The Key Technology Research Of Liquid Drop Analyzer

Fiber-capacitive drop analyzer(FCDA)can recognize and analyze liquid by monitoring the droplet growth.It merges the fiber sensor signals and capacitance sensor signals.A liquid has its certain liquid drop fingerprint(LDF)with same experimental environment.Thus,LDF can be used to identify the liquids and test their physical properties.With years of development,the performance and applications of FCDA have improved very well.However,there are still some hot study fields need to be explored,such as how to improve the instrument’s integration,stability and accuracy,and developing new data processing and analysis methods to extend the application range of FCDA.In this paper,the FCDA is systematically improved for this purpose.The main work of this paper is as follows:1.Design of the core device mechanical structure,making the system more stable,and conducive to the expansion of the realization of the function.Design the frame structure of the portable droplet analyzer instrument to explore the integrated structure distribution;2.The main circuit board is designed with DSP processor as the core,which can lay the foundation for the embedded instrument and increase the function of signal gain and temperature and humidity in the circuit.What’s more,it enhances the hardware filtering ability and anti-interference ability of the capacitance-to-digital converter chip;3.Strengthen the Labview monitoring window adaptability,increase the data save function,read function,and send commands to the computer function;4.The effective LDFs can be extracted by using Matlab in which added the function of automatic error correction and automatic compensation,which improve the accuracy effectively;5.The droplet formation of different liquids was simulated by Comsol software,and the electromagnetic field of the droplet in the capacitive sensor was simulated by Comsol software,from which we can find the physical meaning behind the FCDA;6.The discrimination and quantitative analysis of methanol solution,ethanol solution,propanol solution and Na Cl solution in different concentrations were carried out by using double linear discriminant analysis and principal component analysis.The correct identification of 8 groups of solutions different from the training samples was realized.The relative error of quantification is not more than 4.08%;7.The refractive index model of the liquid droplet with the surface tension correction is proposed.Compared with the simple linear model,it can be better applied to the refractive index estimation of alcohol solution with different surface tension of water.