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Steady-state heat transfer and pressure drop data for single-phase viscous fluid flows (2 ≤ Re ≤ 400) in a single-pass U-type counterflow plate heat exchanger (PHE) with chevron plates are presented. With vegetable oil as test fluid (130 < Pr < 290), three different plate arrangements are employed: two symmetric (β = 30 deg/30 deg and 60 deg/60 deg) and one mixed (β = 30 deg/60 deg). The effects of chevron angle β, corrugation aspect ratio γ, and flow conditions (Re, Pr, μ/μw on Nu and f characteristics of the PHE are delineated. The results show a rather complex influence of plate surface corrugations on the enhanced thermal-hydraulic behavior. Relative to the performance of equivalent flat-plate packs, chevron plates sustain up to 2.9 times higher heat transfer rates on a fixed geometry and constant pumping power basis, and require up to 48 percent less surface area for the fixed heat load and pressure drop constraint.

The use of CFD (Computational Fluid Dynamics) is a powerful engineering analysis tool to reduce distortion, improve yield and to improve “first-time” quality. In this paper, CFD was used to understand quenchant flow in a quench tank, and to understand the effect of quenchant flow on part distortion. FLUENT was used to simulate the quenchant flow through a quench rack of automotive pinions. The analysis showed several locations where the flow could be improved in the quench tank, and identified regions of quenching non-uniformity on the parts. The flow on the parts was examined on the stem, the head and the overall pinion, to identify locations of suspected high distortion.

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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.