The development of a combustor, designed to burn raw producer gas that is not subjected to conventional gas cleaning processes, is presented. The combustor had tangential fuel and air inlets that caused a swirling flow inside it in order to facilitate fuel-air mixing and flame stabilization. The mixing and combustion performances of the combustor are characterized herein experimentally and via numerical simulations. Both measurements and simulations indicated good fuel-air mixing, the presence of a stable flame over a range of operating conditions and complete combustion of fuel. Measurement of particulate matter concentration at the combustor exit indicated that the combustor conforms to Indian regulatory norms. (C) 2014 Elsevier B.V. All rights reserved.