Thermoacoustic instabilities found in rocket chamber combustors, date to the early development stage of rockets. Unsteady pressure wave oscillations caused by inhomogeneity in flame energy release, increases engine noise and decreases flame stabilization. These instabilities are detrimental to engine performances and can result in engine failure. Attenuation of the acoustic pressure oscillations plays a critical role for reduction in acoustic pressure wave instabilities. Tangential modes are the most damaging acoustic mode experienced in the engine. An investigation of offset injector baffles demonstrates acoustic damping enhancements for liquid rocket engine combustors. A series of offset baffle injector heights were tested to understand the effects on tangential acoustic mode waves. Under non-flow auditory conditions, acoustic mode analysis for baffle injector offset heights from 0 to 50 millimeters were studied. Offset injector baffles are a passive device that can reduce high acoustic energetic modes. This is attributed through the offset injector baffle height, due to shear layer entering the combustion chamber at different heights. Jet shear layer acts as an obstruction to pressure wave oscillations. However, the addition of offset injector baffle height creates shear layers at the end of the injector height and promotes greater impregnable height. Tangential (1T and 2T) modes are of particular interest, the suppression device was observed to dissipate acoustic amplitudes. Offset injector height was analyzed to define an optimal height that impacts tangential modes.
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