Comparison of calculated and experimental delay periods of thermal autoignition τ of rocket propellant samples of NEPE type with characteristic sizes from 20 to 100 mm is presented. The experimental data obtained in the isoperibolic regime are taken from literature sources. In our calculation we used the model of chain reaction of thermal decomposition of nitroether plasticizers in NEPE composition. The calculated values of τ depend weakly on the sample size, but they are significantly (for small sizes – several times) smaller than those obtained in experiments. It is shown that the reasons for the discrepancy between the calculated and experimental values of the autoignition delay periods were the loss of active particles – decomposition products of nitroethers (primarily NO) both due to interaction with stabilizers and due to their migration into the environment due to leaky packing of samples. The role of migration phenomena is considered on the example of the solution of the diffusion equation, which takes into account the nucleation, multiplication and death of active particles.
A.A. Koptelov (Wed,) studied this question.