With continued increase of volatility of natural gas prices and concerns regarding national energy security, alternative fuels such as low calorific value (LCV) synthetic gases (syngas) derived from gasification of coal, petroleum coke, or biomass are considered as important common fuels in the future. This study specifically investigates the chemical combustion of LCV fuel in a combustion chamber, a tool of CFD (ANSYS/FLUENT) has been used to study the kinematics of chemical reaction. A combustion chamber has been modeled. In the current study, the goal is to simulate the combustion reactions of Natural Gas (NG) and LCV fuels and compare the results. Analysis is conducted with two LCV fuels: LCV1 and LCV2, which have approximately 8% and 15% of the NG heating values respectively. Both fuels are the mixture that contains similar compounds such as methane, ethane, and hydrogen, etc., but LCV2 does not contain nitrogen. The adiabatic flame temperature of LCV1 and LCV2 were both much less than NG due to a lack of purity and robustness of the combustion reactions, which requires improvements. The CO₂ and NOx gas levels in the entire domain of LCV1 and LCV2 cases were both found significantly less than the NG.