軟球粒子在球形孔洞的沉降現象

Sedimentation of a Soft Particle in a Spherical Cavity

黃子豪(Tzu-Hao Huang)

指導教授 ： 李克強

國立臺灣大學/工學院/化學工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00184

摘要

本研究乃是討論軟球粒子在球形孔洞中的沉降運動。軟球粒子系統由於其特殊的物理結構，可以對於生物細胞及高分子有更加貼近的描述。對於非線性的流場、電場及濃度場之方程式耦合，先經過假設之後線性化此三大主控方程式，再利用假性光譜法來進行數值模擬。

當軟球層所帶固定電荷(Qfix)為正電荷時，將會使粒子的沉降運動有減緩的現象；反之，當軟球層所帶固定電荷為負電荷時，沉降速度會有加快的情形發生。當電雙層厚度很薄時，沉降電位將不會因為軟球層固定電荷(Qfix)的正負大小有所影響，會趨向一定值。在高表面電位下，沉降速度受到加速或減速的情形則會更明顯。軟球所占體積分率(H)越大，其沉降速度受到極化效應影響而下降的程度也越少，沉降電位則越高。

關鍵字

沉降電位 ； 沉降速度 ； 球形孔洞 ； 軟球

並列摘要

In this study, sedimentation of a soft particle in a spherical cavity is investigated. Due to its particular structure, soft-particle systems can be used to depict biological cells and polymers appropriately for widely application. These non-linear hydrodynamic, electrical potential and ion-conservation equations are coupled. After some assumptions, these equations are linearized and calculated by pseudo-spectral method simultaneously.

If the fixed charges in the ion-penetrable layer (Qfix) are positive, the sedimentation will be retarded； if there are negative charges in the ion-penetrable layer, the sedimentation velocity will be accelerated. As the electrical double layer is very thin, Qfix have no influences on the sedimentation potential; as a result, the sedimentation potentials are all near a constant. When the surface potential is large, the accelerations or decelerations of sedimentation velocity are more notable. The larger the volume fraction (H), the reduced range of sedimentation velocity by the polarization is getting smaller, and the sedimentation potential is larger.

並列關鍵字

soft particle ； cavity ； sedimentation velocity ； sedimentation potential

參考文獻

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