Numerical Analysis of Heat Transfer Characteristics According to Relative Positions of Swirler and First-stage Nozzle Vane of Turboshaft Engine Reverseflow Combustor

This study conducted a computational analysis to investigate the effects of the swirler’s rotational direction and relative position in a reverse-flow combustor—applied to a turboshaft engine—on the thermo-aerodynamic characteristics of the first-stage nozzle vane. Four cases were analyzed by varying the swirler’s relative position (either upstream of the vane mid-passage or the leading edge) and rotational direction (clockwise or counterclockwise). Numerical simulations were performed using ANSYS CFX 2023 R1 with the RANS-based k–ω SST turbulence model. The analysis focused on the distributions of convective heat transfer coefficients and vorticity around the vane. The results showed that when the swirler was located upstream of the vane passage and rotated counterclockwise, the swirl flow developed sufficiently along the passage, promoting stronger secondary flows and enhancing heat transfer on the vane surface. In contrast, when the swirler was positioned upstream of the vane leading edge, the swirl intensity weakened, resulting in lower overall heat transfer. Additiona lly, vortex structures were visualized using iso-surfaces to provide a three-dimensional assessment of how the swirler’s relative position and rotational direction influence the aerodynamic and heat transfer characteristics around the vane.