Validation of the transient two-phase flow model MONA against dryout experiments

Static dryout experiments based on vertical tubes have been conducted at KTH (Becker et al., 1983; 1992). The experiment covers 3 different tube diameters, 10 mm, 15 mm and 25 mm, and 6 different axial power distributions. The loop pressure varies from 1 to 20 MPa and the mass and heat fluxes from 500 to 3000 kg/m2 and 90 to 3000 kW/m2, respectively. A subset of the available experimental data set from KTH has been used previously for the validation of the transient two-phase flow simulator MONA (Hoyer 1995a) against dryout and post-dryout heat transfer (Hoyer 1998). This paper compares an extended range of the KTH data to both empirical correlations and to the MONA model. The influence of axial heat flux distribution, pressure and mass and heat flux is discussed. The MONA model generally provides good results for dryout position and power, and successfully reproduces the influence of relevant parameters, especially the strong axial variation of the heat flux. (author)