Slip flow in converging and diverging channels

The growing development in the thermal engineering and nano-technology, much attention has been paid on the thermal properties of nanoparticles which convey many applications in industrial, technological and medical era of sciences. The noteworthy applications of nano-materials included heat transfer enhancement, thermal energy, solar systems, cooling of electronics, controlling the heat mechanisms etc. Beside this, entropy generation is an optimized scheme which reflects significances in thermodynamics systems to control the higher energy efficiency. On this end, present work presents the slip flow of Jeffrey nanofluid over a stretching sheet with applications of activation energy and viscous dissipation. The entropy generation features along with Bejan number significance is also addressed in present analysis. Buongiorno model of nanofluid is used to discuss the heat and mass transfer. The formulated flow equations are attained into non-dimensional form. An appropriate ND MATHEMATICA built-in scheme is used to find the solution. The solution confirmation is verified by performing the error analysis. For developed flow model and impacted parameters, a comprehensive graphical analysis is performed. It is observed that slip phenomenon is used to decays the velocity profile. Temperature and concentration are in direct relation with Brownian motion parameter and activation energy respectively. Entropy and Bejan number have same results for greater diffusion parameter.

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Rheological Basics for Modeling of Extrusion Process of Wood Polymer Composites

Polymers ◽

10.3390/polym13040622 ◽

2021 ◽

Vol 13 (4) ◽

pp. 622

Author(s):

Krzysztof Wilczyński ◽

Kamila Buziak ◽

Adrian Lewandowski ◽

Andrzej Nastaj ◽

Krzysztof J. Wilczyński

Keyword(s):

Polymer Composites ◽

Process Modeling ◽

Slip Flow ◽

Extrusion Process ◽

Process Conditions ◽

Rheological Models ◽

Wood Polymer ◽

Slip Effects ◽

Process Simulations ◽

Wood Polymer Composites

Wood polymer composites are materials with pseudoplastic and viscoelastic properties. They have yield stress and exhibit slip during flow. Studies on extrusion and rheology, as well as on process modeling of these highly filled materials are limited. Extensive rheological and extrusion modeling studies on the wood polymer composite based on the polypropylene matrix were performed. Viscous and slip flow properties were determined (with Rabinowitsch, Bagley, and Mooney corrections) at broad (extrusion) range of shear rate and temperature, using a high-pressure capillary rheometer. Rheological models of Klein and power-law were used for flow modeling, and Navier model was applied for slip modeling. A novel global computer model of WPC extrusion with slip effects has been developed, and process simulations were performed to compute the extrusion parameters (throughput, power consumption, pressure, temperature, etc.), and to study the effect of the material rheological characteristics on the process flow. Simulations were validated experimentally, and were discussed with respect to both rheological and process modeling aspects. It was concluded that the location of the operating point of extrusion process, which defines the thermo-mechanical process conditions, is fundamentally dependent on the rheological materials characteristics, including slip effects.

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Why bumpy is better: The role of the dissipation distribution in slip flow over a bubble mattress

Physical Review Fluids ◽

10.1103/physrevfluids.1.054101 ◽

2016 ◽

Vol 1 (5) ◽

Cited By ~ 8

Author(s):

A. Sander Haase ◽

Jeffery A. Wood ◽

Rob G. H. Lammertink ◽

Jacco H. Snoeijer

Keyword(s):

Slip Flow

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