(A) modified two-phase pressure drop correlation based on a comparative study of existing models and uncertainty analysis

Abstract

The two-phase pressure drop models and correlations in the literature have been examined for their applicability to Pressurized Water Reactor conditions. They were tested against 209 experimental steam-water pressure drop measurements under diabatic conditions. The data represented several geometries and had the following property ranges;\\ \begin{eqnarray*} & \mbox{Pressure} & 8.6-16.5\; MN/m^2\; (1250-2400\; \mbox{psia})\\ & \mbox{Mass}\;\; \mbox{velocity} & 406.8-8000\; kg/m^2-s\; (0.3-5.9\; Mlb/ft^2-hr)\\ & \mbox{Exit}\;\; \mbox{quality} & \mbox{subcooled}- 60\%\\ & \mbox{Equivalent}\;\; \mbox{diameters} & 4.83-38.10mm\; (0.19-1.5 in) \end{eqnarray*}\\ The models and correlations which were found to have best performance for above range of parameters were the (a) homogeneous model by Owens (1961), (b) Baroczy model (1968), and (c) Chisholm model (1972). The correlations were also evaluated with the available experimental data which were sub-divided into a number of set based on the properties and flow conditions. A new correlation has been developed in the present work by the application of correction factor to the total pressure drop term. The new correlation is tested for its accuracy by comparing with the existing experimental data and predictions of the existing correlations. The results of the comparison show that the agreement between the predictions of the new correlation and the experimental data is fairly good and the correlation seems to be superior to all other existing correlations examined for the operating conditions of PWERs.