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Highly Compact Supersonic Cruise Missile (SSCM) Engine Inlet
Navy SBIR 2012.1 - Topic N121-028 NAVAIR - Ms. Donna Moore - [email protected] Opens: December 12, 2011 - Closes: January 11, 2012 N121-028 TITLE: Highly Compact Supersonic Cruise Missile (SSCM) Engine Inlet TECHNOLOGY AREAS: Space Platforms, Weapons RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected. OBJECTIVE: Develop a highly compact, low cost inlet that can efficiently interface with a small, supersonic turbofan/turbojet engine. DESCRIPTION: As air vehicle speeds increase, air breathing engine and inlet technology follow through concurrent supersonic performance requirements. The recent ability to build smaller supersonic engines has established a void in small air vehicle inlet capability. A solution to decrease the overall footprint of supersonic inlets within next-generation Supersonic Cruise Missiles (SSCMs) is desired. SSCMs, like the Next Generation TOMAHAWK (NGT), are under consideration in response to Prompt Global Strike (PGS) requirements, which characterize engagement time with Time-Critical-Targets (TCTs). The main savings of decreased inlet volume within the air vehicle provides a direct correlation to the range capability of SSCMs through increased fuel storage. With increased standoff range and speed, the warfighter is better protected from the enemy as well as better prepared for tactical action. The highly compact inlet would provide a faster time to target with the SSCM, but maintain the current Tomahawk lethality and range capability. The compact, supersonic inlet should capture and manipulate freestream air to desired speeds and pressures at the engine face. Air breathing engines require subsonic flow at the engine face, typically around Mach = 0.4. Due to the inlet design slowing the supersonic freestream air at the inlet down to subsonic speeds for engine operation while maintaining separation-free flow, supersonic inlets tend to be long and heavy. The inlet development requires an optimization of inlet length and geometry. Inlet development should avoid mechanical shockwave manipulation as used in linearly actuating spikes by employing a fixed geometry. Mass flow capabilities will be refined when matched to a specific engine, but the preliminary inlet design should be scalable for a range of small, supersonic engine mass flow rates. Computer analytical tools like Computational Fluid Dynamics (CFD) utilizing 3D Navier-Stokes flow field calculations often can depict these inlet flow fields. The inlet should produce ample high total pressure airflow, or rather minimal pressure loss, at the engine face for optimum engine performance as seen by thrust output which correlates to fuel consumption and subsequently air vehicle range. The design should also account for minimizing inlet drag at off design speeds due to supersonic inlets having a higher drag than subsonic inlets at subsonic flow conditions. The inlet design effort is intended to provide an example of a feasible, compact, low cost, supersonic inlet geometry within the constraints of an SSCM, namely the NGT. The NGT and associated inlet should have a low development and unit cost and must fit within the existing surface ship and submarine launch systems. Nonetheless, the design should lay a developmental framework to easily adapt the inlet design to any compact application. A compact inlet study proves challenging in that desirable flow characteristics break down in highly manipulated, tight spaces. An inlet study will aid the design of SSCM efforts by saving upfront costs, reducing schedule, and decreasing the complexity of inlet and engine integration. PHASE I: Demonstrate feasibility of designing a supersonic inlet suitable for small (approximately 12-14 inch diameter) SSCM turbofan/turbojet engines operable up to Mach 2.5 and meeting constraints of being compact, lightweight, fixed geometry, and low cost. PHASE II: Develop and demonstrate a computer simulation prototype of the supersonic inlet to allow integration into the NGT. Materials development is not a concern. PHASE III: Deliver computer model and, if possible, physical models of supersonic engine inlets. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The availability of a compact, supersonic inlet could prove very useful when paired with small, supersonic engines in the commercial sector as it would provide for a preliminary design point for high-speed, small transportation. The technology would be critical for new air vehicle design attempting to minimize volume, weight, and drag while maximizing fuel efficiency. REFERENCES:
3. X. Montazel and D. Sitbon, "Prediction of Supersonic Inlet Performances with 3D Navier-Stokes Calculations," AIAA 1197-3147-536. http://pdf.aiaa.org/getfile.cfm?urlX=85%26%5D0%3BU%2BDN%26S7R%20WLV4WBQ%3A%2B64%5B8%26%5FOKM%0A&urla=%26%2A%22P%22%23%20NE%0A&urlb=%21%2A%20%20%20%0A&urlc=%21%2A0%20%20%0A&urld=%28%2A%22%5C%27%21P%2EJWAX%20%0A&urle=%27%28%22P%2F%23%20%3EJUP%20%20%0A 4. Simon, P. C. & Brown, D. W. (1957). Performance of External and Compression on Bump Inlet at Mach Numbers 1.5 to 2.0. NACA RM E56L19 http://naca.central.cranfield.ac.uk/reports/1957/naca-rm-e56l19.pdf 5. George L. Muller and Williams F. Gasko, "Studies of Drag-Reduction Methods for Subsonic Operation of Supersonic Inlets," Pratt & Whitney Aircraft, East Hartford, Connecticut, AIAA 43842-2969. http://pdf.aiaa.org/getfile.cfm?urlX=8%3CWI%277D%2FQKW%3E6B5%3AKF2Z%5CD%3A%2B82%2A%5C%26%5D%5FKH%0A&urla=%26%2A%22P%22%23%20NE%0A&urlb=%21%2A%20%20%20%0A&urlc=%21%2A0%20%20%0A&urld=%28%2A%22%5C%27%21P%2EJWAX%20%0A&urle=%27%28%22P%2F%23%20%3EJUP%20%20%0A KEYWORDS: Inlet; Supersonic Cruise Missile (SSCM); Next Generation TOMAHAWK (NGT); Computational Fluid Dynamics (CFD); Pressure Recovery; engine
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