成像測量圓筒內部球體在水中轉動的情況

Internal Imaging Measurement of Immersed Granular Flows in a Rotating Drum

戴永惠(Yung-Hui Tai)

指導教授 ： 卡艾瑋

國立臺灣大學/工學院/土木工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01173

摘要

本文是利用一個在水下旋轉的圓筒及搭配粒子影像分析（PTV）的方法來模擬水下崩塌的實驗。其為了方便觀察顆粒內部運動及流場變化，除了利用雷射切頁外，還特別使用折射率接近的壓克力球及特殊化學液體（para-cymene）。在二維的狀況下，是將雷射固定在同一位置去切單個剖面。而在三維的部份，為了加快掃描速度及在短時間內獲得圓筒完整的厚度，故使用一個特殊的旋轉工具，並成功將影像轉換至三維座標系統。進而取得，當顆粒數量是固定的狀況下，不同的圓筒轉速對其二維及三維流場變化及顆粒運動情形。

關鍵字

旋轉圓筒 ； 水下崩塌 ； 旋轉工具 ； 三維座標系統

並列摘要

In this thesis, immersed granular avalanches in a rotating drum are studied experimentally using particle tracking velocimetry (PTV). To observe internal motions, refractive index matched solid and liquid materials are used. A laser light sheet is then used to illuminate slices through the flow. Two-dimensional motions of both solid and liquid motions in the center plane are measured using a stationary laser light sheet. We then seek to measure the full three-dimensional positions and velocities of the solid grains by scanning the flow volume using a rotating light sheet. Fast scans are obtained using a special rotating mirror device, and calibrated in 3D using a trilinear coordinate transformation. The effect of varying the drum rotation rate is examined. Measurements in 2D and 3D are obtained for avalanches of 1500 spherical grains.

並列關鍵字

rotating drum ； immersed granular avalanches ； a special rotating mirror device ； trilinear coordinate transformation

參考文獻

Armanini, A., Capart, H., Fraccarollo, L.and Larcher M. 2005 Rheological stratification in experimental free-surface flows of granular–liquid mixtures. J. Fluid Mech. 532, 269–319.

Capart, H., Yong, D. L., Zech, Y. 2002 Voronoï imaging methods for the measurement of granular flows. Exps. Fluids 32,121-135.

Chi, T. A. 2007 Laser halo measurements of solid-liquid two shape flows. Master thesis, Department of Civil Engineering, National Taiwan University,Taipei,Taiwan.

Chou, H. T., Lee, C. H. 2009 Cross-sectional and axial flow characteristics of dry granular material in rotating drums. Granul. Matter 11, 13-32.

Doppler, D., Gondret , P., Loiseleux ,T., Meyer, S. and Rabaud, M. 2007 Relaxation dynamics of water-immersed granular avalanches. J. Fluid Mech.577, 161-181.