Improved Materials and Designs for High Pressure Wind Tunnel Applications

ABSTRACT: This Phase I effort will identify and evaluate candidate materials to replace existing beryllium-copper alloy components for use in aerospace ground test flow facilities. The candidate materials must offer similar or better performance metrics (dimensional stability, lifetime, etc.), be domestically and readily available, offer similar or cheaper costs, and the ability to withstand temperatures and pressures on the order of 1000?F and 2000 psi, respectfully. This will be achieved through the identification of the wind tunnel nozzle details; selecting candidate materials based on the desirable melting temperature, mechanical erosion resistance, elevated temperature stability, thermodynamic stability, and theoretical thermal-structural performance; detailed design and analysis trade studies via the finite element method to establish preliminary design options; billets/test specimens fabrication; and characterization of critical material properties. The fabrication approaches will consider Vacuum Plasma Spray (VPS), electrochemical deposition (EL-Form?), and Hot Isostatic Pressing (HIP). The characterization efforts will measure critical properties including thermal diffusivity (thermal conductivity, density, and specific heat), thermal expansion, Young?s modulus, and tensile strength/strain capability at select temperatures within the range of 75 - 3000?F for two candidate materials to replace beryllium-copper.; BENEFIT: The anticipated results of this Phase I project will include material property database development for two candidate materials to replace beryllium-copper and the establishment of preliminary design concepts for their use within the high pressure wind tunnel. The material property database development will initially be derived from experimental results developed from previous and ongoing programs coupled with literature data. These databases will then be supplemented with experimentally-derived material property measurements to be performed in this proposed effort. The characterization will measure critical properties including thermal diffusivity (thermal conductivity, density, and specific heat), thermal expansion, Young?s modulus, and tensile strength/strain capability at select temperatures within the range of 75 - 3000?F. The preliminary designs will define theoretically attractive design options for the entire wind tunnel nozzle assembly, including the identification of any necessary modifications to the existing materials and hardware. This proposed STTR fits into MR&D?s expanding role as designers of advanced materials for extreme environments for demanding commercial and aerospace/defense applications. Technical success in this proposed effort will further enhance our position of offering unique and desirable design and analysis technology. Since MR&D is a design service-based company, the designs that we develop become the property of our customers. Thus the MR&D business plan does not envision growth in terms of numbers of fabricated components or growth in sales of developed software products or database systems. Rather the proposed Phase I program will result in design expertise coupled with applicable fabrication and experimentation that ultimately can be used to assist the Air Force. Additionally the high pressure wind tunnel design knowledge gained by MR&D from the Phase I program will open new opportunities to provide design and analysis services for various potential customers.