned impinging slot jets: Laminar heat transfer
characteristics for an isothermal
at plate", Int. J.
Heat Mass Trans., 55, pp. 2249-2260 (2012).
12. Kumari, M., Pop, I., and Takhar, H.S. \Freeconvection
boundary-layer
ow of a non- Newtonian

uid along a vertical wavy surface", Int. J. Heat Fluid
Fl., 18, pp. 625-631 (1997).
13. Sivasamy, A., Selladurai, V., and Rajesh Kanna, P.
\Jet impingement cooling of a constant heat
ux
horizontal surface in a con ned porous medium: Mixed
convection regime", Int. J. Heat Mass Trans., 53, pp.
5847-5855 (2010).
14. Ostwald, W. \About the velocity function of the
viscosity of disperse systems I" [Journal Ueber die
Geschwindigkeitsfunktion der Viskositat disperser Systeme
I], Kolloid-Zeitschrift, 36, pp. 99-117 (1925).
15. De Waele, A. \Viscometry and Plastometry", J. Oil &
Col. Chem. Assoc., 6, pp. 33-69 (1923).
16. Chhabra, R.P. and Richardson, J.F., Non-Newtonian
Flow and Applied Rheology, Engineering Applications,
2nd Edn., Butterworth-Heinemann/IChemE,
UK (2008).
17. Patankar, S.V., Numerical Heat Transfer and Fluid
Flow, 1st. Edn., Hemisphere, USA (1980).
R. Gharraei et al./Scientia Iranica, Transactions B: Mechanical Engineering 25 (2018) 2208{2217 2217
18. Srisamran, Ch. and Devahastin, S. \Numerical simulation
of
ow and mixing behavior of impinging streams
of shear-thinning
uids", Chem. Eng. Sci., 61, pp.
4884-4892 (2006).
19. Gharraei, R., Vejdani, A., Islami, S.B., and Davani.D.,
A.A. \Numerical investigation on the
uid
ow and
heat transfer of the non-Newtonian multiple impinging
jets", Int. J. Therm. Sci., 104, pp. 257-265 (2016).