Pressure and temperature effect on hypergolic ignition delay of triglyme-based fuel with hydrogen peroxide

In this study the effect of fuel temperature and environmental pressure on hypergolic ignition delay of triglyme (triethylene glycol dimethyl ether) with the addition of sodium borohydride and hydrogen peroxide was investigated. The research was conducted in a constant volume chamber using a drop-test method where the oxidizer drop was released into the fuel pool. The environmental pressure (absolute) was 0.1, 0.5, 1, 1.5 and 2 MPa; while the fuel temperature was 22, 40 and 60 °C. The main advantage of this study is that the effects of pressure and temperature were not investigated separately but the tests were done for full matrix conditions. This allowed the evaluation of the effect of fuel temperature at ambient and elevated pressures, and the effect of environmental pressure for ambient and elevated fuel temperatures, based on direct ignition delay measurements, a unique feature of this research. Additionally, the dispersion of the results was analysed in terms of repeatability of droplet parameters i.e. Weber number, as well as the diameter and velocity separately, along with eccentricity. The results have shown a huge influence on the ignition delay of both the fuel temperature and the environmental pressure. It was noticed that the average values of the Weber number and the droplet eccentricity remained at a similar level for all measurement points.