Numerical simulation by the FVM of coupled heat transfers by conduction, natural convection and radiation in honeycomb’s hollow bricks

Abstract

This paper presents a detailed numerical study, in steady state regime, of the interaction between two dimensional heat transfers by conduction, natural convection and radiation in double hollow bricks formed by two honeycomb walls separated by an air layer. The air motion in all cavities of the system is laminar. The left and right vertical sides of the hollow bricks are considered isothermal and maintained at different constant temperatures. The top and bottom horizontal sides are assumed to be adiabatic. The governing equations are solved using the finite volume method (FVM) and the SIMPLE algorithm. The impact of the thickness of the air layer on the global heat flux through the structure is discussed. The simulation results show that the variation of the overall heat flux through each hollow brick as a function of the temperature difference ΔT between the vertical sides of the system is almost linear for the different types of double hollow bricks considered.This linear thermal behaviour allowed the generation of appropriate overall heat exchange coefficients that permit fast and accurate prediction of heat transfers through the hollow bricks without solving the complex system of equations governing the coupled heat transfers. Comparison of the performance of different types of double hollow bricks is made.

Interaction of Surface Radiation With Laminar and Turbulent Natural Convection in Tall Vertical Cavities: Analysis and Heat Transfer Correlations

“…The overall heat transfer through the cavity can be easily calculated from N u t , which is the sum of the Nusselt numbers given by the empirical relationships (22) and (25).…”

“…For cavities of low aspect ratios, the coupling of laminar natural convection and surface radiation has been widely studied [17][18][19][20][21][22][23][24][25]. In general, these studies have shown that surface radiation considerably modifies the dynamic and thermal fields with a reduction in the convective heat transfer but a significant increase of the overall heat transfer between the active walls.…”

“…In a laminar regime, the coupled heat transfer through alveolar walls, which are constructed with bricks having honeycombs of weak A, was analyzed by Abdelbaki and Zrikem [23], Abdelbaki et al [34], and Boukendil et al [35]. These studies were extended subsequently to double alveolar walls containing an air layer of high aspect ratio A (Boukendil et al [36]).…”

Numerical investigation of conjugate heat transfer in the presence of two fluid separated by a rigid wall

“…The thermal phenomenon induced by this type of heat transfer is an interesting question for many studies focusing on building thermal area. [1][2][3][4][5][6][7] Further studies have been conducted investigating combined convection/conduction in other engineering fields such as heat exchangers. [8][9][10] Also, gas turbine design and their operation mode involves a very precise analysis of conjugate heat transfer for temperature field prediction and better cooling of turbine components.…”

“…This phenomenon is implicated in several industrial applications and has a very wide research interest. The thermal phenomenon induced by this type of heat transfer is an interesting question for many studies focusing on building thermal area 1‐7 . Further studies have been conducted investigating combined convection/conduction in other engineering fields such as heat exchangers 8‐10 .…”