摘 要
混合顆粒體在振動床中，會有大顆粒向上升，而小顆粒向下沈的分離現象，本文即是探討在二維狀態下影響振動床粒子分離機制的原因。由於振動床的分離現象在實驗中極易受到各種因素變化的影響；因此，本文討論的方向有三部分。第一部分為粒徑比，在二維的狀態下，不同直徑大小的銅圓盤與分離所須時間之間的關係及在不同加速度下，對分離結果的影響與時間之關係。實驗結果顯示：當大圓盤直徑愈大，其所須之分離時間愈短。反之當大圓盤之直徑愈小時，其所須之分離時間愈長，可是當大圓盤直徑超過臨界值時，分離時間並未改變。同時，在不同的加速度下，臨界值也各有不同。第二部分則是質量，在粒徑比固定的情況下，外徑相同但內徑各異的銅圓環與分離時間之間的關係。結果指出：質量對於分離現象有影響但不顯著。第三部份則為密度，大小相同但密度不同的圓珠與分離時間的關係。實驗結果顯示：與背景粒子的密度差異愈大者，所需分離的時間也愈短。而在迴流強度之影響方面，加速度愈大，迴流強度愈強，分離效果愈佳，所須的分離時間愈短。

The segregation phenomena in vibrating bed is rich and attracted by many researchers.The larger particles tend to move upwards and the smaller ones move downwards due to the particle reorganization.There are three facts researched in the thesis,including diameter ratio、reduced mass ratio and density ratio.The results show that the velocity of the lagre disk increases with the diameter ratio and can’t increase anymore after the critical value.The mass doesn’t have great influence on srgregation when the diameter ratio fixed.Finally,the more less density,the more ascent velocity.

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