Development Of Surface Light Scattering Apparatus For Liquid Viscosity And Surface Tension Measurement And Its Applications

Viscosity and surface tension are very important thermophysical properties which influence the selection of working fluids,design of efficient and energy-saving equipment and optimization of process.The work of thesis is to develop a surface laser light scattering apparatus which allows accurately measuring the viscosity and surface tension simultaneously.The software for data evaluations in the condition of low and high viscosity fluids was also developed.Compared with other viscosity and surface tension measurement method,the system has the equilibrium state,absolute measurement and non-contact measurement.Surface tension what is an important parameter of fluid interface properties affects the surface heat transfer,mass transfer and interface chemical reaction.However,the data obtained from the experimental is limited,and the workload is so huge especially for the mixture.Hence,the calculation method of surface tension is an important research content.This paper presents a new type of surface tension formula based on the contrast state principle so as to provide certain help for the engineering application and theory research of surface tension.The main achievements in this thesis are listed as follows:1.The light scattering theory model is set up,and get the corresponding solving the dispersion equation.Adopted optical mixing technology and photon correlation techniques established the bridge of surface wave theory and light scattering.We analyzed the heterodyne detection and the time correlation equation under the condition of scattered light power spectrum.This chapter also analyzes the spatial coherent solid Angle and the scattering volume and light scattering detection and some important factors.We determine the solving method of wave number in the dispersion equation.2.A new surface laser light scattering apparatus was developed which can be used for the measurement of surface tension and viscosity under saturated condition.The temperature can be well controlled within ±7 mk/2h in the temperature.The software was developed in Microsoft C++ platform to solve the dipersion equations.Four reference fluids: toluene,heptane were used to test the accuracy and reliability of new apparatus.Based on the uncetainty ananlysis,the uncertainties?k=2?of new developed apparatus for the measurement of surface tension and viscosity are 1% and 2%.3.On the basis of pendent drop apparatus system,the surface tension values of Methyl Laurate,Methyl pentanoate and methyl butyrate in the temperature range from 303.15³63.15 K.To fill the blank of the experimental data of the oxygen containing fuel and the alkane,to facilitate the design and application of the project.4.A generalized corresponging-states model based on two reference fluids was developed for the prediction of surface tension for pure fluids and the binary mixtures.Four parameters,pc,Tc,Vc and ? were used in this model.This model was tested on surface tension data of 30 pure fluids and 12 binanry mixtures.The average absolute deviation are 0.175 mN×m^-1.