The accuracy of numerical simulations for the prediction of cavitation in cryogenic fluids is of critical importance for the efficient design and performance of turbopumps in rocket propulsion systems. One of the main remaining challenges is efficiency in modeling of the physics, handling the multi-scale properties involved and developing robust numerical methodologies. Such flows involve thermodynamic phase transitions and cavitation bubbles that are on a smaller scale than the global flow structure. Cryogenic fluids are thermo-sensitive, and therefore, thermaleffects and strong variations in fluid properties can alter the cavitation properties. The aim of this work is to address the challenge posed by thermaleffects. The Rayleigh–Plesset equation is modified by the addition of a term for convectiveheattransfer at the interface between the liquid and the bubble coupled with a bubbly flow model to assess the prediction of thermaleffects. We perform a parametric study by considering several values of and models for the convectiveheattransfer coefficient, hb, and we compare the resulting temperature and pressure profiles with the experimental data. Finally, the results of a 2D simulation with a commercial CFD code are presented and compared with the previous results. We note the importance of the choice of hb for the correct prediction of the temperature drop in the cavitating region, and we assess the most efficient models, underlining that the choice of hbestimation model in a cryogeniccavitatingflow is more important in the bubble growth phase than in the bubble collapse phase.
Influence of convective heat transfer modeling on the estimation of thermal effects in cryogenic cavitating flows
DE GIORGI, Maria Grazia;FICARELLA, Antonio
2012-01-01
Abstract
The accuracy of numerical simulations for the prediction of cavitation in cryogenic fluids is of critical importance for the efficient design and performance of turbopumps in rocket propulsion systems. One of the main remaining challenges is efficiency in modeling of the physics, handling the multi-scale properties involved and developing robust numerical methodologies. Such flows involve thermodynamic phase transitions and cavitation bubbles that are on a smaller scale than the global flow structure. Cryogenic fluids are thermo-sensitive, and therefore, thermaleffects and strong variations in fluid properties can alter the cavitation properties. The aim of this work is to address the challenge posed by thermaleffects. The Rayleigh–Plesset equation is modified by the addition of a term for convectiveheattransfer at the interface between the liquid and the bubble coupled with a bubbly flow model to assess the prediction of thermaleffects. We perform a parametric study by considering several values of and models for the convectiveheattransfer coefficient, hb, and we compare the resulting temperature and pressure profiles with the experimental data. Finally, the results of a 2D simulation with a commercial CFD code are presented and compared with the previous results. We note the importance of the choice of hb for the correct prediction of the temperature drop in the cavitating region, and we assess the most efficient models, underlining that the choice of hbestimation model in a cryogeniccavitatingflow is more important in the bubble growth phase than in the bubble collapse phase.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
