A flow pattern independent drift flux model based void fraction correlation for a wide range of gas-liquid two phase flow

The main objective of this study is to present new equations for a flow pattern independent drift flux model based void fraction correlation applicable to gas-liquid two phase flow covering a wide range of fluid combinations and pipe diameters. Two separate sets of equations are proposed for drift flux model parameters namely, the distribution parameter (C-o) and the drift velocity (U-gm). These equations for C-o and U-gm, are defined as a function of several two phase flow variables and are shown to be in agreement with the two phase flow physics. The underlying data base used for the performance verification of the proposed correlation consists of experimentally measured 8255 data points collected from more than 60 sources that consists of air-water, argon-water, natural gas-water, air-kerosene, air-glycerin, argon-acetone, argon-ethanol, argon-alcohol, refrigerants (R11, R12, R22, R134a, R114, R410A, R290 and R1234yf), steam-water and air-oil fluid combinations. It is shown that the proposed correlation successfully predicts the void fraction with desired accuracy for hydraulic pipe diameters in a range of 0.5-305 mm (circular, annular and rectangular pipe geometries), pipe orientations in a range of -90 degrees <= 0 <= 90 degrees, liquid viscosity in a range of 0.0001-0.6 Pa-s, system pressure in a range of 0.1-18.1 MPa and two phase Reynolds number in a range of 10 to 5 x 10(6). Moreover, the accuracy of the proposed correlation is also compared with some of the existing top performing correlations based on drift flux and separated flow models. Based on this comparison, it is found that the proposed correlation consistently gives better performance over the entire range of the void fraction (0 < alpha < 1) and is recommended to predict void fraction without any reference to flow regime maps. (C) 2013 Elsevier Ltd. All rights reserved.