Study On Dynamic Characteristics Of Droplet Spreading Based On Millimeter Cantilever

The phenomenon of droplets spreading on solid surface exists in production and life widely.Different application scenarios have different requirements for the dynamic characteristics of liquid drops spreading.Therefore,it is of great significance to carry out quantitative analysis and experimental study on the dynamic characteristics of droplet spreading from the perspective of mechanics.According to the advantages and disadvantages of the existing research methods of droplets spreading dynamics at home and abroad,a new measurement method to study the dynamic characteristics of droplets spreading was proposed in this paper,which was based on the combination of the electrical measuring method and the mechanical measurement method with a millimeter cantilever.The dynamic characteristics of droplets spreading were studied experimentally,and the relationship between the force and the volume and viscosity of droplet was explored.The main research work of this paper is as follows:1.The existing experimental research methods of droplet spreading dynamic characteristics at home and abroad were summarized.With reference to the deficiencies of the existing research methods,a new method of measuring the dynamic characteristics of droplets spreading was proposed,which was based on the combination of the optical lever method and the electrical measurement method,with a millimeter cantilever as force sensor.2.The dynamic characteristics of droplets spreading process were analyzed theoretically.The changes of contact radius and radial force with time in the spreading processes of droplets were studied,as well as the three stages in the process of droplets spreading:viscous-inertial regime,inertial regime and viscous regime.The factors affecting the dynamic characteristics of droplets spreading(the radius and physical characteristics of droplets)were analyzed.XFlow software was used to simulate the spreading processes of droplets,and the relationship between the contact radius and viscosity of droplet was analyzed.3.A measuring system to study the dynamic characteristics of droplets spreading based on millimeter cantilever and RC circuit was designed.The measurement method of dynamic characteristics of droplets spreading was designed by combining the principle of optical lever method and the electrical measurement method.Based on the principle of electrical reproduction of micro-nano force value,the calibration scheme of the Force Sensitivity of the Optical Lever S_OL was designed,with an electrostatic force as standard load.Based on the above principles,the device measuring the dynamic characteristics of droplets spreading and the device calibrating the Force Sensitivity of the Optical Lever S_OL were set up,and the calibration experiment was carried out.The calibration result of S_OL was 8.847?N/V.4.Based on the built measuring device,the dynamic characteristics in the spreading processes of droplets were studied experimentally,and the variation of vertical force with time in the processes was measured.The dynamic characteristics of droplets spreading with different volumes and viscosities were measured,and the effects of droplet volume and viscosity on the dynamic characteristics of droplets spreading were studied.Through repeated experiments,the maximum relative standard deviation of the experimental results was 0.835%.The uncertainty of the measurement results was analyzed,and the relative composite standard uncertainty of dynamic force measurement was 1.684%.