Probe method for sampling solid-propellant combustion products at temperatures and pressures typical of a rocket combustion chamber

The paper describes a new probe method for determining the quantitative composition of solid-propellant combustion products at temperatures of 2500–3200 K and pressures of 4-8 MPa under conditions typical of rocket motor conditions. A two-step probe is described, which allows a sample to be frozen without passing through the main shocks inside the sampler. The gas dynamics and the kinetics of chemical reactions were simulated to asses the correctness of sampling. It is shown that during sampling from a flame, the relative change in concentrations for most of the stable components does not exceed 3%, and for H$_2$ and O$_2$, it does not exceed 12%. The method permits additional operations with a sample, in particular, separation of CO and N$_2$ with subsequent analysis on a time-of-flight mass spectrometer. The CO and CO$_2$ concentrations in the combustion products of the model composite solid propellant – ammonium dinitramide (ADN) with polycaprolactone ($p$CLN) – were determined at a pressure of 4 MPa.