Plasma Discharge Effects on the Breakup of a Liquid Jet in Supersonic Crossflow

Supersonic combustion ramjets (scramjets) are a promising propulsion system for hypersonic aircraft that require further research and development to maximize their stability and efficiency. Scramjets that utilize liquid hydrocarbon fuels have many practical benefits, but they suffer from a high level of complexity in the breakup and atomization of the liquid in supersonic flow. Scramjet efficiency is largely dependent on the quality of breakup and mixing of fuel upstream from combustion. With only a few milliseconds of residence time, it is vital to employ optimal strategies for fuel injection and atomization. Plasma discharges have been studied extensively in compressible flow control applications. In this study, spark discharges and dielectric barrier discharges (DBD) are tested upstream from a water jet transversely injected in a Mach 2 flow. Their effects on penetration height and the primary breakup of the jet is investigated. Direct, Schlieren, and spectral imaging are performed to characterize the plasma discharges and the liquid jet.