Large eddy simulation of pulsating film cooling on turbine vane

Abstract

In this study, the large eddy simulation (LES) was employed to investigate the interaction mechanism between pulse jet and mainstream flow in turbine vanes, with a focus on assessing the impact of pulse frequency and amplitude on film cooling heat transfer. The results indicate that on the pressure surface, introducing pulsating coolant under high blowing ratio can effectively reduce the wall temperature, especially when using high amplitude pulse. Pulse excitation significantly affects the velocity distribution in the near-wall region of the pressure surface, while the velocity distribution on the suction surface shows less sensitivity to pulse excitation. Compared with the continuous condition, introducing pulsating coolant increases the turbulent kinetic energy (TKE). Higher pulsating amplitudes lead to a more pronounced enhancement of TKE, particularly on the pressure surface. Transient studies demonstrate the absence of starting vortices on both the pressure and suction surfaces during sinusoidal pulsation excitation. Although the evolution process of the turbulent structure of the two surfaces is completely different, the pulsating coolant under sinusoidal excitation can make the flow field have obvious periodicity. Analysis of the Power Spectral Density (PSD) reveals that coolant pulsation markedly affects the energy distribution of small-scale vortices.