抄録
Needle valve is widely used for flow control in industry. Changing the flow area, which is a circular gap between the cone-shaped core and valve body, the discharge of flow through the needle valve can be controlled. The gap of needle valve is less than one hundred microns, which can be blocked up slowly by the tiny particles in the fluid for a long time. In this paper the quantitative relations among the reduction of discharge, size of particle, concentration of particle and opening of needle valve were studied. These results are worth for designing a new style lubricator with high precision. The particle's movement in the narrow slit was also' analyzed in theory and visualization.
