Development of a PIV system using a laser-diode

Abstract

A low cost PIV (Particle Image Velocimetry) was developed for characterization, visualization and quantification of a flow test section. Optical devices are common nowadays in metrology, in fluid-flow measurement and studies of flow around structural models or industrial facilities in wind tunnels. The advantages of the optic devices are high resolution, precision, fast response time and, most important, it is not intrusive. The PIV system developed is composed by a quasi-continuous laser-diode with nominal power up to 100 W, monochromatic at 800 nm wave length. An orthogonal lens set defines the width and thickness of the light screen in the test section. Image acquisition is made by a CCD camera. Acquisition and processing image software was developed in C++ and Matlab. The flow field velocities are determined by processing successive images using cross correlation. Analysis of fluid flow around 1 and 2 cylinders, in parallel, were conducted. The tests were conducted in water seeded with micro-spheres with 30 μm mean diameter. The analysis were conducted with velocities of the order of 0.15 m/s, the optical window dimensions was about 100 mm x 150 mm. The results show that the PIV prototype is working even though further development is necessary.