DOI: 10.1615/ICHMT.1981.AdvCourseHeatExch
ISBN Print: 978-0-07062-806-9
Two-Phase Pressure Drop for Condensation inside a Horizontal Tube
ABSTRACT
Experimental data for the pressure drop of a condensing flow in a horizontal tube have been compared with the predictions of an annular flow model. The comparisons are made using data obtained by the authors and using further data from several other sources. The data span a mass flux range of 20 to 1250 kg/m s and are for tube diameters ranging from 0.007 m to 0.025 m. The experimental data are for the condensation of steam, propanol, methanol, refrigerant 113, refrigerant 12, refrigerant 22 and n-pentane.
It is found that the general trends of the predictions of the annular flow model, when used in its no entrainment limit, are in good agreement with the experimental data. However, the frictional component of the local pressure gradient predicted by the model is found to be sensitive to the correlation employed to describe interfacial roughness. Of two such correlations tested, one tended to overpredlct and the other to underpredlct the frictional pressure gradient. It is concluded that an annular flow model has the potential for accurate prediction of pressure drop for condensing flow in a horizontal tube. Particular care, however, must be taken in the choice of interfacial roughness correlation.