Numerical Simulation Of Non-Newtonian Power Law Fluid And Blood Flow In Multiple Microchannels

Microfluidic technology refers to the technology of operating and controlling complex fluids at the microscale.It is a new research field developed on the basis of instrument science and technology,microelectromechanical systems and other disciplines.This paper selects micro-channels with various cross-sectional shapes,sizes and structures,based on the assumption of fluid continuity,and uses numerical simulation methods to study the flow characteristics of non-Newtonian power-law fluids and blood flow.First,three-dimensional models of microchannels with different cross-sectional shapes are established,and the non-Newtonian power-law fluid in the microchannels is numerically simulated.Studies have shown that the length of the velocity entrance section of the circular cross-section microchannel is the shortest,and with the increase of the power law exponent,the non-Newtonian fluid reaches the fully developed state more quickly;The temperature field distribution in the microchannels with different cross-sectional shapes is roughly the same,and the heat transfer center is at the same position as the cross-sectional center,and the distribution of the temperature field in the microchannel is more likely to heat up due to the influence of the sharp corner area.Then,in view of the cross-sectional size,structure and other factors affecting the flow of non-Newtonian power-law fluid in the microchannel,a rectangular crosssection microchannel was selected,and the flow and heat transfer characteristics in the rectangular microchannel were studied by numerical simulation.The rectangular microchannel was discussed.The cross-sectional aspect ratio,hydraulic diameter,structural changes and other factors bring the influence.The study found that with the same cross-sectional aspect ratio,as the hydraulic diameter of the microchannel increases,the overall pressure drop decreases,the area of the low-temperature region increases,and the maximum temperature value rises;under the same hydraulic diameter,the microchannel decreases the aspect ratio improves the heat transfer capacity of the microchannel and improves the uniformity of temperature distribution in the microchannel.Finally,based on the Carreau non-Newtonian fluid model,a numerical simulation of the blood flow in the human aorta and its branch vessels is carried out to study the unidirectional fluid-solid coupling between the blood and the elastic wall,and the deformation of the blood vessel and the dynamic characteristics of the blood flow are carried out analysis.The results show that the entrance and exit of the artery and the bifurcation are the positions where the flow rate,pressure,and wall shear force change most drastically in a heartbeat cycle,and are also the locations where the highest pressure,flow rate and maximum deformation occur in a heartbeat cycle.Therefore,the entrance and exit of the aorta and the bifurcation are closely related to the initial position of cardiovascular disease.The research results can be used to guide the transport mechanism and flow characteristics of non-Newtonian power law fluids in a variety of microchannels,and have certain reference significance for the hemodynamic analysis of non-Newtonian blood flow in the microchannels.