Abstract: Supercritical hydrocarbon fuels were being considered for use as coolants in high-performance aircraft. However, oscillations may occur at supercritical pressures, which may bring safety risks. This study included experimental investigations of supercritical pressure hydrocarbon fuels flowing through vertical heated channels with measurements of the transient local wall temperatures, bulk inlet and outlet fluid temperatures, mass flow rates, absolute inlet pressure and pressure difference across the test section. The transient response of the outlet temperature with a step input heat flux was a one order response. High heat fluxes resulted in oscillations of the inlet pressure and the outlet temperature. The sub-pseudo-critical number and the true trans-pseudo-critical number were used to characterize the oscillation conditions.

Key words: supercritical pressure fluid, transient response, convection heat transfer, instability

摘要： 冲压发动机所使用的再生冷却技术将超临界压力碳氢燃料作为冷却剂, 对其传热特性的研究很有必要。对竖直圆管中碳氢燃料的瞬态加热过程中的流动特性开展了实验研究, 测量了壁温、进出口流体温度、进口压力、进出口压差等参数的变化, 得到了基本的响应特性。实验中发现周期性的压力、流量、温度振荡现象, 并得到了出现该现象的临界实验参数。

关键词: 超临界流体, 瞬态响应, 对流换热, 不稳定性