Wall effect for a sphere falling through a non-Newtonian fluid in a rectangular duct

Machač, Ivan; Lecjaks, Z.

doi:10.1016/0009-2509(94)00211-9

Cited by 30 publications

(14 citation statements)

References 6 publications

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“…However, for the sphere with a diameter of 3 cm, there was a fairly large decrease the wall factor as the column width was reduced from 16 to 9 cm, respectively as geometric factor was increased. This is expected (Machac and Lecjaks, 1995,) considering the ratio between the column width and sphere diameter is relatively high at a value of 0.3. …”

Section: Effect Of Column Width On Terminal Velocitymentioning

confidence: 91%

Wall Effects for the Free Rise of Solid Spheres in Moderately Viscous Liquids

et al. 2002

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For the first time ever, the influence of wall effects on the free rise of a buoyant solid sphere in a square column in a non‐Newtonian (pseudoplastic) fluid was determined. It was found that in most cases, as the column width decreased, the terminal rise velocity of the sphere would decrease as well. It was also discovered that wall effects could change the rising sphere trajectory. Spheres that displayed a spiraling trajectory in larger columns would display a more linear trajectory in smaller columns. Occasionally, due to this change in trajectory, the solid sphere terminal velocity would increase as the column width decreased. This phenomenon (the positive wall effect) has not been reported for falling spheres in Newtonian or non‐Newtonian fluids.

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Section: Effect Of Column Width On Terminal Velocitymentioning

confidence: 91%

Wall Effects for the Free Rise of Solid Spheres in Moderately Viscous Liquids

et al. 2002

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“…Most theoretical and experimental work has been carried out with cylindrical boundaries; however, some results are also available for boundaries of triangular and square cross-sections (Happel and Bart, 1974; Miyamura et al, 1981; Chow et al, 1989; Ilic et al, 1992;Balaramakrishna and Chhabra, 1992;Machac and Lecjaks, 1995). Most theoretical and experimental work has been carried out with cylindrical boundaries; however, some results are also available for boundaries of triangular and square cross-sections (Happel and Bart, 1974; Miyamura et al, 1981; Chow et al, 1989; Ilic et al, 1992;Balaramakrishna and Chhabra, 1992;Machac and Lecjaks, 1995).…”

mentioning

confidence: 99%

Wall effect for the fall of spheres in cylindrical tubes at high reynolds number

Uhlherr

Chhabra

1995

Can J Chem Eng

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New experimental results on the wall effect for sphere motion in cylindrical tubes are presented and discussed for the conditions dlD 5 0.9 and Re,,, I 2oooO. Extensive comparisons with previous studies have been carried out to evaluate their predictability and to demonstrate the utility of the present results.The wall factor, defined as the ratio of settling velocity in an unbounded medium to that measured in a cylindrical tube, is found to depend on sphere-to-tube diameter ratio and on sphere Reynolds number. However, for small values of the Reynolds number (Re 0.5), as well for large values (Re 2 loOO), the Reynolds number dependence of the wall factor disappears; in these regions, only the dependence on diameter ratio remains. De nouveaux rksultats exHrimentaux sur l'effet de paroi pour le dtplacement des sphbres dans des tubes cyclindriques sont prtsentks et analyds pour les conditions dlD s 0,9 Re,,, S 2000. On a effectue des c o m p s o n s ~OUS&S avec les ktudes antkrieures afin d'tvaluer la caractbre praictif du modble et de dtmontrer I'utilitk des prtsents r6sultats.On a trouvt que le facteur de paroi, dtfini c o m e le rapport entre la vitesse de dkantation dans un milieu infini et la vitesse dans un tube cylindrique, dtpendait du rapport de diamktre sphkres-tube et du nombre de Reynolds des sphtres. Cependant, pour le petites valeurs du nombre de Reynolds (Re s 0.5) c o m e pour les grands (Re I IOOO), la dtpendance du facteur de paroi par rapport au nombre: de Reynolds disparait; dans ces rkgions, seule subsiste la dkpendance par rapport au rapport des diambtres.Keywords: sphere drag, wall effect, terminal velocity. onfining walls are well known to exert a retarding C effect on a sphere in free fall. A knowledge of the wall

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“…of particle diameter to effective container diameter [14] should be taking into consideration before building flow tank and selecting particle size.…”

Section: Discussionmentioning

confidence: 99%

Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

Motanated¹

2017

GEP

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Sedimentary processes have direct effects on the geometry, distribution, and geophysical and geochemical properties of sedimentary rocks. Being able to qualitatively and quantitatively visualize the movement vector of sediments in fluid media is essential for understanding the complicated earth surface processes. Nonintrusive measuring and observing the interaction between the movement of fluid media and particles by a laser sheet flow visualization technique requires a light source that is thin and monochromatic. Yet, an ideal laser sheet generator is rather expensive and inaccessible, especially for schools and universities residing in low-income countries. This project is proposing a less-expensive option for a laser sheet source for nonintrusive flow visualization and modeling. Here, cylindrical lens is used to convert from point laser into sheet laser. Multiple combinations of laser diodes of various wavelength (nanometer) and power (milliwatt) and cylindrical lenses of various dimensions are analyzed. The pair that is able to produce the thinnest and brightest light sheet is not only effective but also affordable. The combination of manufactured laser module of 532 nm 50 mW and a single rod lens is able to generate a light sheet that is less than 4 mm thick. When choosing a laser module, this research recommends one at a wavelength of 532 nm with any electric power (high wattage results in high lumens).

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Wall effect for a sphere falling through a non-Newtonian fluid in a rectangular duct

Cited by 30 publications

References 6 publications

Wall Effects for the Free Rise of Solid Spheres in Moderately Viscous Liquids

Wall Effects for the Free Rise of Solid Spheres in Moderately Viscous Liquids

Wall effect for the fall of spheres in cylindrical tubes at high reynolds number

Flow Visualization and Modeling for Education and Research in Sedimentary Processes: An Accessible and Inexpensive Alternative

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