To investigate dynamic flow instabilities of hydrocarbon fuel in thermal protection structure of the scramjet, experiment was conducted at the pressure of 1.5–3.0 MPa, heat flux of 190–250 kW⋅m⁻², and the charge pressure at the surge tank of 0.5–1.0 MPa. Three main types of dynamic flow instabilities, pressure drop oscillation, density wave oscillation, and thermal oscillation took place during some experimental conditions. The influence of hydraulic characteristics of the test loop on dynamic flow instabilities was discussed. It was found that dynamic flow instabilities were mainly affected by the hydraulic characteristics of the test loop rather than the heating section. Pressure drop oscillation with large fluctuation amplitude and long period occurred in the negative slope region of the pressure drop curve. Density wave oscillation appeared in the positive slope region with low flow rate. The fluctuation amplitude and period of density wave oscillation were much smaller than those of pressure drop oscillation. Dynamic flow instabilities were more intense at lower pressure and higher heat flux. The oscillation region was independent of the compressible volume. However, a large compressible volume could promote the fluctuation amplitude of both inlet mass flow rate and outlet fuel temperature.

为了研究超燃冲压发动机热保护结构中碳氢燃料的动态流动不稳定性，在压力为1.5-3.0 MPa，热通量为190-250 kW·m ^-2的条件下进行了实验。，调压罐的补油压力为0.5-1.0 MPa。在某些实验条件下，发生了三种主要类型的动态流动不稳定性：压降振荡，密度波振荡和热振荡。讨论了测试回路的液压特性对动态流动不稳定性的影响。发现动态流动的不稳定性主要受测试回路的水力特性的影响，而不是受加热段的影响。在压降曲线的负斜率区域中发生了具有大的波动幅度和长周期的压降振荡。在低流量的正斜率区域出现密度波振荡。密度波振荡的波动幅度和周期远小于压降振荡的波动幅度和周期。在较低的压力和较高的热通量下，动态流动不稳定性更加强烈。振荡区域与可压缩体积无关。但是，较大的可压缩体积会促进入口质量流率和出口燃料温度的波动幅度。