Toward the chill-down modeling of cryogenic upper-stage engines under microgravity conditions using the thermal-hydraulic code COMETE

G.-M. Moreau (1) , Kc. Le Thanh (1) , C-H. Bachelet (2) , D. Duri (2)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 SNECMA Vernon [Vernon]

The design of the Vinci re-ignitable upper stage cryogenic engine requires detailed analysis, modeling activities and experimental work in order to optimize the engine chilldown phase in a paramount effort to further increase the launcher payload. Prior to any Vinci starting sequence the oxidizer and fuel feeding lines and turbo-pumps must be properly preconditioned and cooled down. Moreover due to the Vinci re-ignition capability the chill-down phase has to be performed during the upper stage coast phases under microgravity conditions. As a high efficiency of the chill-down process is required to achieve the minimum consumption of propellants within the established duration and temperature criteria to fully understand the chill-down thermo-fluid dynamics and to reliably predict the heat transfer rates and temperature history of the propulsion system, Snecma developed the thermal-hydraulic code COMETE by coupling and adapting the unsteady thermal code Samcef-Thermal, developed by Siemens, and state-of-the-art thermal-hydraulic code CATHARE, developed by CEA. While the former simulates the thermal evolution of complex 3D parts such as the engine turbopumps and regenerative circuits of the Vinci engine, the CATHARE code is used to model the hydrogen and oxygen two-phase flows. In order to understand the critical microgravity chill-down phase, CATHARE and COMETE simulations of specially instrumented Ariane 5 commercial flights will be carried out. During such flights an additional chill-down is performed on the HM7B/ESC-A upper-stage after the separation of the payload and prior to the upper stage safety neutralization. The simulation results will be compared to the available telemetry data in order to validate the numerical tools and the modeling methodology.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

G.-M. Moreau, Kc. Le Thanh, C-H. Bachelet, D. Duri. Toward the chill-down modeling of cryogenic upper-stage engines under microgravity conditions using the thermal-hydraulic code COMETE. EUCASS 2015 - 6th European conference for aeronautics and space sciences, Jun 2015, Cracovie, Poland. ⟨cea-02500837⟩