Inhomogeneous behavior of supercritical hydrocarbon fuel flow in a regenerative cooling channel for a scramjet engine

Supercritical hydrocarbon fuel is employed to simultaneously cool associated combustors and to recover heat. Aiming to improve the thermal performance of the regenerative cooling channels in an advanced aircraft, the flow behavior, vortex structures, and transport characteristics of supercritical n-decane are investigated using an LES model. The flow patterns are identified by several common buoyancy criteria, and oscillation effects are observed in strongly mixed flows. Using temperature and density gradient fields, distinct inhomogeneity shows that the thermal oscillations aggravate the further occurrence of uneven performance. Furthermore, the positive helicity gradually increases with the accumulation of buoyancy force. The notably strong vorticity mainly concentrates near the heated wall, while a narrow section appears in the turbulent region, which indicates that the variable vorticity behavior contributes to the transport properties.