Deposition of a viscous fluid on the wall of a tube

Abstract

Measurements of the amount of fluid left behind when a viscous liquid is blown from an open-ended tube are described.

Film thickness measurements in liquid–liquid slug flow regimes

“…However, this is only possible when slug lengths are greater than the previously defined threshold of L Ã D P 1:86. Other authors have overcome this variation in film thickness with slug length by using indirect measurement techniques (Grimes et al, 2007;Irandoust and Andersson, 1989;Kashid et al, 2005;Taylor, 1960), that give an average of the film thickness along the length of the slug. Where possible, the experimental data presented in this sub-section was measured at the flat film region.…”

“…8 the AR20/water measurements follow a similar trend to the model of Aussillous and Quere (2000), however, this model under predicts the magnitude of the film, particularly as the Capillary number increases, Ca > 0.03. Aussillous and Quere (2000) developed an empirical correlation based on the data of Taylor (1960) in which they modified Bretherton's lubrication theory to account for flows where the film occupies a significant portion of the channel. In the present study, the film present in the AR20/water flows occupies between 10% and 22% of the channel.…”

“…In their pioneering work (Fairbrother and Stubbs, 1935), while examining liquid flow rates in capillaries using an indicator bubble, noted that the bubble moved faster than the liquid and concluded that this was due to the presence of a liquid film surrounding the bubble. Taylor (1960) using a similar methodology measured the magnitude of this film by comparing the difference between the bubble and mean flow velocity. Aussillous and Quere (2000) developed an empirical correlation based on the data of Taylor and found a dependence of the normalised film thickness on a single parameter, namely the Capillary number.…”

Novel synthesis of thick wall coatings of titania supported Bi poisoned Pd catalysts and application in selective hydrogenation of acetylene alcohols in capillary microreactors

“…A horizontal tube to be coated is first filled with the precursor solution, then gas displaces the liquid leaving some liquid along the walls. 27 This method was applied to obtain a 5-20 μm thick coating inside shorter (0.3 m) reactors 28 or a thin coating (90 nm) inside 10-m long reactors. 23,29 Another derivative of the dip-coating method, the fill-and-dry method, can be used to obtain [10][11][12][13][14][15][16][17][18][19][20] μm thick catalytic coatings inside short reactors.…”

Profile of the liquid film wetting a channel

“…The dimensionless parameter Ca ¼ gV=c (V is the velocity of the solid, g the liquid viscosity, and c the surface tension) links viscous and surface tension forces. Taylor 5 found that a Ca 1=2 behavior describes the deposition of a liquid film formed in slug flow in a capillary tube. At the same time, Bretherton 6 performed a theoretical analysis, giving a Ca 2=3 law for long bubbles.…”