The object of the following dissertation is the design of a prototype of an innovative heat exchanger (HE) for an aircraft engine cooling system made by Additive Manufacturing (SLM). The new shape design is referred to the inner core of the compact HE to enhance the convective heat transfer coefficient and reduce, at same time, the pressur drop occurred across the ducts of the block. The compact heat hexchanger is embedded in the engine, as part of the cooling system of the aircraft built by I.C.P. Aziazione srl. In fact this work is the summary of my Master Thesis that I have done in stage The stage started in september 2018 and ended in february 2019.