Natural convective heat transfer influence between two spheres in a packed bed

Baek, Seong-Il; Moon, Je-Young; Chung, Bum-Jin

doi:10.1016/j.icheatmasstransfer.2022.106430

Cited by 5 publications

(1 citation statement)

References 34 publications

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“…Natural convection is propelled by the density differential induced by the temperature gradient within a fluid. This mechanism offers an economical, low-noise and convenient way to cool a heated wall of an adjoining fluid, and has thus been frequently employed in thermal energy storage systems and pebble bed reactors in recent years 1 . The phenomenon of heat transfer via external natural convection over a single sphere submerged in a quiescent fluid is a classical issue in this field, and it is frequently utilized in nuclear power engineering 2 .…”

Section: Introductionmentioning

confidence: 99%

Nu–Gr correlation for laminar natural convection heat transfer from a sphere submitted to a constant heat flux surface

Zhen,

Tana,

Sun

et al. 2024

Sci Rep

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The work numerically investigated laminar natural convection heat transfer from the single sphere with a constant heat flux surface in air over the wide range of Grashof number ($$10 \le Gr \le 10^{7}$$ 10 ≤ G r ≤ 10 7 ). The more efficient and precise numerical method based on Bejan et al. was employed here, the accuracy of which has been confirmed through validation against a single sphere case. The heat transfer characteristics were systemically analyzed in terms of isothermal contours and streamlines around the sphere, dimensionless temperature and velocity profiles. Additionally, local Nusselt number as well as local pressure and friction drag coefficients were studied with different Grashof number. In comparison to the sphere with uniform heat flux surface, the heat transfer from the isothermal sphere was found to be enhanced attributable to a more robust buoyancy force and a steeper temperature gradient. Moreover, the average Nusselt number for the sphere with a constant heat flux between 60.4 and 98.6% of the isothermal sphere’s value, this range being contingent upon the specific Grashof number. What’s more, the proposed correlation addresses a notable void in the predictive understanding of heat transfer from the sphere with uniform heat flux, which is scenario prevalent in various engineering applications, particularly for the cooling of electrical and nuclear systems, and offer values for academic research.

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Section: Introductionmentioning

confidence: 99%