本論文以發展低成本之Moiré 干涉技術為主,用以量測在自然對流中的測試物之二維溫度分布。實驗架設使用一個單色紅光之LED燈作為燈源,其 燈源光譜約為625-635 nm。在實驗過程中,單色LED燈發散光源起初先經過球透鏡,然後利用球透鏡將LED燈發散光源聚焦成一個點光源,並將此點光源放置在一直徑406 mm 及f/4.5之拋物面鏡的焦點上以產生平行光,此平行光經過測試區及兩個由雷射印表機列印之頻率皆為254 lpi 的光柵,在光柵後方有一台CCD相機用來抓取變動之條紋。根據 Moiré理論得知,變動之條紋的移動量代表著其位置的溫度高低。本研究成功地量測二維熱流在自然對流下的溫度分布,在測試物為40-95℃ 的垂直均溫板、60 W燈泡及燃燒的蠟燭,使用Moiré 干涉技術及熱電偶可以得到最小誤差約為5$\%$。本論文並同時開發其他低成本的定性與定量光學量測技術,以定性量測的架構發展出Schlieren、Micro Schlieren、全尺寸Schlieren(FSS)、高精度光學影像偏移偵測器及光斑偏折流體顯像技術;以定量量測的架構發展出光斑偏折技術。以上技術發展得到傳統彩色Schlieren之遮光率在90%有較佳的成像效果,其可辨識最小瓦斯洩漏孔徑 ϕ 27.5 um搭配洩漏壓力 5 torr ,其洩漏率 0.011 ml/sec。另外,本論文並且成功地將自動化光斑偏折技術應用在微細孔氣流與熱流洩漏偵測上。
This article develops low cost Moiré deflectometry for two-dimensional temperature measurement in free boundary environment. Experimental setup uses a red monochrome LED lamp with wavelength range of 625-635 nm as light source. In process, the light first runs through the convex lens and then propagates to the parabolic mirror with diameter of 406 mm and f/4.5 for generating the parallel light. The parallel light further propagates to test object and through two gratings with both pitch 254 lpi, printed by laser printer. Behind the two gratings, a CCD camera is applied to capture the image, the distorted fringes. Based on the Moiré deflectometry theory, the two-dimensional temperature distribution in free boundary environment can be determined in terms of the captured fringe shift analysis. This work has successfully measured the two-dimensional temperature distribution in free boundary environment with heat source models of 40-95℃ vertical wall, 60 W light bulb, and burning candle flame. The measured temperature deviations between Moiré deflectometry and thermocouple thermometer are all less than 5$\%$. This study has also developed another low cost qualitative and quantitative optical measurement techniques. The qualitative techniques consist of Schlieren, Micro Color Schlieren, Full-Scale Schlieren, optical spot deflectometry and high resolution optical image deviation detector; the quantitative technique is optical spot deflectometry. The results show that the Color Schlieren technique with blockage of 90$\%$ obtains the best sensitivity and can detect the tiny hole LPG flow behavior under ϕ 27.5 um with pressure difference of 5 torr. The flow rate is 0.011 ml/sec. Finally, this work successfully combines the optical techniques studied in CCT Lab. to evolve the real-time and automation optical spot deflectometry software for detecting leaked gas flow, heat flow, public security, and scientifical research flow fields.