Flame propagation through three-phase methane-hydrate particles

A new mathematical solution for the laminar combustion of a spray containing three-phase particles is derived. The three-phase particles are represented by methane hydrate (MH) particles. These particles melt and evaporate following a spherical symmetric model that demonstrates the unique nature of that process. The methane-hydrate particles are uniformly distributed, yet the gaseous methane is not initially premixed, until they reach the particle depletion front. A one-dimensional, laminar flame then propagates into a homogeneous mixture of oxidizer, inert gases and small methane-hydrate particles. Characteristics of the laminar methane-hydrate spray combustion are examined at different methane-to-water mass ratio values within the particles. The methane-hydrate evaporation model serves as a building block for the evaluation of these characteristics. Previous constraints on the evaporation front are relaxed. Instead, the unique profiles of the evaporation process of the methane-hydrate particles are integrated over the entire evaporation period. Thus, an energy balance is employed to evaluate the flame location, velocity and temperature at which all liquid is evaporated. Using this approach it is shown that modeling the initial transient evaporation stage is crucial in MH and leads to non-linear evaporation characteristics. This in turn alters the dynamics of the supported flame temperature, location and velocity. Particle loading is shown to have significant impact on the evaporation and flame as well.