IMPROVED CORRELATION FOR DISPERSED FLOW FILM BOILING HEAT TRANSFER IN VERTICAL TUBES
An improved version of the author's general correlation for heat transfer during film boiling in tubes is presented. It is based on the two-step model. It has been verified with data for nine fluids flowing up in vertical tubes. The fluids include refrigerants, chemicals, cryogens, and water. The range of data included diameters from 1.09 to 24.7 mm, reduced pressures from 0.0046 to 0.97, flow rates from 3.7 to 5176 kg m-2s-1, and qualities from 0.1 to 2.4. The 834 data points from 31 sources are predicted with mean absolute deviation of 18.5 % giving equal weight to each data point and 16.1 % giving equal weight to each data set. Several other correlations are also compared to the same data and found to have much larger deviations.