本研究是對五種不同鋁合金AL1100、AL2024、AL5083、AL6061、AL7005在600K、700K與800K時，其放射率的實驗分析與利用多光譜輻射測溫法(MRT)去推測溫度的結果之探討。而所使用的放射率模組為HRR、IST、IST*、IWS、WLT與WLT*等形式。目的在找出各種不同情況下都適用的多光譜放射率模組。
研究分析放射率前，先對本研究之實驗儀器量測波段可能產生之放射率誤差做分析，而中間波段放射率穩定度較高，故選擇波長從2.91μm到4.13μm做分析研究。在分析放射率上，(1)在研究波長範圍內，所有鋁合金之放射率皆呈現隨波長增加而下降的趨勢；(2)放射率在600K與700K之間放射率多為下降，而800K因為受到表面氧化與表面褪色的影響，表面顏色由亮灰色轉成暗黑色，導致整體放射率上升；(3)鋁合金中的鎂成份在高溫時會造成放射率的上升，故溫度愈高，含不同化學組成的鋁合金放射率差異愈大；(4)鋁合金在加熱2小時後，由於氧化層成長趨於緩和，以至於放射率趨於穩定。
對推測溫度而言，(1)除了IWS與WLT兩個放射率模組較差，其他放射率模組均可得到不錯的溫度推測結果，而HRR的適用性對任何情況下均較其他放射率模組為高；(2)在最小平方法的曲線迴歸上，推論出的放射率來觀察，只要推論出的放射率分布行為越接近真實放射率情況，所得到的溫度也將越準確；(3)對MRT增加所使用的波長數，發現增加波長數並不能改善溫度誤差，但若將三種輻射測溫法：單波長輻射測溫法(SRT)、雙光譜輻射測溫法(DWRT)與多光譜輻射測溫法(MRT)相比，則清楚發現增加波長數能大輻地改善推測的溫度誤差；(4)整體而言，放射率隨加熱時間的增長而達穩定可改善推測的溫度誤差；(5)對所有放射率模組的平均溫度誤差之標準差大部份都很小，再次驗證了實驗量測與MRT推測溫度的穩定性。

Experiments are conducted to investigate the surface emissivity characteristics for five different aluminum alloys, AL1100、AL2024、AL5083、AL6061、AL7005 at 600K, 700K and 800K. Six multispectral radiation thermometry (MRT) emissivity models, HRR, IST, IST* (another form of IST), IWS, WLT and WLT* (another form of WLT) are examined for the suitability of predicting aluminum alloy surface temperature. The goal of this study is to find the best MRT emissivity model which can well compensate the aluminum emissivity variations and accurately infer temperature.
Wavelength range from 2.91μm to 4.13μm is chosen because of the high stability in emissivity measurement. For aluminum emissiveity behaviors, (1)overall, emissiveity decreases with increasing wavelength; (2)emissivity decreases between 600K and 700K, but increases between 700K and 800K. Increase in emissivity is contributed to the surface oxidation and discoloration which cause the surface color change from light gray to dark black; (3) at high temperature, aluminum alloys with more magnesium constituent cause the increase in emissivity which results in a much stronger alloy effect; (4)emissivity reaches steady state after the 2nd hour due to the surface oxidation becoming fully developed.
For the examination of MRT emissivity models on aluminum, (1)most models achieve high accuracy in temperature prediction, except IWS and WLT emissivity models. HRR shows the best overall performance and stability; (2)for least-squares technique, the closer the inferred emissivity value and real one, the more accurate inferred temperature; (3)increasing wavelength number does not significantly improve measurement accuracy while applying MRT. However, compared with SRT and DWRT, MRT indeed provides better performance; (4)overall, constant emissivity value acquired with increasing heating time enhances temperature prediction; (5)results from the error analysis show good stability of experimental operation and MRT emissivity models predicting aluminum alloy surface temperature.

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