Computational Fluid Dynamics (CFD) was used to study the characteristics of Fluidized and Stoker type combustion chamber. Besides experimental testing, computational works are nowadays becoming more important due to lower cost and acceptable accuracy with minimum error. Especially for newly developed model, the computational testing using CFD software will reduce a lot of trial and error on experimental work. The CFD analysis of Fluidized bed and Stoker type furnace with air flow was conducted. The simulation was carried out using ANSYS 17.0. The CFD analysis was conducted to study the possible clinkering caused by the specific localized high temperature zones.