K.2.2 COMOVA: COntamination MOdelling and Vent Analysis

COMOVA was developed by ONERA (physics) and HTS AG (interfaces) under ESA sponsorship. It is now distributed since the year 2002 by ONERA (see http://www-mip.onera.fr/comova).

It covers the physical modelling of the following sources:

• Outgassing: it follows the European physical approach of residence time (same model and database as OUTGASSING)

• Venting: vents can be modelled either similarly to an outgassing source (hence representative of the efflux from an outgassing cavity) or as commanded (then more representative of purging)

Molecular transport is especially sophisticated. It takes into account:

• Deposition and reemission (the latter being modelled through "reemission residence time")

• Reflections on surfaces

• Gas phase reflections (self and ambient scattering) with a BGK model using realistic densities for ambient and outgassed species

Pre and post processing for COMOVA are done in external tools with which COMOVA is interfaced (FEMAP and I-DEAS).

One hierarchy level of kinematics modelling, i.e. modelling of moving parts is also enabled, as the relative motion or pointing of sub models with respect to the main model along the orbit