A Method Of Identifying The Viscosity Coefficient And Ingredient Of Mixed Liquid Based On Temperature Field

The identifying for thermophysical parameters and ingredient of mixed liquid not only is a difficulty on theory but also on project. Especially for non-azeotropic refrigerant, it is much harder on identifying for its temperature-variation properties. There is an urgent need on thermophysical parameters and ingredient identifying. A method on identifying the ingredient of mixture based on the measured temperature field by inverse heat transfer problem is given in this paper.Efforts to identify the ingredient of mixed refrigerant mainly focused on the following two aspects:the thermophysical parameters can be estimated by inverse problem method and the correlativity of thermophysical properties between mixed refrigerant and ingredient should be given. In this paper, based on the measured temperatures, the viscosity coefficient of non-azeotropic refrigerant is determined by using Levenberg-Marquardt method. And according to the experienced or semi-empirical correlation formulas and the information about viscosity coefficient the ingredient of refrigerant can be identified. In addition, some new correlation formulas were given out for the mixed liquid used in this paper. An in-situ experimental apparatus was set up and R407c with difference composition of R32, R125 and R134a as the testing fluid was taken into consideration in this study. The results show that the error of identifying the ingredient of non-azeotropic refrigerant is within 5.56% by inverse heat transfer problem (IHTP).A method to identifying the thermophysical parameters by measuring the pipe convection heat transfer temperature field was presented in this paper. An improved mixing length turbulence model was developed by introducing the effect of density fluctuations into the equations of turbulent transport, which can be applied to calculate the temperature field and velocity field inside the pipe. Using Levenberg-Marquardt method got the viscosity coefficient in the control equations by measured temperature field. The result showed that IHTP is feasible for identifying the thermophysical parameters.An in-site method to identify the ingredient of mixed liquid based on the measured temperature field by using Levenberg-Marquardt method and the experienced or semi-empirical correlation formulas between viscosity coefficient and ingredient was given out which can be widely used in industry.