Accession Number : ADA259949


Title :   Numerical Studies for the RAM Accelerator


Descriptive Note : Final rept. 1 Jan 1990-30 Sep 1992


Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC LAB FOR COMPUTATIONAL PHYSICS AND FLUID DYNAMICS


Personal Author(s) : Oran, Elaine S ; Li, Chiping ; Kailasanath, K


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259949.pdf


Report Date : 23 Dec 1992


Pagination or Media Count : 19


Abstract : Time-dependent, multidimensional computations were performed to study basic issues related to the structure of shocks, detonations, and modes of combustion affecting the feasibility or performance of the ram accelerator. A focus was on understanding of the structure and stability of oblique detonations generated by oblique shocks in supersonic fuel-air mixtures. The simulations show that steady, oblique detonations can be stabilized in supersonic flows and that they have very complex, multidimensional structures. Basic elements of such detonation structure include: (1) a nonreactive, oblique shock, (2) an induction zone, (3) a set of deflagration waves, and (4) a reactive shock in which the shock front is closely coupled with the energy release. This structure is stable and resilient to disturbances in the flow in a wide range of flow and mixture conditions. The conditions under which the overall detonation structure becomes unstable have also been identified. Preliminary studies which compared extremely resolved Navier-Stokes simulations to a boundary-layer model indicate some fundamental disagreements between the model and the simulations which require further investigations to resolve.


Descriptors :   *NUMERICAL ANALYSIS , *MIXTURES , *FUEL AIR RATIO , *DETONATIONS , SIMULATION , STABILITY , COMPUTATIONS , MODELS , TIME , COMBUSTION , SHOCK , DEFLAGRATION , SUPERSONIC FLOW , FLOW , FUELS , BOUNDARIES , REGIONS , BOUNDARY LAYER , AIR , LAYERS , ENERGY


Subject Categories : Combustion and Ignition


Distribution Statement : APPROVED FOR PUBLIC RELEASE