Computational Modeling of Enhanced Laminar Flow Heat Transfer in Viscoplastic Fluids in Corrugated-Plate Channels

Abstract

The enhanced heat transfer in laminar viscoplastic, shear thinning, Herschel-Bulkley fluid flows in sinusoidal corrugated-plate channels is investigated. With uniform-temperature plate walls, periodically developed flows are considered for a wide range of flow rates (10 ≤ Reg ≤ 700) and pseudoplastic flow behavior indices (n = 0.54, 0.8, and 1.0; the latter representing a Bingham plastic). The effects of fluid yield stress are simulated for the case where τy = 1.59 N/m2, representing a 0.5% xantham gum aqueous solution. Typical velocity and temperature distributions, along with extended results for isothermal friction factor ƒ and Colburn factor j are presented. The effect of the yield stress is found to be most dominant at low Reg regardless of the power law index n, and the recirculation or swirl in the wall trough regions is weaker than in the cases of Newtonian and power-law liquids. At higher Reg, the performance of the Herschel-Bulkley fluid asymptotically approaches that of the non-yield-stress power-law fluid. At low Reg, the yield stress increases ƒ by an order of magnitude and j is enhanced because of the higher wall gradients imposed by the plug-like flow field. The relative heat transfer enhancement, represented by the ratio (j/ƒ), and the role of the fluid yield stress and shear-thinning (or pseudoplastic) behaviors are also discussed.

Laminar flow in chevron-type plate heat exchangers: CFD analysis of tortuosity, shape factor and friction factor

“…Of particular interest is the PHE which is extensively used in the chemical, pharmaceutical and food industries, among others [1,7,8]. Laminar or low Reynolds number flows are usually obtained when liquid foods are processed in PHEs, this low Reynolds number range being also observed in micro PHEs [7,[9][10][11][12]. Besides the importance in pressure drops estimations, the development of Fanning fric-tion factor correlations, determined for the isothermal laminar flow of Newtonian fluids in PHEs, can be useful in other areas.…”

Models for Pressure Drop and Heat Transfer in Air Cooled Compact Wavy Fin Heat Exchangers

“…The onset of macroscopic mixing was directly linked to significant increases in local heat transfer. Metwally and Manglik (2000) investigated the enhanced heat transfer behavior of laminar shear-thinning, power-law fluid flows in sinusoidal corrugated-plate channels. With duct plates at uniform wall temperature, they considered periodically developed flows for a wide range of channel corrugation aspect ratio (0 ≤ γ ≤ 1), flow rates (10 ≤ Re g ≤ 1500), and pseudoplastic flow behavior indices (n = 0.5, 0.8, and 1.0).…”