Effects of effusion hole configuration on liner wall cooling effectiveness and combustion performance in a can-type combustor model

Abstract

Effusion cooling is a widely adopted technique for managing high-temperature environments in aviation and various industrial applications. This method involves directing cooling air over component surfaces to protect critical engine parts from thermal damage, enhancing durability, improving efficiency, and reducing thermal emissions. This study used different configurations of effusion cooling holes on the liner wall of a can-type combustor model to evaluate their effects on cooling and combustion performances. Numerical simulations were conducted using ANSYS Fluent 2024 R1, with the turbulence and combustion of methane fuel modeled using the Reynolds Stress Model and the steady flamelet approach of the nonpremixed combustion model. The simulation results revealed that effusion holes oriented at a tangent angle of 0° significantly enhanced liner wall cooling effectiveness by approximately 340.28 %. This configuration obstructed 77.71 % of the absorbed radiative heat flux, which led to a 47.81 % reduction in wall temperature. This improvement was attributed to the diminished strength of the dilution hole jets, which resulted in incomplete combustion, as evidenced by the mixture distribution and OH mole fraction profiles. Consequently, direct quenching effects were observed on the flame front in the secondary and dilution regions, resulting in an approximately 5.56 % reduction in combustion efficiency. Moreover, the lowest pattern factor value was obtained when designing the liner wall with effusion holes at a tangent angle of ±30°, compared to other effusion hole configurations. Similarly, injecting cooling air into the combusted flame through an effusion hole at a tangent angle of 0° resulted in a reduction of approximately 20.23 % in the thermal NOx emissions.