(490h) Non Newtonian Fluid Flow through Converging Diverging Channel

Various fluids such as blood, polymer solutions and surfactants can also be modelled as Non-Newtonian fluids to study their flow characteristic. Numerous models have been extensively studied to derive the flow behavior of these fluids. The power law model is one such model which is widely used to model the behavior of Non-Newtonian Fluids. Complex fluids can also be modelled as a mixture of two power law fluids with different power law indices. Thus, it is important to develop methods which provide fast and reliable simulation results for Non-Newtonian Fluids. Lattice Boltzmann Modelling (LBM) is one such method increasing in popularity in recent times. Flow of shear-thickening fluid in converging-diverging channel is done to understand its flow behavior in micro-channels which can be modelled as a converging-diverging channel. We aim to find if there is a maximum pressure drop for any channel angle.

The main objective of this work is to create a comprehensive model and code using Lattice Boltzmann Modelling to simulate the flow of shear-thickening power-law fluids in Converging-Diverging channels. We study and compare different flow characteristics such as velocity, strain rate and pressure drop.

Flow of shear-thickening power-law fluid in a converging-diverging channel was investigated using Lattice Boltzmann Modelling. A code was developed using single relaxation time (SRT-LBM) and incorporating non-Newtonian fluid flow. Pressure drop in a converging-diverging channel was found to increase with increase in the angle of the tube. Higher pressure drop was observed for higher power-index value with similar effective viscosity. Finally, a variable-n power-law fluid flow was simulated, and its flow characteristics were compared with its single-n constituents. Higher strain rate was observed in a variable-n fluid that a single-n power-law fluid. Velocity profile characteristics for a variable-n fluid was observed to be a mixture of its constituent fluids velocity profiles.