COMBUSTION SCIENCE & ENGINEERING, INC. — Department of Defense SBIR Phase I: AF151-062

Description

ABSTRACT: Afterburners operate under a wide range of operating conditions and hence they are likely to encounter conditions at which combustion (thermoacoustic) instabilities occur. Therefore, methods to mitigate rumble and screech, usually classified as either active or passive control, are of clear interest. CSE, Inc. proposes to develop a strategy to design passive-control systems, in particular damping devices, to mitigate combustion instabilities in afterburners. Passive-control methods for afterburners have been under development for more than half a century. In spite of this plethora of passive-control devices and apparently good understanding of their basic physics, in particular for damping devices as highlighted above, the problem is that in practice passive control techniques tend to be applied on a (very) costly trial and error basis. CSE, Inc. proposes to develop a strategy to design passive-control systems, in particular damping devices, to mitigate combustion instabilities in afterburners. This strategy is centered around an acoustic solver and is assisted by theory and CFD simulations. However, the present idea of using theory and CFD to assist acoustic-solver simulations in the time-domain can be applied to the design of any active- or passive-control method, and to any type of combustor. BENEFIT: Passive-control methods for afterburners are currently designed via a costly trial and error process. Thus, there is a need for computationally tractable, design-specific analyses that could reduce these costs and, as a result, make the development of new devices more attractive. The obvious market for this software is the OEMs designing damping devices for afterburners. However, due to the broad range of applicability of the proposed strategy, it is applicable to any passive-control method and to any type of combustor. This feature enhances the commercial success of the proposed approach by making it more appealing to a broader market, that includes the expanding gas-turbine industry.