A numerical study of trans-/supercritical fuel injection based on a generalized cubic equation of state

Trans-/supercritical injection has great potential for improving the formation of combustible gas mixtures and emission performance. In this work, based on the sufficient validation of the cur-rent numerical framework, we compared the Peng-Robinson (PR) equation of state (EoS) with the Redlich-Kwong-Peng-Robinson (RK-PR) EoS and applied them to simulate the injection events under trans-/supercritical conditions. The effects of different nozzle diameters and chamber condi-tions on jet characteristics and pseudo-boiling were investigated. The results indicated that RK-PR EoS has higher prediction accuracy. The fuel injection characteristics are significantly affected by the nozzle diameter and the time required to undergo the pseudo-boiling process becomes longer with increasing nozzle diameter. Compared with chamber temperature, chamber pressure has a greater influence on the fuel injection and mixture formation behavior. The high pseudo-boiling intensity caused by the low supercritical pressure significantly increases the jet length and reduces the mix -ing layer thickness. Moreover, unlike the single-component case, the mixing effect within a multi-component fluid influences both pseudo-boiling occurrence and its intensity.