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Abstract
An analytical model, for determining local and average condensation heat transfer coefficient in a horizontal two-phase, two-component, annular flow, was developed. Computations were carried out for the case of condensation of refrigerants R 12 and R 22 with and without small amounts of mineral oil. The theoretical parameters covered the range of 0% to 10% oil by mass, vapor quality range from 0.1 to 0.9, condensation temperature from 0 C to 40 C, & mass flux range from 100 to 700 kg/m2 s.
The analysis is based on solving the momentum and energy equations in the liquid film, which is determined by Reynolds analogy between turbulent heat and momentum transfer. To include the effect of the two-component nature of the flow, mixture average properties values were computed, assuming ideal mixing occurrence in the liquid phase.
The results demonstrated that increasing the oil ratio reduces the local and average condensation heat transfer coefficient than the corresponding values for oil free refrigerant. The effect of oil ratio, at low condensation temperature range from 0 C to 20 C, on the average heat transfer coefficient of R22 must be taken into consideration.