Critical Initiation of Oblique Detonation Waves by Finite Wedges

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Authors
  1. Verreault, J.
Corporate Authors
Defence R&D Canada - Valcartier, Valcartier QUE (CAN)
Abstract
In a shock-induced combustion ramjet, combustion relies on a standing oblique detonation wave at the entrance of the combustor. Assuming that the fuel is uniformly mixed with the air stream prior to reach this location, it is essential to predict the conditions (type of fuel, mixture equivalence ratio, flow velocity and deflection angle) to initiate such a detonation wave for various flight regimes. In this investigation, hypersonic reactive flows over finite wedges are simulated with a method of characteristics program. The chemistry is modeled with a single-step Arrhenius equation. The independent parameters are the freestream velocity, the wedge height and the wedge angle. At the critical conditions to initiate an oblique detonation wave, the critical wedge drag is calculated. In an attempt to develop a universal prediction tool without having to solve the flowfield, the Lee-Vasiljev model is considered. This model equates the work done by the wedge (the wedge drag) to the critical energy to directly initiate a cylindrical detonation wave. According to this model, the energy transfered by the wedge to the mixture is the only parameter that determines whether detonation initiation occurs or fails. The simulation results show three regimes (subcritical, critical and supercritical) that are typical to direct initiation of a detonation. The critical drag is obtained for a series of test cases. When the wedge angle is fixed and the wedge height is varied to find the critical dr

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Report Number
DRDC-VALCARTIER-CR-2011-277 — Contractor Report
Date of publication
01 Sep 2011
Number of Pages
42
DSTKIM No
CA037959
CANDIS No
537883
Format(s):
Electronic Document(PDF)

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