Design studies of rocket engine cooling structures for fatigue experiments

The fatigue life of a regeneratively cooled rocket engine is strongly controlled by the aerothermodynamic cyclic load of the combustion chamber structure. Experiments on a subscale rectangular rocket combustion chamber operated with gaseous methane (GCH4) are designed in order to investigate the structural response of the combustion chamber and the failure phenomena. Several design studies of the cooling channel structure of a replaceable fatigue specimen are presented, first based on one-cycle computations, later based on the computation of 20 cycles. One important aim of the work is to identify appropriate cooling channel structures and boundary conditions such that failure occurs after a relatively small number of cycles and in the centre cooling channels. The idea is to use the designed experiments for the validation of damage models in combination with fluid-structure interaction analysis.