Forced convection heat transfer from a spheroid to a power law fluid

Sreenivasulu, B.; Srinivas, B.; Ramesh, K.

doi:10.1016/j.ijheatmasstransfer.2013.10.065

Cited by 23 publications

(10 citation statements)

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“…The bulk of these studies have been reviewed, among others, by Clift et al in their classic treatise, and more recently by Michaelides and Kishore and co-workers. − All in all, the currently available numerical simulations in this field are generally limited to the axisymmetric flow regime, and scant experimental results are consistent with these predictions . The next generation of developments in this field have dealt with the prediction of the drag and Nusselt number for oblates and prolates in power-law fluids. − Not only are these numerical results restricted to the axisymmetric flow regime, but there are no experimental results available to substantiate or refute the numerical predictions of drag on prolates and oblates in power-law fluids. In a nutshell, at low Reynolds numbers, shear-thinning power-law viscosity tends to augment the drag over and above that in Newtonian fluids whereas the effect of power-law index progressively diminishes with increasing Reynolds number due to the increasing dominance of inertial effects over viscous effects.…”

Section: Introductionmentioning

confidence: 99%

Spheroids in Viscoplastic Fluids: Drag and Heat Transfer

Gupta

Chhabra

2014

Ind. Eng. Chem. Res.

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In the present work, the forced convection momentum and heat transfer aspects of isothermal spheroidal particles (both prolates and oblates) in Bingham plastic fluids have been numerically investigated in the steady axisymmetric flow regime. Extensive results on the detailed structures of the flow and temperature fields are presented and analyzed in terms of the streamline and isotherm contours, and the yield surfaces as well as their dependence on the pertinent influencing parameters, namely, Reynolds number (1 ≤ Re ≤ 100), Prandtl number (1 ≤ Pr ≤ 100), and Bingham number (0 ≤ Bn ≤ 100) are delineated. Five values of aspect ratio, e = 0.2 and 0.5 (oblates) and e = 2 and 5 (prolates), and the limiting case of a sphere, i.e., e = 1, are considered here to elucidate the effect of shape on both drag and Nusselt number values. Broadly, for a given shape (value of e), drag shows the classic inverse dependence on the Reynolds number and a positive correlation with the Bingham number. Similarly, the mean Nusselt number bears a positive dependence on each of these parameters, Re, Pr, and Bn, due to the sharpening of the temperature gradient in the thin thermal boundary layer. The present drag results have been correlated via the use of a modified Reynolds number whereas the heat transfer results have been consolidated in terms of the Colburn j H factor, thereby enabling their prediction in a new application.

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Section: Introductionmentioning

confidence: 99%

Spheroids in Viscoplastic Fluids: Drag and Heat Transfer

Gupta

Chhabra

2014

Ind. Eng. Chem. Res.

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“…The domain sizes corresponding to the selected case have been used in generating the simulation results in the paper. [2] two tandem circular cylinders Newtonian forced convection <2% Bhattacharya and Singh [4] sphere Newtonian mixed convection <2% Dhole et al [7] sphere power law steady 2D axi-symmetric <1% Kotouc et al [9] sphere Newtonian mixed convection <2% Alassar [11] oblate spheroid incompressible fluid forced convection <1% Kishore and Gu [12] spheroid Newtonian momentum and heat transfer <2% Sreenivasulu et al [16] unconfined spheroid power law forced convection <1% Sreenivasulu and Srinivas [17] unconfined spheroid Newtonian mixed convection <1%…”

Section: Domain and Grid Independencementioning

confidence: 99%

“…A good number of works have been reported earlier with cylinders [2,3] and spheres [4][5][6][7][8][9] as immersed objects. An examination of literature revealed that previous works pertaining to spheroids are focused on transport properties in case of Newtonian fluids [10][11][12][13], power law fluids [14][15][16] and tandem spheroids in Newtonian fluids [17][18][19] whereas studies on tandem spheroids in power law fluids is scarce [20].…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer from Two Spheroids in Tandem to a Power Law Fluid by Forced and Mixed Convection Modes

Sreenivasulu¹,

Sree²,

Srinivas³

et al. 2020

TI-IJES

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A numerical study is carried out on convective heat transfer from an unconfined and stationary tandem of two spheroids to the surrounding flowing power law fluid of constant physical properties. Two modes of convection viz., forced convection and mixed convection are considered for the present study. The surface of both the spheroids is maintained at constant temperature. The focus of the investigation is to obtain the effect of pertinent variables (Reynolds number, Prandtl number, Richardson number, aspect ratio, power law index and space between two spheroids) on the average Nusselt number. Reynolds number is taken as 1, 25, 50 and 100. Prandtl number considered is 1 and 100. Chosen range is 0.5 to 2.0 for power law index. Spacings taken are 4a and 8a (here 2a is the length of spheroid in direction parallel to flow). The study is also repeated for the case of mixed convection where in Richardson number is taken as 0.5, 12, 1.5 and 2.0.

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“…The latter problem has been considered in numerous papers based on the numerical solutions to momentum and heat transfer equations in the ambient fluid (gas) in the ellipsoidal coordinate system. The analysis of [52,53,54,55,56] was based on the assumption that the body surface was fixed. Juncu [57] took into account changes in body temperature with time, while assuming that there is no temperature gradient inside the body (the thermal conductivity of the body was assumed infinitely high).…”

Section: Hydrodynamic Models (Mono-component Droplet Heating and Evapmentioning

confidence: 99%