深海探测电极腔液—液高效驱替机理  

Mechanism of High-performance Liquid-liquid Displacement for Deep-sea Sensor Chamber

作　　者：樊炜[1,2] 潘华辰[2] 陈鹰[1,2] 

机构地区：[1]浙江大学流体传动与控制国家重点试验室,杭州310027 [2]杭州电子科技大学机械电子工程研究所,杭州310032

出　　处：《机械工程学报》2010年第4期143-149,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金重点(40637037);国际重大科技合作(2004DFA04900)资助项目

摘　　要：为实现深海pH探测电极的在线自校正,按异重流原理设计一种三维结构的新型深海pH探测电极腔。在腔体内设置上、下两个出水口,利用重力分层实现探测电极腔内重液和轻液间的高效驱替:重液驱替轻液时,重液在重力作用下形成底部异重流,将轻液从上出水口压出;轻液驱替重液时,轻液在重力作用下形成上层异重流,使重液从下出水口排出。运用计算流体动力学方法分析深海pH探测电极腔内速度场和浓度场的分布规律,采用酸性葡萄酒和碱性缓冲液的驱替试验检测腔体的驱替性能,同时阐述发生液—液高效驱替的机理,分析pH探测电极腔的驱替性能与雷诺数、密度差的关系。仿真和试验结果都表明,在海水和缓冲液存在密度差的情况下,圆筒型(SS-Ι)pH探测电极腔不能实现完全驱替,而三棱柱型(SS-ΙΙ)pH探测电极腔可以获得好的驱替性能。A novel three-dimensional chamber of the deep-sea pH sensor is designed on the basis of gravity currents principle to facilitate online self-correction.The flows are driven by buoyancy differences between the interior and exterior fluids.A stable stratification and efficient displacement develop in this case.There are two water outlets in the chamber.Bottom gravity currents occur when the dense fluid enters through the inlet,displaces the light fluid in the chamber and pushes it out through high level outlet.On the other hand,surface gravity currents occur when the light fluid enters through the inlet,displaces the dense fluid in the chamber and pushes it out through low level outlet.Computationally,the distribution of velocity field and concentration field in the chambers is investigated with the computational fluid dynamics method.Experimentally the performances of the fluid displacement in the chambers are measured through the wine dye and the pH buffer solution displacement experiment and the effect of the Reynolds number and the Atwood number on the displacing efficiency is quantitatively investigated.Both computational and experimental results show that the barrel-shaped chamber of pH sensor（SS-Ι） cannot achieve full displacement,while the triangular prism chamber of pH sensor（SS-ΙΙ） can accomplish better liquid displacement as long as the sea water and buffer solution have different densities.

关 键 词：pH探测电极 标定 驱替 缓冲液 

分 类 号：TH766[机械工程—仪器科学与技术]