Idea is to select one of the 5 above pre-defined forms (rectangular, cylindrical, spherical, truncated cone, spherical segment) and enter the confinement dimensions in which the high energetic material is embedded. For the present time, the software is restricted to simple geometries. We will provide the users with the possibility to simulate more complex geometries in a near future. The material characteristics (density, heat capacity and thermal conductivity) can be specified for each confinement layer.

Simulation of the heat transfer trough a multilayer confinement can be reduced to the analysis of a single layer and can then be extended from layer to layer (see Fig. 2.3). Thermal energy can be transferred into a bounded region by conduction, convection, or radiation. For some systems, the mathematical problem can be reduced to the conduction of heat, to which the discussion will be largely confined, but the other modes may occur at the boundaries.
 

Fig.2.3: Scheme of the multilayer confinement.
The simulation of the whole multilayer confinement reduces to the analysis of a single layer and can then be extended from layer to layer.

Considering one layer inside the confinement and simple geometries, it can be demonstrated that the mass of the layer which is taken for calculation of the heat transfer can be treated as an ‘infinite’ surface of thickness ‘d’ if the size o>f the pre-defined forms is large enough (i.e. ‘infinite’ in two directions and of wall thickness ‘d’ in the third, see eqs. 3.8, 3.9). It can be assumed that the heat transfer obeys Fourrier’s law (rate of heat transfer is proportional to the temperature gradient) and that the heat transfer in the y and z direction is negligible as compared to x direction. The presented model enables calculations of the temperature gradients using finite element methods, considering the heat transfer progress in the multi-layers. Different techniques can be applied in order to evaluate the thermal conductivity coefficients of the different layers. The equations have been developed using coordinates (x and t) where the whole surface of cavity will be derived from the different pre-defined geometries.