NASP Concept Demonstration Engine and Subscale Parametric Engine tests

Abstract

During 1993 and 1994, the National AeroSpace Plane (NASP) Program tested two nonflight-weight, hydrogen-fueled supersonic combustion ramjet (scramjet) engines in the midspeed (Mach 5-8 ) range in the Scramjet Test Complex at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC). The Subscale Parametric Engine, a 12.5-percent photographically scaled model of the NASP flight engine design, was tested in the Arc-Heated Scramjet Test Facility, and the Concept Demonstration Engine, a 30-percent photographically scaled model of the NASP flight engine design, was tested in the Eight-Foot High-Temperature Tunnel. These engine tests provided information on integrated engine and engine component performance, as well as on component interactions. The performance data from the engines were classified, therefore engine performance data were not discussed in this paper. The lack of complete flight simulation because of failure to duplicate geometric scale, dynamic pressure, and test gas composition, was discussed in relation to the simulation parameters governing scramjet operation. In the tests, Mach number was duplicated; and the first and second Damkoler numbers were simulated by duplicating flight total enthalpy and using a mixture of silane and hydrogen fuel to assure mixing-limited combustion. Test gas vitiation, which occurs during the test gas heating process necessary to duplicate fight total enthalpy, was shown to have little influence on the performance results. The simulation parameters that characterize viscous phenomena were not duplicated, but the resultant effects of drag, heat ‘Aerospace Rcscarch Engineer, Hypersonic Airhrcathing Propulsion Branch, Member AIAA. d transfer, and boundary-layer characteristics were determined during the engine data analysis process through the use of empirical, analytical, and numerical modeling.