Mathematical model of the ignition of a gel organic fuel droplet interacting with a pool of nitric acid

An original mathematical model of the ignition of a gel tetramethylethylenediamine (TMEDA) droplet upon contact with a pool of highly concentrated nitric acid (WFNA) has been developed. The model is based on the results of the experimental studies and an analysis of existing mathematical models of the ignition processes of liquid hypergolic fuels. This mathematical model describes a group of interconnected physical and chemical processes in the condensed phase and gaseous environment (heat transfer, evaporation of components, their diffusion and exothermic reaction) to reproduce the dynamics of changes in temperature and concentration fields under non-stationary conditions. The reliability of the numerical solution is justified by the grid convergence analysis using the grid convergence index (less than 10% for the selected grid). The accuracy of the developed model is confirmed by comparison with experimental data: the maximum deviation of the calculated ignition delay times does not exceed 15% when varying the fuel particle sizes and 10% when changing the initial fuel temperature. A satisfactory agreement of the numerical simulation results with experimental data made it possible to establish the limits of applicability of the developed mathematical model. Numerical modeling allowed for expanding the key parameter variation range to determine specific process characteristics. These findings form the basis for developing hypergolic gel fuel combustion theory and its practical energy applications.