Topic
Lubrication theory
About: Lubrication theory is a research topic. Over the lifetime, 1713 publications have been published within this topic receiving 50261 citations. The topic is also known as: Fluid bearing.
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TL;DR: Results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices.
13 citations
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TL;DR: A gas can lubricate bearing surfaces just as a liquid can, but the unit loads that a gas film can support are much lower because the viscosity of the gas is several orders of magnitude lower than that of a liquid lubricant as mentioned in this paper.
13 citations
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TL;DR: In this article, a heat transfer correlation for the steady-state natural convection in a meniscus-shaped cavity was established and a closed-form exact conduction solution was also presented for the cylindrical case.
13 citations
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01 Jul 2020
TL;DR: In this article, the authors examined the flow distribution and pressure drop characteristics of interdigitated flow fields with constant and tapered cross-sections and found that the most influential parameter is the ratio between the pressure drop along the channel due to viscous stresses and the pressure dropping across the electrode due to Darcy's viscous resistance.
Abstract: Optimization of flow fields in redox flow batteries can increase performance and efficiency, while reducing cost. Therefore, there is a need to establish a fundamental understanding on the connection between flow fields, electrolyte flow management and electrode properties. In this work, the flow distribution and pressure drop characteristics of interdigitated flow fields with constant and tapered cross-sections are examined numerically and experimentally. Two simplified 2D along-the-channel models are used: (1) a CFD model, which includes the channels and the porous electrode, with Darcy’s viscous resistance as a momentum sink term in the latter; and (2) a semi-analytical model, which uses Darcy’s law to describe the 2D flow in the electrode and lubrication theory to describe the 1D Poiseuille flow in the channels, with the 2D and 1D sub-models coupled at the channel/electrode interfaces. The predictions of the models are compared between them and with experimental data. The results show that the most influential parameter is γ , defined as the ratio between the pressure drop along the channel due to viscous stresses and the pressure drop across the electrode due to Darcy’s viscous resistance. The effect of R e in the channel depends on the order of magnitude of γ , being negligible in conventional cells with slender channels that use electrodes with permeabilities in the order of 10 − 12 m 2 and that are operated with moderate flow rates. Under these conditions, tapered channels can enhance mass transport and facilitate the removal of bubbles (from secondary reactions) because of the higher velocities achieved in the channel, while being pumping losses similar to those of constant cross-section flow fields. This agrees with experimental data measured in a single cell operated with aqueous vanadium-based electrolytes.
13 citations
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TL;DR: In this paper, a scheme for the promotion of viscous lubrication in wire drawing is analyzed, which is built up by means of close tolerance tube installed in front of the die.
Abstract: A scheme for the promotion of viscous lubrication in wire drawing is analyzed. Lubricant pressure is built up by means of close tolerance tube installed in front of the die. In the die, plasticity is maintained by the combination of fluid pressure and wire tension. In the analysis presented here the lubricant flow rate and film thickness variation in the die are solved for as well as the necessary length of pressure tube. Pressure and temperature effects on the lubricant viscosity and strain hardening effects on the wire metal are included in the analysis. Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Chicago, Illinois, October 1961.
12 citations