Use of CFD simulation as a design tool for biomass stoves

Design of biomass stoves has relied mostly on empirical information and trial-and-error experiments backed up by simple thermodynamic and heat transfer calculations. Quite frequently, the details of fluid flow inside the biomass stove, which is caused by buoyancy due to the high temperature prevailing in the combustion region, have been ignored and correlations of heat transfer based on forced flow have been used in the heat transfer analysis of stoves. This paper presents an approach in which detailed CFD simulations of the flow, heat transfer, pyrolysis and combustion in the configuration of a simple sawdust stove are used to evolve simple algebraic equations that describe individual phenomena. Such equations are needed in the field for performance analysis and prediction, and could also be used for the optimization of stove geometry for performance. The paper describes the development of the building-blocks of the detailed simulation model and its use in the derivation of simple model equations relating design and performance parameters.