Comparison of phase interaction models for high pressure subcooled boiling flow in long vertical tubes

In this article, Eulerian two fluid model is used for prediction of high pressure subcooled nucleate flow boiling in vertical tubes. Predictions of different turbulence models, phase interaction models have been compared with previous experimental data. Axial and radial profiles of vapor fraction and liquid temperature have been used for comparison of these models. Bubble departure diameter models and bubble induced turbulence models show the significant effect on the vapor fraction prediction. It was found that use of Kocamustafaogullari and Ishii models for bubble departure diameter and nucleation site density are suitable for predicting vapor distribution and liquid temperature for high pressure boiling. Models of interfacial heat transfer and bubble departure frequency developed for low pressure or atmospheric conditions showed a good applicability for high pressure conditions also. Inclusion of wall lubrication force showed the void fraction peak near the wall. Simulated pressure drop predictions for high pressure flow boiling in a 13 m long vertical tube shows the error of 2-10% with experimental data. This indicates that computational fluid dynamics (CFD) is the promising technique for pressure drop prediction.