Condensation Heat Transfer of R32 and R454B Inside a Microfin Tube as an Alternative Refrigerant to R410A

Experimental and Theoretical Study on Condensation Heat Transfer of Nonazeotropic Refrigerant Mixtures R1234yf/R32 Inside a Horizontal Smooth Tube

The condensation heat transfer characteristics of nonazeotropic mixtures R1234yf and R32 (mass fractions of 0.52:0.48 and 0.77:0.23, respectively) inside a horizontal smooth tube (inner diameter 4 mm) were experimentally studied at mass fluxes ranging from 100 to 300 kg/m s. A prediction model for the forced convective condensation heat transfer characteristics of nonazeotropic refrigerant mixt...

Numerical Investigation of Flow behavior and Heat Transfer Characteristics inside Herringbone Microfin Tube

A numerical investigation is carried out for single phase flow behavior and heat transfer characteristics inside herringbone microfin tube by using a commercial CFD code FLUENT. It solves the three-dimensional NavierStokes equations in strong conservation form. Turbulence closure is provided by the standard k- turbulent model with enhance wall treatment. Numerical results showed that herringbo...

Condensation Heat Transfer of Pure Refrigerants in Microfin Tubes

Enhancement Effect of a Microfin Tube in Condensation of R407C

In the present paper the heat exchange performance of a counter flow double-tube condenser for a ternary refrigerant mixture R407C, composed ofHFC32/HFC125/HFC134a, is calculated using a prediction method developed by the present authors. The axial distributions of vapor and liquid bulk mass fraction, temperature, heat flux, mass flux, etc., are obtained for both a smooth tube and a microfin tu...

Influence of Oil on Heat Transfer Characteristics of R410A Flow Boiling in Conventional and Small Size Microfin Tubes

In order to extend the existing heat transfer coefficient correlation of R410A-oil mixture flow boiling in conventional size (7.0 mm) microfin tube to be suitable for widely used small diameter tubes (4.0~5.0 mm), the experiments of R410A-oil mixture flow boiling inside three small diameter microfin tubes with different outside diameters of 4.0~5.0 mm and different microfin structures were perf...