Thermo- and Fluidmechanical Analysis of High Aspect Ratio Cooling Channels

This study compares the results of three-dimensional and one-dimensional thermal and fluid flow analysis methods, applied to electrically heated tube flow experiments and also to cooling passages of regeneratively cooled combustion chamber well structures. It will be shown, that both methods can be applied very well to the simple case of the tube flow, but the more complex geometry and the boundary conditions in the case of a regeneratively cooled combustion chamber wall structure brings along a great deviation between both methods. This lies in the fact that one dimensional analysis tools neglect thermal stratification. The solution of the Navier Stokes and the energy equation is necessary to include this effect, but this method is to computationally costly to the part of an optimization of regeneratively cooled wall structures. Therefore a new stratification approach based on the usage of empirical correlations for heat transfer and pressure loss is developed. On base of the results of the analysis an experiment is planned to validate the theoretical models

Thermal Analysis of Expander Engine Wall Structures

The upper stage of the European rocket Ariane V will be equiped with the cryogenic expander cycle engine VINCI. Liquid hydrogen (LH2) and liquid oxygen (LOX) are transported from the fuel tanks to the combustion chamber by means of turbopumps, which themselves are driven by an expansion of warm and highly compressed gasous hydrogen in the turbines. The necessary heat input into the hydrogen takes places in the regenerative cooled combustion chamber wall structure