Investigation on the showerhead film cooling of the turbine vane considering combustor swirling outflow

The mutual interference between the combustor and turbine of modern aero-engines has gradually increased with recent advancements, and turbine cooling design considering the flow characteristics at the combustor exit has not been investigated thoroughly. More importantly, no effective solution has been proposed for the negative impact of swirling inflow on vane cooling. This paper presents a comprehensive study on vane leading edge cooling, where the region is most susceptible to the swirling inflow. The film cooling effectiveness (& eta;) of the showerhead film cooling is measured by PSP (pressure-sensitive-paint) technology, and flow characteristics are obtained by numerical simulation. Based on the in-depth analysis, a new film hole layout is proposed to suppress the negative impact of the swirl intake condition on film cooling. The results show that the swirling inflow changes the vane pressure distribution, leading to a significant radial deflection of the film. This causes the film to concentrate in the partial area of the vane, thereby increasing the film distribution inhomogeneity. The mass flow ratio increase only restrains the negative influence of swirling inflow on the cooling effect to a certain extent under the high swirl intensity intake condition (SN = 0.45). At SN = 0.45, an efficient showerhead cooling scheme is desired, and we propose a new cooling scheme to this end. According to the pressure distribution on the leading edge, the new film hole layout scheme can exhibit excellent inhibitory effect on the radial deflection of the film. Therefore, the new cooling scheme can increase the film coverage area and improve the uniformity of film distribution. The increase in surface-averaged film cooling effectiveness (& eta;sur-ave) is up to 23.1%. Furthermore, the new cooling scheme reduces the relative standard deviation of film cooling effectiveness by up to 24.1%. Thus, the proposed scheme highlights the influence of the combustor outflow on the showerhead film cooling, which can provide a reference for vane cooling design.