Abstract: A gas turbine combustor burning LBTU fuel gas serves to be applied to the combustion system of a small turbogenerator. The combustion system is composed of a combustor outer case, a combustor liner, a combustor transition section, a radial swirler with adjustable blades and fuel supply passages. The small turbogenerator (10 KW) with the redesigned combustion system is integrated by a LBTU gas generator. A recirculation bubble with proper size and strength is aerodynamically formed by the interaction among the swirling air jet, inclined fuel jet and the primary jets. Since an adjustable swirler is installed, the swirl number of the swirling air jet can be modified to meet the requirements of combustion load sharing and burning different LBTU fuel gases. To eliminate the possible hot spots and thus reduce the pattern factor value, two rows of cooling jet holes are arranged in the rear section of the combustor.