超临界正十烷喷射到大气环境的喷射特性

研究了超临界正十烷(n-decane)喷射到静止常温常压大气环境中的近场射流结构及喷口附近的射流相变特性.研究结果表明,超临界正十烷喷射到静止大气环境中后会经历类似于理想气体不完全膨胀的过程,会在喷嘴下游产生马赫盘等激波结构,马赫盘的位置随喷射压力的提高而增大,而喷射温度对马赫盘位置几乎没有影响.当喷射温度较高时,超临界正十烷在喷嘴出口处直接进入气相区,没有凝结现象发生.而当喷射温度接近临界温度时,超临界正十烷会在喷嘴内部及出口处发生局部凝结,进入气液两相区. 

Injection characteristics of supercritical n-decane into atmospheric environment

The injection of supercritical n-decane into a quiescent atmospheric environment was experimentally investigated to study the jet structures and phase transition process near the nozzle exit.It was found that supercritical n-decane jets injected above the critical point underwent ideal gas-like expansion and exhibited visible Mach disk shock structures.The axial location of the Mach disk increases with the growing injection pressure,and the injection temperature has little effects on the axial location of Mach disk.The phase transition process analysis reveals that,the supercritical n-decane is penetrated directly into the gas region from the supercritical region at the nozzle exit,without passing through the two phase region at higher injection temperature.Supercritical n-decane condensation phenomenon occurs in the nozzle and the outlet,and the fuel passes through the two phase region when fuel is injected near the critical point.