液晶材料5CB物理参数对电流体动力学性能影响研究OA

In this paper,the influence of viscosity,elasticity and dielectric parameters of nematic liquid crystal 5CB on its electro hydrodynamic performance is studied by CFD method.The governing equations of dynamics including continuity equation,momentum equation and angular momentum equation are established.According to L-E and O-F theory,the relation between viscoelastic deformation and shear stress is introduced into the paper.The liquid crystal molecular director rotation angular velocity,director position,micro flow velocity,elastic free energy density and viscous shear stress are selected as the electro hydrodynamic performance characteristics.The application of DC electric field will cause nematic liquid crystal 5CB to produce stable micro flow.The magnitude and direction of the flow velocity are coupled with the rotational angular velocity of the molecular director,and are affected by the elasticity and viscousity parameters.The relaxation time can macroscopically characterize the rotation speed of the molecular director,and then determine the speed of the micro-flow.Under the comprehensive influence of the physical parameters of the medium,it is inversely proportional to the electric field intensity and dielectric parameters,and proportional to the viscousity parameters,and independent of the elasticity parameters.The numerical simulation results are experimentally verified from the flow stability and the micro-flow field profile state by using Micro-PIV method,which is in good agreement with the numerical calculation results.The conclusions of this paper can lay a theoretical foundation for the further research and application of liquid crystal microfluidic driving mode.