Abstract. Describing the combustion of log wood and others solid fuels with complex geometry, considerable water content and often heterogenous struture is a nontrivial task. Stochastic Cellular Automata models offer a promising approach for modelling such processes. Combustion models of this type exhibit several similarities to the well-known forest fire models, but there are also significant differences between those two types of models. These differences call for a detailed analysis and the development of supplementary modeling approaches. In this article we define a qualitative two-dimensional model of burning log wood, discuss the most important differences to classical forest fire models and present some preliminary results. Keywords: cellular automata, stochastic modeling, combustion
Introduction: The Role of Log WoodBiomass is an important source of renewable energy; the efficient use of biomass will be essential to achieve the transition to a lifestyle based on renewable resources. In order to reach the European 20-20-20 goals [1], about half of the demand for renewable energy will have to be covered by biomass. More than half of this amount will presumably be used in domestic smallscale combustion systems.While pellet technology -promising better control and lower emissions than traditional wood combustions -is on the rise, log wood is still an important fuel and will presumably remain to be so for decades to come. A main advantage of log wood is an economic one: Since less processing is required, log wood has a lower price than pellets. Also stoves tend to be cheaper. At the same time, less volume is needed for storing wood logs than for storing wood chips, an even cheaper renewable fuel. Also the handling of wood logs is easier than that of wood chips.The combustion of wood logs, however, is a complex process which involves transport processes, chemical reactions and heat transfer processes within complex geometry. There has been put quite some effort in the development of models for combustion of woody particles, in particular shrinking-core and reacting-core models [2,3,4,5] and CFD-related approaches based on partial differential equations [6,7]. These models grasp some important aspects of wood combustion, but they cannot (yet) incorporate the often complex geometry of wood logs. Complementary modeling approches, as the one presented in this article, may help to improve this situation.