Lattice Boltzmann modeling of the capillary rise of non‐Newtonian power‐law fluids

2021 ◽  
Author(s):  
Fang Shan ◽  
Hongyan Du ◽  
Zhenhua Chai ◽  
Baochang Shi
Keyword(s):  
Power Law ◽  
Lattice Boltzmann ◽  
Capillary Rise ◽  
Power Law Fluids ◽  
Lattice Boltzmann Modeling

A theoretical study on the capillary rise of non-Newtonian power-law fluids

2020 ◽  
Vol 81 ◽  
pp. 768-786
Author(s):  
Fang Shan ◽  
Zhenhua Chai ◽  
Baochang Shi
Keyword(s):  
Power Law ◽  
Theoretical Study ◽  
Capillary Rise ◽  
Power Law Fluids

Lattice Boltzmann Modelling for Natural Convection in Power-Law Fluids within a Partially Heated Square Enclosure

2020 ◽  
Author(s):  
Siva Subrahmanyam Mendu ◽  
P.K. Das
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Source ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Collision Term ◽  
Square Enclosure ◽  
Power Law Fluids ◽  
Power Law Index

Abstract The present paper reports the numerical investigations for steady-state natural convection in power-law fluids inside a square enclosure embedded with bottom discrete heaters. The Lattice Boltzmann Method (LBM) is employed to model the flow and heat transfer phenomenon at different combinations of power-law index, Rayleigh number, and heat source length for a constant Prandtl number. The buoyancy force is incorporated in the collision term of the LBM through Boussinesq approximation. Simulation outcomes are furnished using streamlines and, temperature contours, velocity profiles and variation of heat transfer on the non-adiabatic walls to probe natural convection phenomena. The results indicate that the temperature and the flow fields in the enclosure are symmetric about the vertical centerline. The detailed physical interpretations have been provided for the reported results. Further, the increase in the power-law index means a rise in viscosity and a decrease in thermal energy transport for other constant parameters. The outcomes also specify that the intensity of circulation and heat transfer enhances with the increase of Rayleigh number and size of the localized heater. Finally, though, a rise in the size of the confined heat source enhances the rate of total thermal transport, it does not change the trend of fluid flow and local heat transfer rate.

Simulation of vortex characteristics in a planar ψ-shaped branching microchannel with lattice Boltzmann method

2020 ◽  
pp. 2150036
Author(s):  
Kai Feng ◽  
Huichen Zhang
Keyword(s):  
Reynolds Number ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Negative Impact ◽  
Current Model ◽  
Lattice Boltzmann Model ◽  
Power Law Fluids ◽  
Branching Angle ◽  
Recirculation Length ◽  
Power Law Index

The vortex in the branching microchannel enhances the mixing and heat transfer performance. To investigate the vortex intensity quantitatively, a lattice Boltzmann model for incompressible power-law fluid is developed by setting the range of lattice viscosity (0.001 [Formula: see text] 1). The validation of the current model is carried out by modeling the vortex in a T-shaped branching channel and the Poiseuille flow of power-law fluids. Then the vortex intensity in the [Formula: see text]-shaped microchannel is numerically studied in terms of Reynolds number, branching angle and power-law index. The result indicates that both the recirculation length and height increase with the increase of the Reynolds number. The branching angle has a negative impact on the recirculation length, and it has little effect on the recirculation height. The influence of the power-law index on recirculation length and height depends on the Reynolds number.

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