摘要或動機

The results of the thermal diffusion experimental show that the separation efficient\r
increases with increasing ΔT, but decreases with increasing Q at C₀ constant. When\r
Q is kept constant, the efficient of change ΔT are small, and the maximum at C₀ about\r
545 mg/L. The purification efficient of raw water for thermal diffusion is low.\r
And it is high energy consumption, difficult operation, and high costs. So the potential\r
of the application is low. Therefore, the vertical circulatory laminar flow apparatus\r
was developed in this study. And the separation equation of this apparatus was also\r
set up. The results of vertical circulatory laminar flow experimental show that\r
the efficient increase with increasing V, and the optimum conditions are at about\r
Q= 1.05 L/min, C₀=800±50 mg/L, and V=26 cm/min. The separation efficient of the\r
vertical circulatory laminar flow apparatus is higher than thermal diffusion apparatus.\r
And its energy consumption and costs are low, and easy to operate. Since all interior\r
moveable plates have two operation sides, so the multiple channel apparatus is application.\r
Therefore, the multiple channel apparatus can treat large amount raw water and has\r
low costs. The efficient of the experimental all are better than the theoretical\r
values that may due to: (1)the assumed partical diameter is too small,(2)the flow\r
is not real laminar flow, and (3)the end-side effect is not considerate.
\r
熱擴散實驗結果顯示在固定C₀下，分離成效隨ΔT增加而增高，但隨進料流率增加而降低。在固定ΔT下，分離效率亦隨進料流率增加而降低。固定進料流率下，增加ΔT對分離效果的影響不大，以C₀=545±10\r
mg/L時，顯現出最佳成效。採用熱擴散裝置雖對降低原水中之懸浮微粒含量效果有限，且能源需求高，造成高成本和操作複雜，不具實用潛力。為提高分離原水微粒之成率，以及簡化操作與降低成本，本研究開發垂直旋轉帶裝置來製造出上下循環水流，並導出水流與微粒於其中之流速分布式，以及頂部、底部出口之微粒濃度計算式。垂直循環轉帶實驗結果，顯示提高V值有助於降低C_t/C_b比值；Q=\r
1.05 L/min左右、C₀=800±50 mg/L下與V在26 cm/min左右，均有較低之C_t/C_b比值。垂直旋轉帶裝置分離成效明顯優於熱擴散裝置，且設備簡單、能源需求低與操作容易。由於旋轉帶之兩面均可以做為移動平板，因此不僅可以用來處理大量之高濁度原水，也能更具經濟效益。由理論與實驗結果之比較，顯示理論成效較實驗差，探討其原因可能是：(1)平均粒徑之假設值偏低、(2)流場並非全然以層流流動、(3)兩端終端效應未加考慮等。