Er Fluid, Microwave, Optical Properties And Structure Evolution Characteristics

Electrorheological fluid (ER fluid), a find of intelligent material, is usually dispersed suspension of fine solid particles with high dielectric constant into insulating liquid of low dielectric constant. Without external electric field, ER fluid shows the mechanic properties of Newton fluid, but when the external electric field is applied, ER fluid turns from the fluid into the quasi-solid and shows the non-Newton mechanic properties because of the interaction among particles. The process is momentary, controllable and revisable. In this article, the microwave transmission, optical rotation effect, structure evolution and the phase transition of ER fluids are studied. The main results are showed as follow:1. The theoretical model of microwave transmission in ER fluids is established. The basic formula of microwave transmission is induced from the Maxwell equations. The results show that the microwave transmission increases with the increasing external electric field when the dielectric constant of ER fluids is smaller than the threshold value, and, conversely, the transmission decreases with electric field.2. The transmission of microwave in ER fluids is studied by experiment. The experimental results show that the microwave transmission can be adjusted by the external electric field. When the density of ER fluid is very low, the transmission increases with the increasing external electric field, and when the density of ER fluid is high the transmission decreases with electric field. These results conform to the theoretical conclusion.3. The optical rotation in ER fluids is studied thoericaly. Considering the different attenuation in different direction and the theory of light transmission, I derive the expression of rotation angle as function of the angle 6 (between the electric vector of linearly polarized light and electric field) and other parameters on the condition of several appropriates and assumptions. The principle of with the angle 6 is simulated.4. The structure evolution of ER fluids is observed by means of the equipment that is devised and constructed. The results of experiment are in accord with thesimulation. The particles clinging to the electrodes are found stationary, which testifies the prophecy (particles clinging to the electrodes are stationary).5. Phase transition of ER fluids under external electric field is studied. Flow of ER fluids is a kind of granular matterials flows. By equivalent conduction model, the relation formula of several physical parameters is induced when the phase transition takes place. The principles of the phase transition with these parameters are simulated. The experiment is constructed and its conclusion complies with the theoretical result.