An experimental investigation of the cross‐flow of power law liquids past a bundle of cylinders and in a bed of stacked screens

Abstract

The steady flow of power‐law polymer solutions normal to arrays of cylinders and in a bed of screens has been investigated experimentally. Extensive pressure drop measurements have been made for three different test cells (two tube bundles and one bed made of screens) of different voidages for a series of inelastic carboxymethyl cellulose and sodium alginate aqueous solutions. The resulting values of friction factor correlate well with a modified definition of the Reynolds number based on the capillary bundle representation of the bed. The new data extend considerably the range of voidage values from ∼0.6 to ∼0.87. Extensive comparisons have also been made between the present experimental data and our previous calculations based on the use of simple cell models. The close correspondence between the two demonstrates the utility of such idealized analyses. All in all, the present results embrace the following ranges of physical and kinematic conditions: Reynolds number: 0.01 to ∼1200; power‐law flow behaviour index: 0.38 to 1; and three values of voidage, namely, 0.74, 0.78 and 0.87.

Flow of Newtonian and power law liquids in tube bundles

“…Undoubtedly, the actual flow field in a tube bundle is quite complex and is strongly influenced by the detailed geometrical configuration, and it is customary to approximate the frictional pressure drop as a weighted average of the corresponding values for the tangential (or parallel) and the normal (or cross) flow otherwise under identical conditions. While our previous work (Prasad and Chhabra, 2001) reported the results of an extensive experimental study for the cross-flow of scores of Newtonian and power law liquids in tube bundles, the analogous results for the parallel flow are reported herein.…”

“…Further statistical analysis revealed no discernable trends. At this juncture, it is useful to recall the analogous expression for the cross-flow configuration reported elsewhere (Prasad and Chhabra, 2001) is given by:…”

“…In addition to the aforementioned specific examples, it is frequently required to estimate miscellaneous frictional losses across various equipments and fittings in a plant (Bandyopadhyay and Das, 2007;Fester et al, 2007Fester et al, , 2008Chhabra and Richardson, 2008). These as well as many other potential applications have been described and reviewed in detail in our previous study (Prasad and Chhabra, 2001). It is readily acknowledged that the parameter of central interest in all such applications is the estimation of the frictional pressure drop in a tube bundle of known geometry and kinematic flow conditions.…”

Convective heat transfer for power law fluids in packed and fluidised beds of spheres

“…) and for the free rise/fall of uid particles (Gummalam and Chhabra, 1987;Gummalam et al, 1988;Jarzebski and Malinowski, 1986;Chhabra, 1998;Zhu, 2001, etc.). Indeed, fair to good degree of correspondence between the theoretical predictions and experimental results have been reported for Newtonian and inelastic power law type liquids Shibu et al, 2001;Prasad and Chhabra, 2002;Mandhani et al, 2002;Malleswara Rao and Chhabra, 2003) up to moderate values of the Reynolds number. The range of applications shows the versatility of this approach in general and of the free surface cell model in particular.…”

Flows of inelastic non-Newtonian fluids through arrays of aligned cylinders. Part 2. Inertial effects for square arrays

“…Prakash, Gupta and Mishra [9] collected experimental data from various sources and developed a model, based on the flow through a channel of varying cross-section, in an attempt to collapse the data. More recently, Prasad and Chhabra [10] presented experimental data for flows of CMC solutions through triangular and staggered square arrays of cylinders for solid area fractions lower than those considered in [8].…”