梯度润湿铜沟槽中的流体流动与液滴移动

发布时间：2018-02-02 21:54

本文关键词： 梯度润湿表面开放式沟槽液滴铺展微流体上升液滴移动　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：(1)采用置换法在铜基开放式沟槽及平面制备接触角连续变化的梯度润湿表面,梯度范围为89.1°-23.6°。根据氧化还原反应原理,以硝酸银作氧化剂,金属铜置换银离子沉积在铜基表面。为控制反应速率,向硝酸银溶液加入氨水形成银氨络离子。研究液滴在具有相同梯度范围内沟槽及平面上的铺展现象。结果表明:在相同的梯度范围内,液滴在沟槽内的铺展平均速度及铺展距离均超过平面上的铺展平均速度及铺展距离。通过扫描电镜(SEM)和X-射线衍射仪(XRD)分析表面形貌结构和表面化学组成对液滴铺展现象的影响。(2)采用碱辅助氧化法改变开放式铜基微沟槽内壁的润湿性,分别建立梯度润湿表面(梯度范围90.2°-5.4°)和单一润湿表面(接触角分别为20.2°和5.4°)。研究梯度力对微流体毛细上升运动的影响。采用工业高速摄像机记录微流体的上升过程。结果表明:微沟槽的直径越小,微流体的上升高度越高,上升平均速度越快;微沟槽壁面的润湿接触角越小,微流体受到的毛细力越大;微流体在梯度微沟槽内的上升高度高于单一接触角微沟槽内的上升高度;微流体在梯度润湿微沟槽内的上升平均速度明显快于单一接触角微沟槽内的上升平均速度。通过扫描电镜(SEM)和X-射线衍射仪(XRD)分析了表面形貌结构和表面化学组成的变化是梯度力产生的根本原因。(3)采用电化学沉积法建立142.1°-90.2°接触角连续变化的梯度润湿表面,以无水硫酸铜和浓硫酸混合溶液作电解液,石墨电极作阳极,带有环形开放式沟槽的铜板作阴极。研究体积为8μl、5μl和3μl的液滴在梯度润湿铜基沟槽及平面的移动现象,分析不同润湿表面上的液滴滚动角。结果表明:在梯度力的驱动下,液滴可以在倾斜表面(倾斜角10°)上作爬坡运动;在相同梯度范围内,液滴在沟槽内的移动平均速度比平面上的移动平均速度快,且移动距离比平面上的移动距离长。通过扫描电镜(SEM)和X-射线衍射仪(XRD)分析表面形貌结构和表面化学组成对液滴移动现象的影响。
[Abstract]:The gradient wetting surface with continuously changing contact angle was prepared by displacement method in open trench and plane of copper base. The gradient range was 89.1 掳-23.6 掳. According to the principle of redox reaction. Silver nitrate was used as oxidant and copper ion was deposited on the surface of copper base. The reaction rate was controlled. Silver ammonia complex ions were formed by adding ammonia to silver nitrate solution. The spreading phenomenon of droplets in grooves and planes with the same gradient was studied. The results show that the droplets are in the same gradient range. The average spreading velocity and spreading distance of droplets in the grooves are higher than the average spreading velocities and spreading distances on the plane. SEM (scanning electron microscopy) and XRD (X ray diffractometer). The effect of surface morphology and chemical composition on droplet spreading was analyzed. (2) the wettability of open copper based microgroove inner wall was changed by alkali assisted oxidation. Gradient wetting surfaces (gradient range 90.2 掳-5.4 掳) and single wetting surfaces (contact angles 20.2 掳and 5.4 掳) were established respectively. The effect of gradient force on the rising motion of microfluid capillary is studied. The rising process of microfluid is recorded by industrial high-speed camera. The results show that the diameter of microgroove is smaller. The higher the rising height of the microfluid, the faster the average rising speed. The smaller the wetting contact angle of the microgroove wall is, the greater the capillary force of the microfluid is. The rising height of microfluids in gradient microgrooves is higher than that in single-contact microgrooves. The rising average velocity of microfluids in gradient wetting microgrooves is obviously faster than that in single contact angle microgrooves. It is analyzed that the change of surface morphology and chemical composition is the root cause of gradient force. The gradient wetting surface with continuous change of contact angle 142.1 掳-90.2 掳was established by electrochemical deposition. With anhydrous copper sulfate and concentrated sulfuric acid as electrolyte, graphite electrode as anode and copper plate with annular open groove as cathode, the volume of study is 8 渭 l. The moving phenomena of 5 渭 l and 3 渭 l droplets in gradient wetting copper base grooves and planes are analyzed. The rolling angles of droplets on different wetting surfaces are analyzed. The results show that the droplets are driven by gradient force. The droplets can move up the slope on the inclined surface (angle of inclination 10 掳); In the same gradient range, the moving average velocity of droplets in the grooves is faster than that in the plane. The moving distance is longer than that on the plane. The effect of surface morphology and chemical composition on droplet movement is analyzed by scanning electron microscopy (SEM) and X-ray diffractometer (XRD).
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.5

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