This Master's thesis covers the work conducted in order to investigate the possibilities to simulate a stationary and a rotating base-bleed unit with regards to combustion and using a solid propellant boundary condition in Computational Fluid Dynamics (CFD). Previous work on simulations with regards to drag coefficients when a base-bleed unit is used have been done. No work on simulating the inside behaviour of a base-bleed unit have however been done before. It is therefore of interest to investigate if such a model can be created. The purpose behind this work is to see if a working simulation model can be constructed and if data from this model can replace or complement data from static burn tests. Simulations should cover a combustion case covered from previous conducted work on simulating combustion of base-bleed gas. Both rotation of the base-bleed unit and initial temperature of the propellant should be possible to implement into the created simulation model. Data that is of interest is the pressure inside the unit, mass flow from the propellant and the effects of initial temperature of the propellant. If there was time changes in atmospheric pressure should be done in simulations. Simulations should be done in the CFD software iCFD++ provided by Metacomp Technologies. Work has been conducted doing studies on an existing base-bleed model that describes how mass flow from propellant relates to a pressure.

Mesh studies on previous cases on projectiles with the addition of base-bleed have been conducted in order to create a working mesh model for the base-bleed unit. After a working mesh was constructed work on how the existing base-bleed model could be implemented in iCFD++ with the use of a solid propellant boundary condition was done. When a successful implementation was done simulations with respect to rotation and change in propellant geometry was set up for different points in time of the burn cycle of the propellant. The effect of the initial temperature on the propellant could be done in simulations but temperature based data on the propellant could not be extracted from simulations. Pressure data could be extracted from the final simulation model but did not correspond well with real data. Despite questionable correspondence to real pressure data results showed that a simulation model can be constructed for a split propellant geometry but more work is needed in order to obtain a fully working model. Since only the effect of initial temperature on the propellant could be taken into account and burn tests on the propellant alone still needs to be performed a simulation model can not replace test data but it can be used to complement real data.