2008-08-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/664682摘要：固體液體二相混合體常見於現今的工業製程及大自然環境中：從石油產業的鑽井疏通、水泥或食品藥物之製作運送及封裝，到晶圓磨潤、精密加工或LED的填充及鍍膜；由山崩、土石流、河川淤積，到魚群運動及血管血球運動相關的醫學工程。固液介面上不可忽略的交互作用，改變混合體的本固關係式，造成二相混合體有別於單相連續體的運動行為。因此，僅管重要，現今對此種異相介質混合體的運動仍只有片面的了解。為達更有效率的系統設計、更精準的二相流控制，或對自然災害作主動性的預測及防治、突破生醫科技技術，我們對相關固液混合體的物理力學特性，實應有所掌握，其受外力作用下的動態反應，更應全面性探討。 鑒於當今研究均著重在混合體的穩態本固關係式，甚少涵蓋其動態特性，本研究將針對固液二相流的非穩態行為做系統性的探討。此外，異於實驗室裡慣用的單一固體顆粒，實際應用上的二相流混合體通常由數種固體顆粒所組成，因此，本計劃擬藉系統的實驗觀測探討混合體的流動如何受其組成改變而影響。首重分析的參數含括：固液態密度比，顆粒尺徑比，顆粒密度或質量比。量取並歸納混合體的運動時程及堆積距離，以推算該流動狀態的特徵運動長度及時間單位，估計外界能量及動量在混合體中的傳播及損耗。此大尺度(macroscopic, flow-scale)上顯現之動態現象將與小尺度(microscopic, particle-scale)的固液體交互作用做比較，以探究二相流動態行為在顆粒及混合體兩尺度上的關聯。本計畫的最終目標，將應用實驗及尺度分析之所得，建立適用於固液二相流宏觀行為的動態模型。 <br> Abstract: A solid-liquid two-phase mixture is common in many industrial processes and natural hazard problems. From gasoline drilling, slurry transportation, to surface polishing with fine particles, a solid-liquid flow can also be found in avalanches, debris flows, and river sedimentation problems. When the two heterogeneous constituents move together with comparable inertia, the frequent particle collisions and strong solid-liquid interactions make the mixture dynamics an intrinsically multi-scale problem. Thus, the resulting bulk behaviors usually deviate from that of a pure solid or liquid mass of equal potential energy. A dynamic model that feasibly represents the bulk behavior is highly desired for better, more economic and efficient, engineering design and application. This piece of information can also be used to develop an effective warning system for nature hazard and mitigation strategies. As an attempt to answer the general big question, this research aims to investigate how a viscous and incompressible liquid constituent modifies the motion of a solid particle assembly. Unlike most of the current research that examines the constitutive relation of a solid-liquid mixture at steady flowing state, this project will focus on the unsteady bulk motion that flows down a lab-scale flume. We will estimate the characteristic time and length scales of the bulk flow through systematic experiments. The results will be examined with the well-known flow parameters—the Savage number, Sa, and the Bagnold number, Ba—that categorize the mixture dynamics by their stress distribution at steady state. New parameters that measure the unsteadiness of a solid-liquid flow will be developed. Furthermore, the obtained knowledge on bulk behavior will also be interpreted from the particle-level solid-liquid interactions. We will first estimate the particle Stokes number, St, and the particle Reynolds number, Re, which two numbers characterize different forces at particle level in a flowing mixture. In addition to the two flow parameters, Sa and Ba, the two particle-level dimensionless numbers will be employed to characterize the bulk flow. This comparison shall reveal the correlation between the microscopic solid-liquid interactions and the macroscopic mixture dynamics. The results from this sub-project shall integrate into a thorough understanding of this multi-scale two-phase flow physics. The learning will greatly assist us to develop a feasible dynamic model for a solid-liquid flow over a board flow conditions.固液二相流二相流特徵時間尺度二相流運動模型多尺度問題堆積距離Solid-liquid two-phase flow modelcharacteristic time / length scaleheterogeneous mixtureSavage and Bagnold numberReynolds and Stokes number