Injection of supercritical ethylene in nitrogen
Injection of supercritical ethylene in nitrogen
复制标题
DOI：
10.2514/6.1995-382
复制
发表时间：
1995-01
期刊：
影响因子：
--
通讯作者：
P. Wu;Tzong H. Chen;A. Nejad;C. Carter
中科院分区：
文献类型：
--
作者：
P. Wu;Tzong H. Chen;A. Nejad;C. Carter
对静止气体环境中超临界燃料的喷射进行了实验研究，以阐明临界点附近的热物性和输运性质对射流外观、激波结构和堵塞的影响。用乙烯和氮气模拟燃料与空气的相互作用。考虑了乙烯热力学临界点附近的条件，包括喷射器上游的超临界温度和压力，以及喷射器下游的亚临界压力。流动显示显示，当燃料在接近室温的温度下喷射时，燃料凝结形成不透明区域。在较高的喷嘴温度下，发现乙烯射流具有类似于欠膨胀理想气体射流的激波结构。质量流量对背压的变化不敏感，表明射流被堵塞。在相同条件下，质量流率由理想气体射流的计算值归一化。当喷射条件接近临界温度时，归一化质量流量首先增加，这显然是由于流体密度的迅速增加，然后又减小，这可能是由于喷嘴出口处的液、气相共存所致。
The injection of supercritical fuel into a quiescent gas environment was experimentally studied to elucidate the effects of thermophysical and transport properties near the critical point on jet appearance, shock structures, and choking. Ethylene and nitrogen were used to simulate interactions between fuel and air. Conditions near the thermodynamic critical point of ethylene are considered, with supercritical temperatures and pressures upstream of the injector and subcritical pressures downstream of the injector. Flow visualization showed an opaque region resulting from fuel condensation when fuel was injected at near room temperature. At higher injectant temperatures, the ethylene jet was found to have a shock structure similar to that of an underexpanded ideal-gas jet. Mass flow rates were found to be insensitive to the variation of back pressure, indicating that the jet flow is choked. Mass flow rates were normalized by those values calculated for ideal-gas jets under the same conditions. The normalized mass flow rate first increases as injection conditions approach the critical temperature, apparently because of the rapid increase in fluid density, and then decreases, possibly as a result of the coexistence of liquid and gas phases at the nozzle exit.