CREARE LLC — Department of Defense SBIR Phase I: AF103-196

Description

ABSTRACT: The performance of modern propulsion devices such as gas turbine main combustors and augmentors is largely dependent on fuel spray dynamics. Fuel sprays, usually involving a liquid jet emanating into a gaseous flow followed by subsequent breakup and atomization, are critically important to many performance metrics including thrust, efficiency, static stability, dynamic stability, observability, and emissions. Despite the importance of jet breakup and atomization, these processes are poorly understood and design approaches are largely based on correlations, yielding limited predictive accuracy. The ability to study fuel spray dynamics is limited by existing diagnostics which have difficulty penetrating the dense core region and discriminating between liquid and vapor fuel. In the proposed effort, Creare and the Massachusetts Institute of Technology (MIT) will investigate applying an emerging 3-D flow visualization technique to this problem called Wave Front Imaging (WFI). Laser-Induced Fluorescence (LIF) will be used in combination with WFI (WFI-LIF) to quantify liquid and vapor fuel below the imaging resolution of WFI. In Phase I, we will conduct proof-of-concept experiments using isolated fuel drops vaporizing in hot air. We will compare WFI-LIF with numerical simulations of the same configuration. In Phase II, we will further enhance and calibrate WFI-LIF and extend it to representative flow conditions. BENEFIT: Technology derived from this project will be in the form of a new and novel flow visualization technique to study spray atomization. This will provide new insights into the spray breakup and mixing process, ultimately leading to decreased development time and cost for future propulsion systems while improving performance. This technology will be relevant to a broad range of combustion applications beyond augmentors including military and commercial aircraft combustors and internal combustion engines.