An investigation on thermo-hydraulic performance of a flat-plate channel with pyramidal protrusions

Abstract

h i g h l i g h t sPyramidal protrusions are proposed for heat transfer enhancement applications. CFD is used to study the hydrothermal performance of the proposed surface pattern. The overall performance of a flat-plate channel is enhanced. The obtained results are investigated using entropy generation analysis. a b s t r a c tIn this study, a flat-plate channel configured with pyramidal protrusions are numerically analysed for the first time. Simulations of laminar single-phase fluid flow and heat transfer characteristics are developed using a finite-volume approach under steady-state condition. Pure water is selected as the coolant and its thermo-physical properties are modelled using a set of temperature-dependent functions. Different configurations of the channel, including a plain channel and a channel with nature-inspired protruded surfaces, are studied here for Reynolds numbers ranging from 135 to 1430. The effects of the protrusion shape, size and arrangement on the hydrothermal performance of a flat-plate channel are studied in details. The temperature of the upper and lower surfaces of the channel is kept constant during the simulations. It is observed that utilizing these configurations can boost the heat transfer up to 277.9% and amplify the pressure loss up to 179.4% with a respect to the plain channel. It is found that the overall efficiency of the channels with pyramidal protrusions is improved by 12.0-169.4% compared to the plain channel for the conditions studied here. Furthermore, the thermodynamic performance of the channel is investigated in terms of entropy generation and it is found that equipping the channels with pyramidal protrusions leads to lower irreversibility in the system.

Laminar convective heat transfer of shear-thinning liquids in rectangular channels with longitudinal vortex generators

“…The ability of the solver to reliably predict Newtonian fluid flow and heat transfer in rectangular channels with VGs was assessed in previous studies conducted by the authors [14,16,21]. The solver has been extended to model non-Newtonian fluid flow and heat transfer.…”

“…Equipping rectangular channels with vortex generators (VGs) has been demonstrated to be a promising method to passively augment the heat transfer performance [10][11][12][13][14]. Vortex generators with various shapes such as wing [15], winglet [16], rib [17,18], pin fin [19] and surface protrusions [20][21][22][23] have been utilised for heat transfer enhancement applications. The pressure difference between two sides of VGs leads to flow separation from the side edges, which generates longitudinal, transverse and horseshoe vortices [24].…”

“…The total pressure drop (Δp) [Pa] was evaluated using out p and in p , which are areaweighted static pressures at the exit and the entrance of the main zone, respectively.The overall performance of the channels should be evaluated considering both the heat transfer and the friction loss. Therefore, the overall performance of the channels (η) is measured using a well-accepted performance evaluation parameter[14,21, 32, 33,[42][43][44]. In Eq.15, Num is the mean Nusselt number and the subscript "s" stands for the plain channel.Cases with η>1.0 show better overall performances compared with the equivalent plain channel.…”

Inlet tube spacing and protrusion inlet effects on multiple circular tubes in the laminar, transitional and turbulent flow regimes

“…Only 42 of these papers are related to thermal and/or fluid sciences. In most of these papers protrusions were investigated as a heat transfer enhancement mechanism, such as in references [1][2][3][4][5][6][7], however, it was not investigated as part of inlet effects.…”

“…References [1][2][3][4][5][6][7][8][9][10][11][12][13][14] had in common that studies were done on inlet effects on an application level with multiple channels through which flow occurred. This is an important difference to more fundamental studies where only one channel at a time were considered, investigating the effect of the inlet geometry and/or inlet velocity distribution.…”