The use of proper orthogonal decomposition in the research of combustion instability
Abstract
Combustion instability has been studied for decades but accurate modeling of the combustion's response to fluctuations in the pressure and velocity fields is still an arduous task. Proper orthogonal decomposition (POD) is a tool that has been gaining popularity and has promise to assist in modeling the response of combustion. Proper orthogonal decomposition (POD) was applied to high-speed video footage taken from combustion in a gas turbine engine designed to induce instabilities. The light from combustion was filtered to permit only CH* chemiluminescence, which was taken to represent qualitative rates of heat release. The orthogonal basis functions returned by performing POD on the video footage contained the responses of the system to the mechanisms that contribute to the addition of unsteady heat release. Some basis functions are similar and must be grouped together to reconstruct responses. The strongest responses came from the most influential acoustic modes. These responses can be attributed to either fluctuations in the pressure or oscillations in the velocity field. Responses to other non-acoustic sources can also be captured in these basis functions. The results of POD were extended to methods and techniques currently in use to further analyze the specific responses of the system. Transfer functions and Rayleigh indices were calculated for each response. Reduced-order models are built from the basis functions to create accurate approximations of the raw data.
Degree
M.S.A.A.
Advisors
Anderson, Purdue University.
Subject Area
Aerospace engineering|Mechanical engineering
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