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.