Unsteady Scramjet Heat Load

To ensure the success of mid-scale scramjet development efforts, it will be essential to include the effects of chamber pressure oscillations (i.e. instability) on the engine heat load. This will require the inclusion of both the oscillatory heat load that accompanies the pressure oscillations and the impact of nonlinear combustion instability effects on the heat load. This can be accomplished using UCDS process, which allows a quantitative assessment of the impact of chamber pressure oscillations on the scramjet thermal environment and allow developers to include sufficient thermal margin in the design to deal with oscillations in test or operation. In the Phase I effort, GTL will demonstrate the calculation of all three components of the heat load, including the quasi-steady heat load, the oscillatory heat load, and the increased “DC shift” heat load from the nonlinear effects. When these results are integrated with a thermal management code, it will be possible to accurately predict the heat flux and the thermal balance point of a vehicle. Using the sensitivity analysis capability of UCDS, it will also be possible to accurately determine the uncertainty and sensitivity of the scramjet thermal environment. BENEFIT: UCDS Process provides an effective and reliable means to predict the oscillation characteristics of a combustion device. Not only does UCDS answer the question of whether a system is stable or not, UCDS provides detailed insight into the oscillatory characteristics of the device. For example, UCDS can be used to calculate the wall heat load in a scramjet or other propulsion device. This insight is critical to the development process, since it allows engineers to assess the physical implications of the oscillations and make any design changes needed to ensure success. Since UCDS is built from a general formulation, it can be used to analyze practically any combustion device, including rockets (liquid, solid, hybrid), turbojets (combustors, augmentors), ramjets, scramjets, combined cycle engines and so on. Therefore, potential customers for UCDS services include government agencies, such as Air Force, MDA, NASA, Army, Navy, and DARPA, and propulsion system developers, such as ATK, Aerojet, Pratt & Whitney, Rolls-Royce, and many others.