Modeling the Combustion of a Solid Fuel Containing a Liquid Oxidizer Droplet

DOI: 10.2514/1.B34488 This work presents a physical model of the combustion behavior of a liquid oxidizer droplet with adjacent solid fuel. It is the first modeling attempt related to a proposed new potential class of liquid-oxidizer-enhanced solid propellants, where liquid oxidizer units/capsules are embedded in a solid fuel/propellant, revealing a theoretical specific impulse increase of up to 12%. A one-dimensional mathematical model is formulated, which describes the main characteristics of the microscale flamelet formed by a volatile (typically polymeric) fuel component and an adjacent endothermically evaporating oxidizer droplet. The model predicts fuel and oxidizer surface temperatures, fluxes, and flame height as functions of operating pressure and droplet size. The transient nature of the combustion processisemphasized,revealingacombustioncycleattheindividualdropletscale,withpressure-dependentaverage burning rates typical to solid propellants.