On the discontinuity of the dissipation rate associated with the temperature variance at the fluid-solid interface for cases with conjugate heat transfer

In the present study, the immersed boundary (IB) method is applied as a tool to solve a conjugate heat transfer problem in a turbulent flow around a circular cylinder. This problem involves complexities such as transition, turbulent natural convection, and interaction of fluid convection and solid conduction. In order to enforce the velocity boundary condition at the IB, a second-order reconstruction method is employed. In order to handle coupling of the temperature field between different materials, the fluid-solid interface is approximated as a group of adjoining Cartesian faces from heterogeneous material regions. A Hermite-type interpolation is applied to reconstruct the temperature field across the fluid-solid interface with a reduced error. This approach has been verified with a heat transfer problem with an analytic solution and shows an improved result compared to the previous method. For the turbulent conjugate heat transfer problem around a circular cylinder, the predicted local Nusselt number shows a good agreement with the previous experiment. The statistical data obtained from this simulation can be used for turbulence modeling of heat transfer problems around a bluff body.

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Rigorous Modelling of Two-Equation Heat-Transfer Model Using Direct Simulations. 1st Report. Assessment and Reconstruction of Dissipation-Rate Equations for Temperature Variance.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.61.1114 ◽

1995 ◽

Vol 61 (583) ◽

pp. 1114-1121 ◽

Cited By ~ 1

Author(s):

Hirofumi Hattori ◽

Yasutaka Nagano

Keyword(s):

Heat Transfer ◽

Dissipation Rate ◽

Heat Transfer Model ◽

Rate Equations ◽

Transfer Model ◽

Temperature Variance

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Comparative study of conjugate heat transfer in a single-phase flow in wavy and raccoon microchannels

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-05-2019-0439 ◽

2019 ◽

Vol 30 (7) ◽

pp. 3791-3825 ◽

Cited By ~ 2

Author(s):

Nishant Tiwari ◽

Manoj Kumar Moharana

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Nusselt Number ◽

Dissipation Rate ◽

Conjugate Heat Transfer ◽

Single Phase ◽

Heat Dissipation ◽

Fluid Temperature ◽

Bulk Fluid ◽

Content Type

Purpose This paper aims to emphasize on studying various geometrical modification performed in wavy and raccoon microchannel by manipulating parameters, i.e. waviness (γ), expansion factor (α), wall to fluid thermal conductivity ratio (ksf), substrate thickness to channel height ratio (dsf) and Reynolds number (Re) for obtaining optimum parameter(s) that leads to higher heat dissipation rate. Design/methodology/approach A three-dimensional solid-fluid conjugate heat transfer numerical model is designed to capture flow characteristics and heat transfer in single-phase laminar flow microchannels. The governing equations are solved using finite volume method. Findings The results are presented in terms of average base temperature, average Nusselt number, pressure drop, dimensionless local heat flux, dimensionless wall and bulk fluid temperature, local Nusselt number and performance factor including axial conduction number. Heat dissipation rate with raccoon microchannel configuration is found to be higher compared to straight and wavy microchannel. With waviness of γ = 0.167, and 0.267 in wavy and raccoon microchannel, respectively, performance factor attains maximum value compared to other waviness for all values of Reynolds number. It is also found that the effect of axial wall conduction in wavy and raccoon microchannel is negligible. Additionally, thermal performance of wavy and raccoon microchannel is compared with straight microchannel. Practical implications In recent past years, much complex design of microchannel has been proposed for heat transfer enhancement, but the feasibility of available manufacturing techniques to fabricate complex geometries is still questionable. However, fabrication of wavy and raccoon microchannel is easy, and their heat dissipation capability is higher. Originality/value This makes the difference in wall and bulk fluid temperature smaller. Thus, present work highlighted the dominance of axial wall conduction on thermal and hydrodynamic performance of wavy and raccoon microchannel under conjugate heat transfer situation.

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