An in-situ method of identifying ingredients of zeotropic refrigerants by inversion problem technique

ABSTRACT

An inversion method is applied to identify ingredients of zeotropic refrigerants in a circular duct. In the case of low Reynolds number and constant fluid pressure, the temperature distribution of direct heat transfer problem can be solved numerically. The thermophysical parameters of zeotropic refrigerants are determined by using inversion problem technique, the ingredients of refrigerants can be identified eventually. An in-situ experimental apparatus was proposed and three test samples with different composition refrigerants were conducted in this study. The experiment results show that the relative error of ingredients identification can be limited within 8.33%.

KEYWORDS:

• Zeotropic refrigerant
• thermophysical parameters
• ingredient identification
• circulation composition
• inversion problem technique

Nomenclature

$a$	=	Thermal diffusivity, $m^2/s$
C	=	volumetric heat capacity, $m^2/s$)
$C_p$	=	Heat capacity at constant pressure, $C_p$)
$J$	=	Jacobian matrix of the parameters, dimensionless
K	=	Consistency coefficient, dimensionless
$L$	=	The heating length, $m$
$P$	=	Certain coefficients for the thermal properties, dimensionless
$Pr$	=	Prandtl number, dimensionless
$p$	=	Pressure, Pa
$R$	=	The inner radius of the heat transfer pipe, $m$
$Re$	=	Reynolds number, dimensionless
$r$	=	Radial distance, m
$S$	=	L-M method error, dimensionless
$T$	=	Temperature, $\mathrm{K}$
$T_{\mathrm{b}}$	=	The initial temperature of the mixture
$T_w$	=	Outside wall temperature, $\mathrm{K}$
$U$	=	The parameter of the viscosity coefficient, dimensionless
$u$	=	The axial velocity, m/s
V	=	The molar volume
Greek letters	=
$\alpha$	=	The coefficient of heat conductivity
$\beta$	=	The coefficient of the heat capacity
$\lambda$	=	Coefficient of the heat conductivity, $\mathrm{W}/\left(\mathrm{m}\cdot \mathrm{K}\right)$
$\rho$	=	Density, kg/m3
$\varphi$	=	The volume fraction of composition
Superscripts	=
k	=	Algorithm step

Acknowledgments

This work was supported by National Natural Science Foundation of China (51679225); Natural Science Foundation of Shandong Province (ZR2017A0203); Special Fund for Agro-scientific Research in the Public Interest (201503135-04)

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51679225];Key Basic Research of Shandong Provincial Natural Science Foundation [ZR2017ZA0203];Special Fund for Agro-scientific Research in the Public Interest [201503135-04];