Abstract

The digital image processing method based on DPIV technique was developed to measure the gas-powder two-phase flow velocity field in laser fabrication. The powder flow image measurement process is composed of image collecting, image saving, velocity vector field and flow line group construction. Two adjacent instantaneous images of the same powder flow have been collected by CCD camera. Based on interrelated algorithm, the displacement vector field and the velocity vector field have been calculated. The data of the whole velocity field have been fitted to construct a group of flow line. Under the same process parameters as measurement, the velocity distribution is simulated by FLUENT software, and the simulated result agrees with the measured result. Results show that, the measurement method can be used to obtain the powder flow field velocity distribution online and further design the nozzle size.

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