磁性奈米流體在微管道內流場特性之研究

Research on the flow characteristics of magnetic nanofluids in a microtube

黃文杰(Wen-Jie Huang)

指導教授 ： 翁輝竹

中原大學/工學院/機械工程研究所/碩士(2013年)

https://doi.org/10.6840/cycu201301072

摘要

本論文完成磁性奈米流體在微管道內流場特性之分析。主要目的在探討微管道管長(或管徑)、粒子體積分率及外部磁場強度對流體速度、壓力、壓降及流阻之影響。首先，我們完成水基磁鐵礦( )磁性奈米流體之製備與其材料性質之實驗量測與理論近似。接著，我們藉由實驗數據與理論結果之比較以驗證近似公式之合理性。最後，透過前進隱性法(MI)以數值分析磁性奈米流體在微管道內流場特性。
實驗與理論性質結果比較發現，粒子與粒子間或與管壁間之作用效應會隨著粒子體積分率增加、外部磁場強度增加或管徑減小而增加。數值流場分析結果發現，當管長增加、體積分率增加或磁場強度增加時，速度及壓力場趨於完全發展，此時壓降趨於增加而流阻趨於固定。

關鍵字

微流體學 ； 磁性奈米流體 ； 有限差分法 ； Poiseuille流動

並列摘要

This research conducts an analysis of flow characteristics of magnetic nanofluids in a microtube. The main purpose is to investigate the influences of microtube length (diameter), particle volume fraction, and the external magnetic field strength on the fluid velocity, pressure, pressure drop, and the flow drag. First, we complete the preparation of water-based magnetic ( ) nanofluids as well as the experimental measurements and theoretical approximations of their material properties. Further, we compare the experimental data and the theoretical results to verify the validation of approximate formula. Finally, we numerically analyze the flow characteristics of magnetic nanofluids in a microtube by using the marching implicit (MI) procedure.
Comparisons between experimental data and theoretical results of properties are found that the effect of particle-particle and particle-wall interaction increases with the increase in particle volume fraction, external magnetic field, or the increase in tube length. Numerical flow results of the present analysis reveal that when the tube diameter decreases, the volume fraction increases, or the magnetic field strength increases, the velocity and pressure fields tend to be fully developed. Also, the pressure drop tends to increase, but the flow drag tends to be fixed.

並列關鍵字

magnetic nanofluids ； microfluidics ； Poiseuille flow ； finite difference

參考文獻

高源鍇, 2011, 奈米流體在漸縮管道內壓力與重力驅動流, 碩士論文, 機械工程學系, 中原大學.

張君輿, 2012, 磁性奈米流體懸滴界面性質之研究, 碩士論文, 機械工程學系, 中原大學.

Brinkmann, H., 1952, “The viscosity of concentrated suspensions and solutions,” J. Chem. Phys., 20, 571.

Brenner, H., 1970, “Pressure drop due to the motion of neutrally buoyant particles in duct flows,” J. Fluid Mech., 43, 641.

Chen, C. K. and Weng, H. C., 2005, “Natural convection in a vertical microchannel,” J. Heat Transf.-Trans. ASME, 127, 1053–1056.