CEDRIC: A Software for One and Two Phase Flow Applications 932131
The first part of this paper concerns the presentation of CEDRIC. CEDRIC (Code d'Etudes Dynamique de Réseaux Inter Connectés) is a one dimensional thermalhydraulic software which is capable of modelling single and two phase flow for steady state and transient conditions. It has been developed by CEA/TECHNICATOME (French national nuclear agency) for nuclear cooling system design and failure analysis. It is a “3+1” equations software (mass, momentum, energy for the fluid and energy for the walls linked to fluid). These equations are solved using a finite difference method with a fully implicit resolution, which allows the use of large time steps in comparison to the ones imposed by the Courant limit.
In order to fulfil the requirements of spaceborne fluid loop analysis, CNES required some adaptations such as new fluids and new elements (radiators for example). So, CEDRIC is today able to handle many space thermal hydraulic applications as the complete HERMES Active Thermal Control Subsystem or complex two phase loops.
The second part of this paper presents the CEDRIC theoretical qualification status for one and two phase flow applications (qualification of fluid properties, heat transfer correlations, pressure drop correlations, wave propagation velocities of enthalpy, mass flowrate and pressure).
Finally, in the third part, comparisons between CEDRIC and FHTS (the ESA standard thermalhydraulic software; PSS-03-105) are presented. These comparisons concern the modelisation of the one and two phase flow wave propagation velocities, the modelisation of a freon 114 loop with radiators, a modelisation of a water servicer and a comparison with experimental data, and at last, a modelisation of a mechanically pumped two phase loop (which is developed for two phase experiment for microgravity conditions).