葛煥彰2006-07-252018-06-282006-07-252018-06-282002-08-31http://ntur.lib.ntu.edu.tw//handle/246246/9301膠體粒子與孔隙流體系統受到外界所 施加的電位、溫度、或溶質濃度梯度的驅 動，會產生微小粒子於一連續相中之輸送 行為和流體在多孔介質中的流動行為，此 二種現象分別稱為”泳動”和”滲透流”現象。 擴散泳是由於膠體粒子受到溶液中溶質濃 度梯度的影響而進行的泳動，擴散滲透則 是流體在多孔介質中受到溶質濃度梯度的 影響而造成的流動。本文以理論解析，在 對稱電解質溶質濃度梯度下，圓柱形粒子 均勻懸浮系統中的擴散泳和擴散滲透速 度。外加溶質濃度梯度為一常數且相對圓 柱軸心可為任意方向。 本文分別呈現粒子周圍電雙層為薄層 和任意厚度的兩種情況。在薄電雙層的研 究中，係假設電雙層厚度遠小於粒子的半 徑，但卻考慮擴散離子在此薄電雙層內的 極化效應。在任意厚度電雙層的研究中， 則電雙層厚度相對於粒子的半徑可以是任 意值，但只有考慮粒子表面為低電荷密度 (低表面電位)的情況。本文使用單元小室 模型考慮粒子之間的交互作用，可導出整 體流體的擴散滲透速度和平行排列圓柱多 孔介質孔隙度的函數關係，並且以解析型 式表示出來。對圓柱具有任意厚度電雙層 時，擴散滲透速度解析式只適用至圓柱表 面電荷密度或表面電位值為二階的情況。 將圓柱之薄電雙層研究與任意厚度電雙層 研究的擴散滲透可動度結果進行比較，亦 可以看出當電雙層厚度參數a k 值小於20 時，薄作用層研究的結果會有明顯的誤差。Driven by applying an electric potential, temperature, or solute concentration gradient, the transport behavior of small particles in a continuous medium and the flow behavior of fluids in porous media at low Reynolds numbers are the phenomena known as “phoretic motion” and “osmotic motion”, respectively. Diffusiophoresis is the motion of colloidal particles in an applied interactive solute concentration gradient and diffusioosmosis is the fluid flow induced by the solute gradient in the porous medium. In this project, the diffusiophoretic and diffusioosmotic motions are analytically studied in gradients of a symmetric electrolyte solute in a homogeneous suspension of a circular cylinder. The imposed solute concentration gradient is constant and can be oriented arbitrarily with respect to the axes of the cylinders. Analyses for both thin and arbitrary electric double layers surrounding the particle are presented. In the thin-double-layer analysis, the thickness of the double layer is assumed to be small relative to the radius of the particle, but the polarization effect of the diffuse ions in the double layer is incorporated. In the arbitrary-double-layer analysis, the double layer may have an arbitrary thickness relative to the radius of the particle, and only the particle surface with a small surface charge density (or zeta potential) is considered. The effects of interaction among individual particles are taken into explicit account by employing a unit cell model. Analytical expressions for the diffusioosmotic velocity of the bulk fluid as functions of the porosity of the ordered array of cylinders are obtained for various cases. For cylinders with an arbitrary double-layer thickness, the expressions for the diffusioosmotic velocity are obtained in closed form correct to the second order of their surface charge density or zeta potential. A comparison of the results of the diffusioosmotic mobility obtained in the thin-layer analysis and in the arbitrary-layer analysis for the cell model is made. Again, the diffusioosmosis results predicted by the thin-double-layer analysis can be in significant errors when the value of the electric double layer thickness parameter ka is less than about 20.application/pdf218738 bytesapplication/pdfzh-TW國立臺灣大學化學工程學系暨研究所圓柱粒子擴散泳擴散滲透小室模型Cylindrical particleDiffusio-phoresisDiffusioosmosisUnit cell modelreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/9301/1/902214E002019.pdf