Experiment Research And Numerical Simulation Of The Laminar Flow In The Microchannels Between The Two Parallel Planes

This dissertation work includes two parts: One is two-dimension Micro-particle image velocimetry (MPIV) measurements of the flow field between two parallel planes .The other is numerical investigation of the laminar flow within the two infinite parallel planes, which has different roughness, by using universal CFD software.The basal theory and some key technique are discussed in this paper. The differences between Micro-PIV and traditional PIV in the choice and seeding of the particle, the volume illumination the image capture system, is explained. Some suggest about key aspects of Micro-PIV technique is given.The lab table for the measurement of flow between two parallel planes is designed. The measurement of the laminar flow between two parallel planes that the distance between the two parallel planes is 2.25mm and 1mm is performed. Compare the measured velocity profile and analytical solution of Poisoeullie flow shows a good agreement within the most part of the measured region, while the value of the former is higher near the wall resulting from the combined effects of strong flare light and velocity gradient polarization. These results validate that Micro-PIV is well suitable to investigate fluid flow in the microchannels in condition that the right seeding particle, microscope system and illumination pattern is selected.The numerical simulation of the flow between two parallel planes that the distance of two parallel planes is 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm and 2.25mm by using the universal software. The numerical results are compared with the experimental results when the distance of the two planes is 1mm and 2.25mm. It is validated that the numerical methods can absolutely predict the flow in the microchannels. The flow field around the roughness and the pressure drop of midline along flow direction are analyzed. It's found that the range of the pressure drop change relate to the magnitude of relative roughness, the distance between twoparallel planes, the Re number and ratio of the size of roughness and the distance between two roughness.