Combustion characteristics of a micro gas turbine combustor with gamma-shaped porous media dome

During the past decade, increasing interest has been shown in micro gas turbines for the high-power and high-energy density. However, due to the small characteristic scale, it is still a key problem to ensure safe and reliable operation of the micro-combustor. A new micro gas turbine combustor with a λ-shaped porous media dome was investigated in this paper. The volume of the combustor is 2.7 cm³. Dual-zone combustion (combustion zone and dilution zone) was adopted in the combustor. Combustion characteristics of the micro-combustor with different total air mass flow and total equivalence ratios were investigated by experiments at ambient temperature and atmospheric pressure. The results show that the relationship between liner pressure-loss and total air mass flow cannot be fit by a polynomial due to porous media and dilution holes combined influence. The ratio of airflow across porous media dome to total air mass flow increased with increasing total air mass flow. Stable combustion was obtained in this micro combustor as the air mass flow rate was in the range of 0.15~1.2 g/s. With the increasing total air mass flow, the total equivalence ratios of lean ignition and blow-out limits decreased first, then increased. The exit gas temperature as high as 1460 K and power density 636 MW/m³ were achieved at the total equivalence ratio of 0.5, and total air flow rate of 1.2 g/s, the overall efficiency reached 98.5% in this condition. The results showed that safe and reliable operation can be achieved in this new micro gas turbine combustor with high overall efficiency.