An Asymptotic Analysis of Radiant and Hypergolic Heterogeneous Ignition of Solid Propellants

摘要

An asymptotic analysis, in the limit of large activation energies, is presented for the ignition of a solid propellant undergoing an exothermic heterogeneous Arrhenius reaction with a gaseous oxidizer. The analysis is carried out for hypergolic or shock tube ignition conditions, and also for ignition under a radiant flux with in-depth absorption of the radiation. The asymptotic analysis illustrates how, for sufficiently large radiant fluxes, a short reaction stage, ending in thermal runaway, follows a much longer inert heating stage. A closed form expression is found to relate the ignition time to the radiant flux and physio-chemical propellant characteristics. An analytical expression is also found for the ignition time under hypergolic or shock tube ignition conditions. (Author)