基于毛细管导波的微量液体粘度检测新方法  

A new method for the viscosity detection of micro liquids based on capillary guided waves

作　　者：吕福在 杨尔宇 伍建军[3] 唐志峰[4] Lyu Fuzai;Yang Eryu;Wu Jianjun;Tang Zhifeng(College of Mechanical Engineering,Zhejiang University,Hangzhou 310027,China;Huzhou Research Institute,Zhejiang University,Huzhou 313000,China;College of Biomedical Engineering and Instrument Science,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学机械工程学院,杭州310027 [2]浙江大学工程师学院,杭州310027 [3]浙江大学湖州研究院,湖州313000 [4]浙江大学生物医学工程与仪器科学学院,杭州310027

出　　处：《仪器仪表学报》2024年第6期219-230,共12页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(12474469)项目资助。

摘　　要：通过建立毛细管导波衰减率与波导内充液体粘度的基本关系可实现微量液体粘度快速测量,这对于样本量稀缺的工业及医学检测场景具有显著意义。然而,为实现微升级样本测量需要将管道尺寸缩减到毛细管级(外径2 mm及以下),但传统导波激励方法难以在毛细管上实现非接触式换能器装配以及纯净导波激励。本文基于磁致伸缩换能原理开发了一种适用于微量液体粘度检测的毛细管纵向导波检测传感器,成功地在外径为1.4 mm,壁厚0.1 mm的毛细管上激励纯净L(0,1)模态导波,单次测量所需样本量仅为113μL且重复性良好。通过仿真和实验探究包括永磁体与毛细管间距、毛细管壁厚和激励频率等测量相关影响因素的基础上证明了该设计的可行性和实用性。研究结果表明:收发两端永磁体与毛细管最优间距不同,当激励端永磁体与毛细管间距为10 mm,接收端永磁体与毛细管间距为7 mm时的接收信号幅值最优;在低频散范围内(500 kHz以下),检测分辨率总是随着频率的提高而增加;此外,毛细管壁厚的减薄也可提高粘度检测分辨率。最后,对比毛细管导波法与锥板法测量标准粘度液的实验结果,误差范围不大于3.04%,验证了毛细管导波法可对微量液体粘度实现准确测量。The viscosity of micro liquid can be quickly measured based on the construction of the fundamental relationship between the capillary guided wave attenuation rate and the liquid viscosity within the waveguide.It is significant for industrial and medical testing scenarios in which the sample is scarce.However,it is necessary to reduce the pipe size to the capillary level(the outer diameter is 2 mm or less)to achieve micro-upgrade sample measurement.Traditional guided wave excitation methods face challenges in achieving non-contact transducer assembly and pure guided wave excitation in capillaries.In this paper,a capillary longitudinal guided wave detection sensor suitable for the viscosity detection of trace liquid is developed based on the principle of magnetostriction.Pure L(0,1)modal waveguide are successfully excited on a capillary with an outer diameter of 1.4 mm and a wall thickness of 0.1 mm.The sample volume is only 113μL is required for a single measurement,with good repeatability.The feasibility and practicality of the design are proved on the basis of simulation and experimental exploration of the relevant influencing factors including the distance between the permanent magnet and capillary,capillary wall thickness and excitation frequencies.The results show that the optimal distances between the permanent magnets and capillaries differ at the transmitting and receiving ends,which are 10 mm and 7 mm respectively for the maximum signal amplitude.In the frequency range with low dispersion(below 500 kHz),the detection sensitivity always increases with the frequency.In addition,reducing the wall thickness thinning of capillaries can also improve the viscosity detection sensitivity.Finally,a comparison of the capillary guided wave method with the cone-plate method for measuring standard viscosity liquids showed an error range of no more than 3.04%,which verifies that the microfine tube guided wave method can achieve high-precision measurement of the viscosity of micro-volume liquid.

关 键 词：超声导波 磁致伸缩 液体粘度检测 毛细管 

分 类 号：TH703[机械工程—仪器科学与技术]