紋影顯像技術之定量與定性分析

Quantitative and Qualitative Analysis using Schlieren Technique

洪有成(Yu-Cheng Hung)

指導教授 ： 丁振卿

國立臺北科技大學/機電學院/製造科技研究所/碩士(2012年)

https://doi.org/10.6841/NTUT.2012.00623

摘要

本論文主要在進行紋影顯像技術之定量與定性分析研究，工作項目包括：傳統黑白與彩色Schlieren之遮光率影響探討、噴嘴氣流與噪音研究、氣體洩漏偵測、全尺寸Schlieren技術開發、抽油煙機顯像、Schlieren結果定量探討。首先進行不同遮光率對傳統黑白與彩色Schlieren成像影響，得到遮光率90%有較佳的效果。在噴嘴部分，以不同機構加在噴嘴上，藉以破壞噴嘴所產生的塊狀流，進而降低噪音。實驗以環形細孔噴嘴，成功降低噪音值24.9dB，約26.0%。在氣體洩漏偵測部分，本論文所開發的彩色Schlieren可分辨最小溫差6℃，在管內通入瓦斯氣體進行洩漏偵測實驗中，最小洩漏孔徑∅27.5μm搭配洩漏壓力5torr及洩漏率0.011ml/sec可獲得極佳顯像。另外，在全尺寸Schlieren開發中，使用模組化背投影式光源取代反射式，研究不同Cutoff Grid對敏感度的影響，結果顯示，全尺寸黑白Schlieren使用60%及全尺寸彩色Schlieren使用60-70%的Cutoff Grid可獲得較佳成像品質，此技術可分辨最小溫差為8℃、最小洩漏孔徑∅100μm搭配洩漏壓力1torr及洩漏率0.08ml/sec。在抽油煙機顯像部分，利用直徑為4cm圓形孔、頂部搭配44個圓形孔、下方搭配55個圓形孔的抽油煙機設計有較佳的抽風換氣效果。最後，本研究進一步進行Schlieren結果的溫度定量探討，得到結果的誤差值約6.3-32%之間。

關鍵字

Schlieren ； 遮光率 ； 全尺寸彩色Schlieren ； 背投影式光源

並列摘要

This article is the quantitative and qualitative analysis of Schlieren imaging including studies on shading percentage influence of knife edge for conventional black - white and color Schlieren, nozzle flow and noise, gas leakage detection, full-scale Schlieren development, flow visualization of the exhauster, and quantitative Schlieren. First, using different shading percentage knife edge for conventional black-white and color Schlieren imaging receives 90% is better. The other, adding different mechanisms on the nozzle to destroy the block flow can reduce the noise. This work uses the annular pore nozzle and reduces the noise of 24.9dB, ca. 26.0%. Another, the gas leakage detection using the LPG of pipe pressure 5 torr for gas leakage through aperture of ∅27.5μm diameter with leakage rate of 0.011 ml/sec receives the good flow visualization, where the applied color Schlieren can resolve the temperature different of 6℃. In addition, developing the full-scale Schlieren uses the modular background-oriented light source to replace the retroreflective light path and studies the influence of sensitivity by different cutoff grid. The results show that the black-white full-scale Schlieren with 60% shading percentage and the color full-scale Schlieren with 60-70% shading percentage have the better imaging quality. The developed full-scale Schlieren techniques can best resolve the temperature difference of 8℃, the leakage aperture of ∅100μm diameter and leakage rate of 0.08 ml/sec with pipe pressure of 1 torr. Moreover, the exhauster with round hole diameter of 4 cm, 44 holes on the top, and 55 holes on the bottom has the better ventilation. Finally, this study further quantitatively measures the temperature using the Schlieren and receives error of about 6.3-32%.

並列關鍵字

Schlieren ； Cutoff Grid Rate ； Full-scale Color Schlieren ； Background Oriented Full-scale Light Source

參考文獻

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