Theory of supercritical flames with real-fluid equations of state

We report a theoretical analysis of the propagation and structure of the planar adiabatic/radiative flame in supercritical fluids, employing the Van der Waals and the Redlich-Kwong equations of state to describe the fluid properties. It is demonstrated that the effective molecular volume and attractive force terms in these non-ideal equations of state show opposite effects on the density modification, especially in the upstream unburned region. Furthermore, the non-ideal effect is found to strongly couple with radiative emission and reabsorption, whose respective weakening and strengthening effect can substantially affect the state of radiation-induced quenching. The theory is useful for the description of high-pressure flames as both the non-ideal state and radiation become more pronounced under such conditions.