Influence of Interphase Forces on Onset of Fully Developed Subcooled Flow Boiling at High Pressure

Abstract

Accurate prediction of the onset point of fully developed boiling (FDB) in subcooled flow boiling is crucial for the design of industrial equipment. In this work, Eulerian−Eulerian two fluid model incorporated with the Rensselaer Polytechnic Institute (RPI) wall boiling model was used to investigate high-pressure subcooled boiling flow, with particular attention to the model’s capability of objectively predicting the onset of FDB. After using the experimental data to verify the model, the present work covered a working range of P=6.81−15.5MPa, G=966−2123 kg/m2s, q=750−1500 kW/m2. Results show that the onset of FDB coincided with the inflection point on the axial distribution of boundary void fraction. Lift force had no obvious effect on axial distribution of mean void fraction but had a significant influence on radially local void fraction and determination of the onset of FDB. The turbulent dispersion force, wall lubrication force had a great influence on both axial and radial distribution of void fraction, directly affecting the onset of FDB. Performance of interphase force models in boiling flow was found to be different from that in adiabatic flow, and the underlying mechanism was further revealed. At last, the most feasible interphase force models for predicting onset of FDB were recommended.