Modeling postcritical two-phase heat transfer in EcosimPro/ESPSS environment

Flow boiling in cooling channels is a complex phenomenon due to the wide range of flow patterns that can emerge during coolant vaporization, resulting in various heat transfer regimes. To provide reliable yet efficient simulations for accurate estimation of coolant heat transfer capabilities in support of liquid rocket engine design, a new model for two-phase heat transfer has been implemented in the EcosimPro/European Space Propulsion System Simulation (ESPSS) tool. The accuracy of this model has been validated against experimental data for cryogenic fluids, focusing on wall temperature prediction and Critical Heat Flux (CHF) position. A comparison with the built-in model available in the EcosimPro software was also conducted. Results indicate that the built-in model can lead to significant inaccuracies in wall temperature predictions due to the lack of proper CHF modeling. Conversely, the new model shows substantial improvement in predictive capabilities, especially in cases where CHF occurs at the channel inlet.