近年來隨著微機電製程技術的蓬勃發展，在微小尺度下進行研究已成為趨勢，而在微管道中之層流流動下進行細胞篩檢更具有樣本數量需求少、檢測方便快速以及能夠精準操控流體等優點。
本論文主要利用數值模擬的方式來測試各種參數對於慣性力聚焦分離微粒之影響，相較於實驗而言數值模擬的方便性及可調性能夠更容易測試出各種會影響之參數。本團隊在矩形截面直管道中加入長方體凸起障礙物並投放直徑10μm、5μm及1μm三種不同大小的微粒，觀測其通過凸起後之運動行為再加以探討與分析。
在數值模擬計算上使用離散項模型之拉格朗日描述法來追蹤微粒在管道中隨時間與位置的變化。首先驗證過去文獻中的實驗數據以確保數值模擬的可信度，再進一步測試主要會影響微粒聚焦分離的參數並且建立基準流場，其中測試參數包括雷諾數、凸起高度、凸起長度、凸起間隔、凸起數目等。根據上述測試結果嘗試變更管道構型，探討是否會對於微粒聚焦分離達到更好的效果。

In recent years, with the vigorous development of micro-electromechanical process technology, it has become a trend to conduct research on a micro scale. Cell screening under laminar flow in micro-channels required convenient and fast detection, and precise control fluid and other advantages, etc.
This thesis mainly used numerical simulation to test the influence of various parameters on inertial force focusing and separation particles. Compared with experiments, the convenience and adjustability of numerical simulation could make it easier to test various influence parameters. Our team added cuboid steps to the rectangular cross-section straight channel and dropped three different sized particles with diameters of 10μm, 5μm and 1μm to observe their movement behavior after passing the steps and then discussed and analyzed.
In the numerical simulation, the Lagrangian description method of the discrete phase model is used to track the changes of particles with time and position in the channel. In the beginning, we validated the experimental data in the past literature to ensure the precision of the numerical simulation, and then tested the parameters that mainly affected the focusing and separation of particles and established a benchmark flow field. The test parameters included Reynolds number, step height, step length, step interval, number of steps, etc. Based on above tested results, we tried to change the channel configuration to obtain better results for particles focusing and separation.

[1]Talary, M., et al. (1999). "Future trends in diagnosis using laboratory-on-a-chip technologies." Parasitology 117(7): 191-203.
[2]Manz, A., et al. (1990). "Miniaturized total chemical analysis systems: a novel concept for chemical sensing." Sensors and actuators B: Chemical 1(1-6): 244-248.
[3]Lee, S. and S. Lee (2004). "Micro total analysis system (μ-TAS) in biotechnology." Applied microbiology and biotechnology 64(3): 289-299.
[4]Rostami, P., et al. (2019). "Novel approaches in cancer management with circulating tumor cell clusters." Journal of Science: Advanced Materials and Devices 4(1): 1-18.
[5]Chung, A. J., et al. (2013). "Three dimensional, sheathless, and high‐throughput microparticle inertial focusing through geometry‐induced secondary flows." Small 9(5): 685-690.
[6]Yamada, M., et al. (2004). "Pinched flow fractionation: continuous size separation of particles utilizing a laminar flow profile in a pinched microchannel." Analytical chemistry 76(18): 5465-5471.
[7]Takagi, J., et al. (2005). "Continuous particle separation in a microchannel having asymmetrically arranged multiple branches." Lab on a Chip 5(7): 778-784.
[8]Choi, S. and J.-K. Park (2007). "Continuous hydrophoretic separation and sizing of microparticles using slanted obstacles in a microchannel." Lab on a Chip 7(7): 890-897.
[9]Loutherback, K., et al. (2010). "Improved performance of deterministic lateral displacement arrays with triangular posts." Microfluidics and nanofluidics 9(6): 1143-1149.
[10]Segre, G. and A. Silberberg (1961). "Radial particle displacements in Poiseuille flow of suspensions." Nature 189(4760): 209-210.
[11]Amini, H., et al. (2014). "Inertial microfluidic physics." Lab on a Chip 14(15): 2739-2761.
[12]Zhou, J. and I. Papautsky (2013). "Fundamentals of inertial focusing in microchannels." Lab on a Chip 13(6): 1121-1132.
[13]Di Carlo, D., et al. (2007). "Continuous inertial focusing, ordering, and separation of particles in microchannels." Proceedings of the National Academy of Sciences 104(48): 18892-18897.
[14]何為竣 (2017). 氣控式微粒慣性力聚焦分離微流體晶片. 機械工程學研究所, 國立臺灣大學: 1-81.
[15]Berg, H. C. and E. M. Purcell (1977). "Physics of chemoreception." Biophysical journal 20(2): 193-219.
[16]S. Wereley, “Nano-Bio-Micro fluids tutorial”, Nanotech 2004.
[17]Reynolds, O. (1883). "XXIX. An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels." Philosophical Transactions of the Royal society of London(174): 935-982.
[18]Peng, X., et al. (1994). "Frictional flow characteristics of water flowing through rectangular microchannels." Experimental Heat Transfer An International Journal 7(4): 249-264.
[19]Gad-el-Hak, M. (1999). "The fluid mechanics of microdevices—the Freeman scholar lecture."
[20]Peiyi, W. and W. Little (1983). "Measurement of friction factors for the flow of gases in very fine channels used for microminiature Joule-Thomson refrigerators." Cryogenics 23(5): 273-277.
[21]Morsi, S. and A. Alexander (1972). "An investigation of particle trajectories in two-phase flow systems." Journal of Fluid mechanics 55(2): 193-208.