The influence of swirl angle and hydrogen mixing ratio on the performance of micro gas turbine combustor is discussed by numerical simulation based on computational fluid dynamics (CFD) method, the parameters such as combustion characteristics and pollutant emissions are analyzed. The realizable k-epsilon model is adopted for turbulence simulation, the combustion model is general finite rate model. The results indicated that increasing swirl number reduces the temperature and NO emission. As hydrogen content in the fuel increases, flame length is slightly shortened, temperature in the combustion chamber rises, and temperature distribution becomes more uniform, NO emission at central axis becomes highly, while CO2 and CO emissions decrease. When hydrogen mixing ratio is 50%, the maximum NO emission is about 3 times that of pure methane combustion, and CO2 mass fraction is reduced by 43.9%, moreover, outlet CO emission is reduced by nearly 70%. The hydrogen mixing ratio has a greater impact on pollutant emissions, the sensitivity level of NO and CO emissions to hydrogen mixing ratio reaches 0.25 and 0.39 respectively. As hydrogen mixing ratio and swirl number increases, pressure loss grows, and average turbulent kinetic energy on central plane gradually rises, mainly in outlet region and recirculation zone. Increasing swirl number makes the synergy better, but hydrogen mixing has little effect on the synergy distribution.

A micro gas turbine swirl combustor with protruded bluff body is proposed. Compared with no bluff body, the protruded bluff body can significantly improve the combustion performance. When the bluff body height is 40 mm and the length is 30 mm, the average outlet NO emission is reduced by 14.43%, the pressure loss is decreased by 5.96%, and the outlet temperature distribution factor (OTDF) is dropped by 31.93%. The influence of different bluff body lengths (15–30 mm) and heights (10–50 mm) on the combustion flow are numerically analyzed further. The results show that the change of bluff body structure will affect the performance of combustor. In the range of 15–25 mm, with the increase of the bluff body length, the scope of central recirculation zone becomes narrower, velocity near the inlet and pressure loss decrease, the OTDF and field synergy angle β both become larger. When the bluff body length grows from 15 mm to 30 mm, the average outlet NO emission increases by 36.74%. The range of the central recirculation zone is gradually widen, and the average reaction rate grows up with the increase of bluff body height. The synergistic effect becomes better, and the heat transfer capacity is enhanced. When the bluff body height grows from 30 mm to 50 mm, the average outlet NO emission reduces from 35.84 ppm to 25.65 ppm.