開發與應用多孔性高分子壓力螢光感測塗料於穿音速AGARD-B流場量測

The Development and Application of Mesoporous Pressure Sensitive Paints on Transonic Flow Measurements with AGARD-B Model

林筠芳(Yun-Fang Lin)

指導教授 ： 黃智永

國立清華大學/工學院/動力機械工程學系/碩士(2020年)

摘要

本研究旨在利用自行開發的壓力螢光感測塗料(pressure sensitive paint; PSP)搭配溫度螢光感測塗料(temperature sensitive paint; TSP)進行AGARD-B模型於穿音速流場中的機翼全域性表面壓力分佈量測，目的在於探討穿音速流中AGARD-B的流場現象以及壓力螢光感測塗料應用上的優點與限制。AGARD-B模型為標準風洞校驗模型，模型由機鼻、機身及機翼所組成且各部位尺寸皆以機身直徑D = 48 mm定義，實驗中測試模型的攻角(angle of attack，AOA)實驗參數如下：0 °、2 °、4 °、6 °、8 °，穿音速風洞自由流速度設定為馬赫數(M)0.83，雷諾數(Re)為15.1 × 〖10〗^6 (per meter)。
由於本研究主要針對AGARD-B模型三角薄翼部分進行表面壓力分佈的量測，傳統的壓力管量測方式較難於薄翼結構進行實驗，且其量測範圍僅限於有埋壓力管處無法準確抓取關鍵流場現象如二次渦旋，故本研究利用以高分子材料與多孔性中空顆粒調配的壓力螢光感測塗料進行壓力分佈量測實驗，同時藉由流場可視化了解流場二次渦旋現象。所使用之壓力螢光感測塗料配方的壓力靈敏度為0.59 %/kPa，溫度相關性為–0.95 %/℃。然而壓力螢光感測塗料同時會受環境壓力與溫度變化而發生螢光亮度的改變，因此本研究一併採用市售溫度螢光感測塗料進行表面溫度分佈的量測，再透過溫度數據對壓力螢光感測塗料的壓力校正曲線進行修正，以消除風洞試驗中壓力螢光感測塗料受溫度的影響。
AGARD-B模型屬於三角薄翼機型，隨著模型攻角的增加機翼上、下翼面的壓差會逐漸加大，使氣流由底部向上捲起於上翼面翼前緣處形成渦流，在高渦度運動的渦流下方機翼表面會呈現極低壓帶，在翼後緣附近渦流位置兩側區域則受渦旋結構影響而較為高壓。由機翼最前端沿翼前緣向後、向外發展的二次渦旋當攻角增加至4 °後出現於上翼面，二次渦旋會隨著攻角增加而持續發展使最低壓位置的壓力值更趨下降且渦流位置會逐漸向翼根移動。實驗數據與模擬數據間的誤差僅3.840 kPa，小於實驗不確定性6.51 kPa。隨攻角由0 °上升至8 °，升力係數(C_L)由0增加至0.476，與模擬數據非常接近，而阻力係數(C_D)則由0.02增加至0.059，與模擬數據的偏差量約為0.03 (C_D)。
綜觀實驗結果，本研究成功將自行開發調配的多孔性高分子壓力螢光感測塗料應用於穿音速AGARD-B模型的表面壓力分佈量測與流場可視化，也證實溫度修正對壓力螢光感測塗料量測技術的重要性。沿翼展方向與沿翼弦方向的壓力量測結果與ANSYS數值流體力學模擬結果比對後呈現高度相符，透過實驗數據計算所得之升力係數及阻力係數趨勢也與數值流體力學及相關文獻相符，證實壓力螢光感測塗料應用於穿音速流場量測的可行性。

關鍵字

AGARD-B流場 ； 三角薄翼流場 ； 壓力螢光感測塗料 ； 溫度螢光感測塗料

並列摘要

This study aims to analyze the flow field over an AGARD-B test model with experimental techniques of pressure sensitive paints (PSP) and temperature sensitive paint (TSP). The AGARD-B test model is a standard wind tunnel calibration model with a pair of delta wing. Experiments were carried out in a blowdown-type transonic wind tunnel at different angle of attack varying from 0 to 8 degrees with the freestream Mach number of 0.83 and Reynolds number of 15.1 × 〖10〗^6 (per meter).
Unlike the conventional pressure tap measurements, PSP can provide the global pressure distribution on the model surface and can be applied on complex geometry. Due to the temperature dependency on PSP measurements, both PSP and TSP were applied in this study to measure the pressure and temperature simultaneously and the PSP data was corrected using the temperature data from TSP measurements. The polymer binder of RTV-118 and silica mesoporous particles were used to prepare porous PSP. The pressure sensitivity of PSP was 0.59 %/kPa and the temperature dependency of PSP was -0.95 %/℃. The commercial available UNT-400 was chosen as the TSP for the experiments, and the temperature sensitivity of TSP was -1.28 %/°C.
As the angle of attack increasing, the pressure on the lower surface of the wing was increased and higher than the pressure on the upper surface. A pair of vortices generated around the leading edge due to the pressure difference between the bottom to the top and these vortices created a strong suction on the upper surface starting at the leading edge. The strong suction introduced by the vortices created low pressure regions on the upper surface and enhanced lift force. The low pressure region generated by the vortices can be clearly identified on the upper surface at 4 degrees angle of attack. The secondary vortex would gradually reduce the pressure on the upper surface of the wing and the location of the vortex would move from the leading edge to the wing root while the angle of attack increasing over to 6 degrees. The lift coefficient raised from 0 to 0.476 as the angle of attack increasing from 0 degree to 8 degrees while the drag coefficient rising from 0.002 to 0.059.
In this study, porous PSP was successfully developed and applied to the surface pressure measurement and flow field of AGARD-B model in transonic flow was quantitatively visualized. The pressure distribution along the span and chord directions were agreed with the simulation results from ANSYS commercial computational fluid dynamics software. The lift and drag coefficients calculated through the experimental data were also in good agreement with the numerical results and the data reported by literatures.

並列關鍵字

AGARD-B flow ； delta wing flow ； pressure sensitive paints ； temperature sensitive paints

參考文獻

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