The primary objective of the present project was to develop an optimal design concept of a hex for application in the IRA-engine with respect to efficiency, operational life, weight and cost. It was an intended goal to check whether these requirements can be attained, whether constraints or restrictions on the requirements may be necessary, and if so, what effects such constraints will have on the performance of the engine.


To achieve the goals, a complete design and construction process has been carried out which included also the thermal and structure-mechanical analyses for the purpose of attaining an estimated operational lifetime. Flow tests and CFD modelling have been performed in order to optimise the orientation of the various elements of the heat exchanger in the exhaust duct of the IRA-engine and to make realistic assessments of pressure losses. Furthermore, manufacturing investigations have been undertaken with the goal of reducing the high expenditure costs, but with a minimal influence on the performance and life of the heat exchanger.