Measurement of Three-Dimensional Flow Field in a Micro-Rectangular Channel Using a Color Micro Particle Image Velocimetry

• Main Authors: Li, Tzu-Hao, 李子豪
• Other Authors: Sheen, Jyh-Jong
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/12101488301600853997

碩士 === 國立臺灣海洋大學 === 機械與機電工程學系 === 103 === In this thesis, a color micro particle image velocimetry (PIV) with a dark field condenser was demonstrated. With the off-axis illumination, there is no nood for an optic filter, and therefore, the color of the tracking particle can be used. As a result, it is able to use RGB light emitting diodes (LED) and a consumer camera instead of a double pulse laser and a PIV camera. When observing a flow field, the camera shutter is fully open, and a photo is exposed by flashing RGB color lights sequentially. The color particle image can further be separated into three RGB particle images. These three particle images can be used for the calculation of the PIV flow field. The flow field of a rectangular microchannel was investigated and the result was examined by its analytical solution. As the off-axis illumination has a conical optic path and RGB lights have different indexes of refraction, it will produce a bias error at different points of the microchannel. By constructing a bias-error model, this error can be reduced enormously. The three-dimensional movement of the wafer stage can be controlled Z-axis direction, so that different particles in a microfluidic channel height of the image are in focus at the optical path taken to achieve consistent image brightness and clarity of purpose. With the volumetric flow of 1 l/min, the analytic maxmum flow velocity of Square channel is 3.503 mm/s ; the experimental result is 3.484 mm/s with the error of 0.5% ；the analytic maxmum flow velocity of Rectangular channel is 1.594 mm/s ; the experimental result is 1.575 mm/s with the error of 1.2%. To further increase the flow accuracy near the channel wall, different interrogation windows were investigated. In consequency, the normalized error was reduced to 0.08 and 0.22 Key point : color micro particle image velocimetry、dark field condenser、The three-dimensional movement of the wafer stage、rectangular microchannel