Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services,

more »

... torate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. pressure engines. However due to the unsteady chamber pressure, the PDE system will either be over-or under-expanded for the majority of the cycle, with substantial performance loss in atmospheric flight applications. Thrust augmentation, such as PDEejector configurations, can potentially alleviate this problem. Here, we study the potential benefits of using Magnetohydrodynamic (MHD) augmentation by extracting energy from a Pulse Detonation Rocket Engine (PDRE) and applying it to a separate stream. In this PDRE-MHD Ejector (PDRIME) concept, the energy extracted from a generator in the nozzle is applied directly to a by-pass air stream through an MHD accelerator. The air stream is first shocked and raised to high-temperature, allowing thermal ionization to occur after appropriate seeding. The shock-processing of the high-speed air stream is accomplished by using the high initial PDRE nozzle pressures of the under-expanded phase. Thus, energy could be efficiently transferred from one stream to another. The present simulations involve use of a simple blowdown model for PDE behavior, coupled to quasi-1D and 2D numerical simulations of flow and MHD processes in the rest of the PDRIME configuration. Results show potential performance gains but some challenges associated with achieving these gains. Unclassified b. ABSTRACT Unclassified c. THIS PAGE Unclassified SAR 23 19b. TELEPHONE NUMBER (include area code) N/A Standard Form 298 (Rev. 8-98) Pulse detonation engines (PDEs) have received significant attention due to their potentially superior performance over constant pressure engines. However due to the unsteady chamber pressure, the PDE system will either be over-or under-expanded for the majority of the cycle, with substantial performance loss in atmospheric flight applications. Thrust augmentation, such as PDE-ejector configurations, can potentially alleviate this problem. Here, we study the potential benefits of using Magneto-hydrodynamic (MHD) augmentation by extracting energy from a Pulse Detonation Rocket Engine (PDRE) and applying it to a separate stream. In this PDRE-MHD Ejector (PDRIME) concept, the energy extracted from a generator in the nozzle is applied directly to a by-pass air stream through an MHD accelerator. The air stream is first shocked and raised to high-temperature, allowing thermal ionization to occur after appropriate seeding. The shock-processing of the highspeed air stream is accomplished by using the high initial PDRE nozzle pressures of the under-expanded phase. Thus, energy could be efficiently transferred from one stream to another. The present simulations involve use of a simple blowdown model for PDE behavior, coupled to quasi-1D and 2D numerical simulations of flow and MHD processes in the rest of the PDRIME configuration. Results show potential performance gains but some challenges associated with achieving these gains.