Laser speckle test system

Abstract

The invention discloses a laser speckle testing system used for measuring the movement velocity of nano-particles in nano-fluid. The system is characterized in that the irradiation mode of a light source and the receiving mode of a recording device are improved according to the optical character of the nano-particles. An extender lens system is used for two-dimensional expansion of laser beam to form the flowing nano-particles that are irradiated by a surface light source; the recording device is arranged on the light path which positively faces to the incident light direction at the other side of a transparent pipe of the tested nano-fluid according to the rayleigh scattering characteristic, so that the speckle image of the nano-particles is recorded clearly; the laser speckle testing system of the invention is not only used for measuring the movement of the nano-particles in the nano-fluid, but also applicable to the movement measurement of micron particles; the system has simple structure and wide range of usage, and can be widely applicable to speckle measurement of the movement velocity of fluid.

Description

a technical field [0001] The invention relates to a laser test system, in particular to a laser speckle test system for testing the moving speed of nanoparticles in nanofluid. Two background technology [0002] As early as 1977, speckle measurement technology was introduced into the field of fluid mechanics to measure the velocity of flow field, which is called laser speckle velocimetry, and gradually developed into particle image velocimetry. The application is particularly extensive. The testing principles of the laser speckle testing system and the particle image testing system are similar. They both indirectly measure the transient velocity distribution in the flow field by measuring the displacement of the tracer particles within a known short time interval. The difference is the magnitude of the tracer particle concentration. When the concentration of scattering particles is small, the distance between the particles is far away, and there will be no interference betw...

AI Technical Summary

Problems solved by technology

One of the characteristics of Rayleigh scattering is that the scattered light is very weak. A single nanoparticle cannot form a particle image. It must illuminate a large number of particles, and then the scattered light of a large number of particles can be interfered and superimposed to form a clearly visible speckle image. Therefore, the existing particle The image velocimetry system is limited by the system itself, no matter from the illumination mode of the light source and the recording mode of the speckle pattern, it is not suitable for the measurement of the movement of nanoparticles in the flow field, and the system needs to be redesigned and improved

Images