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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/2430
Title: Two-dimensional unsteady forced convection heat transfer in power-law fluids from a cylinder
Authors: Patnana V.K.
Bharti, Ram Prakash
Chhabra R.P.
Published in: International Journal of Heat and Mass Transfer
Abstract: Forced convection heat transfer characteristics of a cylinder (maintained at a constant temperature) immersed in a streaming power-law fluids have been studied numerically in the two-dimensional (2-D), unsteady flow regime. The governing equations, namely, continuity, momentum and thermal energy, have been solved using a finite volume method based solver (FLUENT 6.3) over wide ranges of conditions (power law index, 0.4 ? n? 1.8; Reynolds number, 40 ? Re? 140; Prandtl number, 1 ? Pr? 100). In particular, extensive numerical results elucidating the influence of Reynolds number, Prandtl number and power-law index on the isotherm patterns, local and average Nusselt numbers and their evolution with time are discussed in detail. Over the ranges of conditions considered herein, the nature of flow is fully periodic in time. The heat transfer characteristics are seen to be influenced in an intricate manner by the value of the Reynolds number (Re), Prandtl number (Pr) and the power-law index (n). Depending upon the value of the power-law index (n), though the flow transits from being steady to unsteady somewhere in the range ~33 < Re< 50, the fully periodic behavior is seen only beyond the critical value of the Reynolds number (Re). As expected, the average Nusselt number increases with an increase in the values of Reynolds and/or Prandtl numbers, irrespective of the value of the flow behavior index. A strong influence of the power-law index on both local and time-averaged Nusselt numbers was observed. Broadly, all else being equal, shear-thinning behavior (n<1) promotes heat transfer whereas shear-thickening behavior (n>1) impedes it. Furthermore, this effect is much more pronounced in shear-thinning fluids than that in shear-thickening fluids. © 2010 Elsevier Ltd.
Citation: International Journal of Heat and Mass Transfer (2010), 53(19-20): 4152-4167
URI: https://doi.org/10.1016/j.ijheatmasstransfer.2010.05.038
http://repository.iitr.ac.in/handle/123456789/2430
Issue Date: 2010
Keywords: Circular cylinder
Nusselt number
Power-law fluids
Prandtl number
Reynolds number
Unsteady forced convection heat transfer
ISSN: 179310
Author Scopus IDs: 34870272400
14521775900
56657757000
Author Affiliations: Patnana, V.K., Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, UP, India
Bharti, R.P., Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, UP, India
Chhabra, R.P., Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, UP, India
Corresponding Author: Chhabra, R.P.; Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, UP, India; email: chhabra@iitk.ac.in
Appears in Collections:Journal Publications [CH]

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