Effect of Net Geometry on the Nusselt Number Distribution for Channel Flow

Abstract

For channel flow between two parallel plates, obstacles may take the form of ordered asymmetrical porous nets. The dimensions of this net will affect the resulting variations in the laminar velocities and the local heat and mass transfer coefficients. This article presents a numerical study of the effect of an inert insulating net and its geometry on the heat transfer characteristics in such a system. The governing equations for momentum, continuity, and energy equation were solved in a three-dimensional domain using a commercial CFD software for fully developed flow with constant temperature boundary conditions. The local Nusselt number was calculated from the resulting temperature distribution. The effects of location, spacing, and number of the longitudinal and transverse ribs of the net on the distributions and on the mean Nusselt number of the two plates are analyzed. Enhancement factors of the mean Nusselt number were found to increase between 13 and 330% as the number of transverse ribs increased from four to 29 for typical nets with a 0.27 mm thickness. However, for the same nets, the enhancement factors of the mean Nusselt number were found to decrease between 16 and 50% as the number of longitudinal ribs increased from four to 14.

Synchronizing time-varying discrete heating elements in forced convection for minimal thermal resistance

“…Once b T SS ; b T cos and b T sin are determined, they can be combined in order to calculate either the hot spot temperature directly with Eq. (9) or, if required, calculate explicitly the temperature field at every time in the domain with Eq. (3).…”

“…Because of that, the search for better, cheaper and more reliable cooling methods has consistently received much attention from the technical community for the last twenty years [1][2][3][4][5][6][7][8][9].…”

Effect of a net on the limiting current distribution in a parallel plate electrochemical reactor: part I. Individual effects

“…The correlation and discussion for this can be obtained from our previous work [23]. We use the afore-mentioned correlation along with Eq.…”

“…We use the previously computed distribution of the Nusselt number [23] and the analogy between heat and mass transfer [26]. In an aluminum anode the surface reaction results in a layer of alumina [10,25], which drives the anode to be mass-transfer controlled by the transport of OH -ions.…”

“…The net is inert and limiting current analyses based on existing models for obstacles in the flow field for both laminar and turbulent flow, reported in the literature [15][16][17][18][19][20][21], provide some perspective albeit not one that is readily applicable to our case. As a first step toward understanding of these net-based PPERs, we consider the limiting current density analysis based on the solution to the closely associated heat-transfer problem [22,23].…”