Improved correlation for heat transfer during condensation in inclined tubes

Condensers with inclined tubes (i.e. inclinations other than horizontal and vertically downwards) are used in many applications. Hence accurate prediction of heat transfer in inclined tubes is needed. The author had earlier published a correlation which was in good agreement with the limited data available then. Data from many more experimental studies has become available now. A new correlation has been developed considering all available data which gives better quantitative and qualitative agreement than the author's earlier correlation. The data correlated includes 10 fluids (water, halocarbon refrigerants, and chemicals), tube diameters 0.5 mm to 40 mm, orientation - 90 degrees to +90 degrees, reduced pressures 0.0046 to 0.886, mass flux 1 to 1360 kg m- 2 s- 1, and qualities 0.1 to 0,96. The data are from 15 studies. The 1645 data points are predicted with mean absolute deviation of 17.7%. The development of the new correlation is described and detailed comparison of data with the correlation is presented.