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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/34035

Title: 三色微質點影像測速儀之流場測量
Flowfield measurement of a Three-Color Micro Particle Image Velocimetry
Authors: Jyh-Jong Sheen
Contributors: NTOU:Department of Mechanical and Mechatronic Engineering
Keywords: 微質點影像測速儀;發光二極體;環型聚光鏡;微流體;彩色質點影像測速儀;交替色彩影像測速
Date: 2012-11
Issue Date: 2013-10-03T03:14:13Z
Publisher: 中國機械工程學會第二十九屆全國學術研討會
Abstract: 質點影像測速儀一般由光源與具雙重曝光功能之相機兩大關鍵元件所組成。其光源為滿足高時間響應、高亮度之需求,多為雙脈衝雷射。本研究之三色微質點影像測速儀(uPIV)系統,利用發光二極體(LED)之高效率、高頻率響應之特性,配合電路以脈衝模式依序驅動觸發三色發光二極體取代傳統雷射光源,降低成本與人員危險性。並運用交替色彩影像測速系統(ACIA),使曝光時間僅由LED觸發控制,無須受限於高速相機快門速度,可將消費型相機取代高價高速攝影機或雙重曝光相機。由於消費型相機感光元件濾色片採Bayer陣列,色彩還原度較差。為提高三色影像正確性,特針對三色LED波長進行影像最佳化反矩陣計算,並分析三色光源色散所造成之垂直焦點位移量及平面影像誤差量。本研究以測量直流道及具圓形檔塊之流道速度場分布,與模擬結果比較驗證其正確性。並觀察不同大小之液滴內部循環流,以及利用流體聚焦流道速度範圍較大及不穩定性週期性變化之特性,分析其速度場與加速度場,展現三色PIV系統一次量測下可獲得三層影像之優點。
In this study, a color micro particle image velocimetry (PIV) is demonstrated. Applying color high power light emitting diode (LED) as the light source and cardioid annular condenser in the microscope to preserve color information. This system is less expensive and saver than traditional PIV with double pulse laser and filter system. Utilizing ACIA (alternating color image anemometry) system let the exposure time can be control by the emission of LED instead of the shutter on high speed camera or PIV camera. Therefore we can replace high speed camera by a consumer DSLR (digital Single Lens Reflex). Because consumer camera uses Bayer filter mosaic as color filter array, the color will be less accurate. To solve this problem we use invertible matrix to optimize the wave length of our color LEDs. And we analyze the focus point displacement due to color dispersion.
Flow field of a microchannel with a cylinder was used to test the PIV system. The experimental results showed agreement with those from computer simulation software (COMSOL). Flow fields of circulation in microdroplet and both velocity and acceleration in hydrodynamic focusing were observed. In summary, experimental results demonstrate that this color µPIV system has the ability to measure both velocity and acceleration.
URI: http://ntour.ntou.edu.tw/handle/987654321/34035
Appears in Collections:[機械與機電工程學系] 演講及研討會

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