Reliable, Rapid and Cost Effective Fabrication Techniques for Larger Scale Scramjet Engines

TECHNOLOGY AREA(S): Air Platform OBJECTIVE: Develop a reliable, rapid, low risk, cost-effective method, technique or approach (additive manufacturing / welding / machining, etc.) for fabrication of large-scale, liquid-cooled structures applicable to high-speed air-breathing propulsion systems. DESCRIPTION: The Air Force Research Laboratory (AFRL) has been engaged in fundamental and advanced research and development of hypersonic technologies for hydrocarbon supersonic combustion ramjet (scramjet) engines. AFRL has continued to develop the technologies for larger scale engines for missile and platform vehicles. These larger-scale engines are expected to have intricate designs with intrusive devices that allow fueling of the entire large diameter combustor. Civilian application of these devices include high temperature heat exchangers and other liquid cooled structures. Thus far, the fabrication of such engines has proven to be slow, prohibitively expensive, not repeatable, and unreliable with a high risk of part rejection, especially structures with relatively small passages for cooling and fueling. The government seeks suitable techniques of fabrication that would ensure the elimination of clogging of passages during fabrication and reduce the unacceptable high part rejection rate. Reducing the weight of the heat exchanger and the time to manufacture are also factors to be considered. Smooth fluid passages are highly desirable to keep the heat transfer coefficient high and the fluid pressure drop low. Keeping the cost of fabrication low is always desired. In order to successfully perform the work described in this topic area, offerors may request to utilize unique facilities / equipment in the possession of the US Government located at Wright Patterson Air Force Base during the Phase-I and II efforts. Accordingly, the following items of Base Support may be provided: facilities in research cells 18, 19, or 22. Hardware set-up and actual testing will be performed by government personnel. Offeror may attend on site simply for supervision and support. PHASE I: Fabricate coupons of various materials and welds and a 5 x15 water-cooled panel with passages appropriately sized to handle temperatures (~3500F) and pressures (100psia) encountered in scramjet engine combustors and heat exchangers. Panel design will be coordinated and approved by AFRL. The panel will be submitted to AFRL for evaluation by testing in hypersonic test facilities located at Wright Patterson Air Force Base. Offeror will perform post-test analysis and report results. PHASE II: Improve, optimize and demonstrate the technique by fabricating a water-cooled 1X scale round scramjet combustor, to include the injection powerhead section with either struts or center body. Combustor design features/drawings to be coordinated and approved by the government. The fabrication technique will be validated by subjecting the hardware to testing in a relevant environment of temperature and pressure, i.e., at AFRL/RQH test facilities. Testing to be performed by the government. The hardware should also have the capability to be tested in contractor/university facilities. Offeror to perform post-test analysis and report all findings and results. PHASE III: Implement technique for fabricating leak tight complicated designs for large structures subjected to extreme temperatures/pressures. Improved design and manufacturing of hypersonic structures is of high interest to the government. No known repeatable, quick, low cost and reliable manufacturing technique is currently available. REFERENCES: 1. Edward T. Curran, "Scramjet Engines: The First Forty Years", Journal of Propulsion and Power, Vol. 17, No. 6 (2001), pp. 1138-1148.; 2. J. Philip Drummond, Marc Bouchez and Charles R. McClinton, "Overview of NATO Background on Scramjet Technology", Chapter 1, (2006).KEYWORDS: Hypersonic Structures, High Temperature Materials, Hydrocarbon Scramjet Manufacturing, Fuel & Water Cooled Passages, Joining Of Dissimilar Materials, Additive Manufacturing, Welding Techniques