Cooling and Flow Characteristics of Multi-Channel Wall Jet Structure With Film Holes at Blade Leading Edge

Abstract

Efficient cooling is imperative for gas turbine blades that suffer from hot gas erosion. Cooling and flow characteristics of multi-channel wall jet structure combined with film holes for blade leading edge are numerically investigated through the Reynolds-averaged Navier–Stokes method in this paper. Several geometrical schemes with different rows and diameters of film holes were conducted, and the influences of the cooling air mass flow ratio of the first coolant supply cavity were also considered, which presented the detailed flow and cooling characteristics of wall jet and film composite cooling on conjugate heat transfer. The results implied that film extraction improves the overall cooling effectiveness compared with pure wall jet cooling. And the mainstream intrusion happens in some film holes at the bottom of blades, especially on the pressure side. The film-hole diameter can raise the mass flow ratio and enhance external thermal protection produced by cooling air, and it also affects the uniformity of film flow and the temperature gradient of some regions for turbine blades. Furthermore, the cooling performance and pressure loss are significantly influenced by the coolant mass flowrate of the first cooling air supply cavity. This study will offer a consultation for the design of film-hole structures for multi-channel wall jet cooling.