Study on the fuel jet evolution under trans/supercritical conditions and different environment pressure conditions

In liquid rocket engines or internal combustion engines, increasing the inlet fuels temperature or chamber pressure exceeding its critical point is capable of improving the combustion efficiency. Under these conditions, the thermophysical and transport properties have an important effect on fluids mixing and combustion process. In this study, the fuel of n-heptane injected into a multi-species environment are simulated by large eddy simulations and the performance of the injected fuel temperature and different chamber conditions are compared in conjunction with high accuracy equation of state and transport properties. The results show that as the injected temperature or the chamber pressure increase, the penetration length and density gradient decrease, while the width of mixing layer increase. The results obtained in this investigation indicated that for the single injection condition, by increasing the fuel inlet temperature or chamber pressure, the essence is to reduce the initial density ratio, thereby reducing the density stratification between the jet and environment gas, which is beneficial to the jet mixing and combustion process.