Additively Manufactured Scramjets

The Air Force requires large scale scramjet engines but current fabrication methods have long lead times, high part rejection rate, and great expense due to hand-rework by skilled fabricators. Physical Sciences Inc. (PSI) will address these shortcomings by continuing development of our Additive Manufacturing (AM) plus brazing process that allows duct segments and other components to be joined together into large-scale, highly complex scramjet assemblies. PSI’s method makes it possible to combine many pieces of potentially differing materials together into a leak-free whole. Different metals can be used, as can dissimilar materials such as ceramic and metal. This method makes use of PSI’s previously developed heat exchanger geometry, which has resulted in four times reductions to the weight of airborne heat exchangers. PSI’s method has demonstrated capability to contain over 27 MPa (4000 psi) of internal pressurization, a suitable proof pressure for the typical 1000 psi fuel pressure requirement. In the proposed Phase I program, PSI and STTR partner will build additional, representative scramjet test segments from several materials. We will braze them to show viability of the joining process, and assess the suitability of the assembly to overall scramjet fabrication. In Phase II, a scramjet duct segment will be produced.