Influence of evaporation tube scheme on the flow field and combustion characteristics in a micro gas turbine combustor

Abstract Micro gas turbines have broad application prospects because of their compact size, low emissions, fuel flexibility, and high reliability. This study focused on a typical reverse flow micro gas turbine combustor and designed six overall structural schemes of micro gas turbine combustors with different evaporation tube arrangements and lengths. Numerical simulations and combustion experiments were also conducted. The data show that a structural scheme in which the evaporation tube is at an angle of 45° to the combustion liner axis provides the best performance. This scheme allows for the formation of multiple swirling regions at the head of the combustion liner, decreasing the flow velocity at the head of the combustion liner from 70 to 20 m/s, thus effectively reducing the flow velocity; in addition, the combustor can organize combustion at a higher inlet flow velocity. This scheme shows the best combustion performance, and the combustion efficiency reaches more than 98%. Increasing the length of the evaporation tube strengthens the circumferential connection and performance of the combustor flame. This also results in an increase in the jet velocity exiting the evaporation tube. The higher jet velocity increases the velocity at the head of the combustion liner. This change affects the temperature distribution within the combustion liner. Specifically, it leads to an increase in the temperature gradient inside the liner.