抄録
The investigation treats the coagulation of particles in oil under an a.c. electric field. The aim of the investigation is to acquire fundamental data to develop an electrostatic liquid filter with higher performance. In the present paper, the effect of the velocity gradient on the coagulation is investigated experimentally using a Couette flow formed between two coaxial cylinders. Hydraulic fluids into which silica particles having a diameter of 4μm are mixed are used as test liquids. The process of coagulation is recorded using a microscope with CCD camera and VTR at an interval of two minutes. The experiments show that a value of the velocity gradient that makes the coagulation rate maximum exists in the range of 0-10 s^<-1> and that the value depends on the magnitude of the a.c. electric field and other factors.
