顆粒在流動過程的混合/分離行為在許多工業應用中常常可見，且經常是極需解決的議題。然而顆粒的偏析分離與混合雖然是很直觀的現象，但其內涵的物理機制卻非常複雜。因此仍有許多議題待釐清，也需要進一步利用實驗量測與理論模型預測去做驗證。此外由於具有不同性質之顆粒於不同載具、不同驅動力下，所產生的顆粒分離機制亦會不同，因此本計畫將針對粉顆粒分離混合行為進行為期三年的研究。第一年度計畫將針對以雙壁旋轉鼓做為顆粒載具，並以實驗方式分別針對在不同的填充率以及轉速下，探討旋轉鼓中顆粒之尺寸分離現象。藉此研究可以了解當填充率極高的情況下，因重力或離心力影響所造成之顆粒分離現象的物理機制與原理。第二年度則將針對微小尺寸粉末之含量對於整體大顆粒崩塌流動行為之影響，計畫也將透過進行一系列顆粒潰壩崩塌實驗去探討此大顆粒與小粉末分離之研究議題，小粉末所造成的潤滑效應，也在此年度進行深入探討。第三年則將探討在振動顆粒床中的顆粒尺寸分離效應，我們透過加入一大顆尺寸之顆粒（或常稱入侵顆粒）於小尺寸顆粒振動床系統之實驗，探討此大顆粒在振動驅動力下，產生巴西豆效應之尺寸分離現象，並研究分析在顆粒床中上升分離之速率。 ;The mixing/segregation behavior of granular flow is a very important research topic, and it is also a critical issue in many industrial applications and needs to be solved. Although this phenomenon is very intuitive, the physics and mechanisms are very complicated. Therefore, there are many issues still need to be clarified, and it is necessary to conduct the experimental measurements and theoretical predictions for further investigations. In addition, in a granular system, when different-properties particles are under different carried vehicles and different driving forces, the segregation mechanisms are also different. Therefore, this project will conduct a three-year study on the segregation and mixing behavior of powders/particles. The first year of the project will conduct experimentally studies on the granular size segregations in a double-walled rotating drum. The effect of filling degree and rotation speeds of the rotating drum are discussed in this year. The results in this year can help us understand the physical mechanism and the principle of particle segregation phenomenon when the system in an almost fully filled. The influences of gravitational and centrifugal forces on the segregation in this system will also be discussed. The second year of the project will discuss the effect of the content of fine powders on the collapse behavior of large particles by conducting a series of granular collapse experiments. Due to the simple setup and rich behavior, the granular column collapse has been studied experimentally and numerically by several authors. However, the lubricate effect of fine powder on such granular collapse has received relatively less attention and remains an issue worthy of examination. Therefore, this issue will be investigated in-depth in this year. The third year of the project will investigate the effect of granular size segregation in a vibrating bed. The size segregation phenomenon under the Brazil nut effect will be discussed by immersing a large-sized particle (intruder) in to a small-sized-particle vibrating bed system. The rising time of the large-sized particle will also be measured and analyzed to quantify the strength of the segregation.
