In the present work, transient CFD simulations of full wood log combustion cycles have been performed to study the time dependent behavior in cast iron and soapstone wood stoves. A model for the gas release is developed and implemented. The gas release model takes into account that the fuel gas release is transient, where both mass flow rate and gas composition as well as gas temperature changes with time. The effect of the wood stove material and its thermal inertia and conductivity on the combustion process and the transient heat release to the surroundings has been studied. In addition, transient variation in gas and wall temperatures as well as the combustion performance, was also studied. The simulations clearly show the effect of stove type on the transient heat release, which is controlled by the outer wall temperatures and the amount of heat transferred into the walls and their heat storage capacity. Due to the long real time duration of a full combustion cycle, these simulations are computationally very expensive and therefore only two-dimensional simulations were performed. The results show that the cast iron stove has higher outer wall temperatures and heat release during the combustion cycle than the soapstone stove. The soapstone stove has flatter profiles for outer wall temperatures and heat release to the surroundings and have a longer heat release period after the combustion cycle has ended.
