Laboratory-Scale Thermal Stability Experiments on RP-1 and RP-2

The thermal stability of kerosene-based rocket propellants enables successful regenerative cooling of liquid rocket engines. This work experimentally investigates the effect of sulfur level and red dye concentrations on the thermal stability of RP-1 and RP-2 rocket fuels. A high Reynolds number thermal stability test unit evaluated various compositions of the fuels. The experiment consisted of an electrically heated, stainless steel capillary tube with controlled fuel outlet temperature. As deposits built up inside the capillary tube, an optical pyrometer monitored external temperature profiles. Multiple runs at individual test sites provided results on measurement repeatability. Testing at two facilities provided results on measurement reproducibility. The technique is able to distinguish between RP-1 and RP-2 rocket fuels which mainly differ in their sulfur concentrations. Red dye is shown to have a measurable negative impact on thermal stability. Carbon burn-off analysis of residue in the capillary tubes correlates with the external temperature results.