AIR-SIDE HEAT TRANSFER AND PRESSURE DROP IN SPIRAL WIRE-ON-TUBE CONDENSERS

The air-side thermal-hydraulic performance of spiral wire-on-tube condensers is investigated experimentally in this paper. Sixteen prototypes were manufactured and tested in an open-loop wind tunnel calorimeter. The influence of the following geometrical parameters was evaluated: the number of tube passes, the radial and longitudinal tube spacings and the wire spacing. Measurements of the air-side thermal conductance and pressure drop were carried out for air flow rates ranging from 70 to 220 m(3)/h. The data were correlated using empirical relationships for the Colburn j-factor and the Darcy friction factor. The agreement with the experimental data presented absolute average deviations of 2.8% for the heat transfer rate and 4.8% for the pressure drop. A quantitative analysis is presented to provide the most viable configuration from the point of view of its application in a domestic refrigerator.