Multi-jet impingement cooling in the leading edge of turbine blade using matrix as internal structure

Abstract

Multi-jet impingement is a competitive cooling scheme for the turbine blade leading edge, due to its strong ability in suppressing thermal boundary layer and quickly releasing the thermal load. However, crossflow is always a challenge if thermal performance is expected to be further improved. This paper proposed to induce jet flow from matrix to enhance cooling capability as well as uniformity of leading edge. A dual-air-paths test rig is built to measure heat transfer distribution and to validate the computational method. The results indicated strong coupling between jet cavity and matrix, implying the potential of enhancing heat transfer on both ends. Comparisons are made between different jet hole locations, among which the “Stagnation” position yields best performance, since superior initial jet condition can be created by matrix sub-channel flow. Increasing jet hole aperture leads to elevated heat transfer of nearly 72% in jet cavity, due to more stable vortex scour on the target wall. Changing jet cavity outflow configuration has significant effect on heat transfer due to thorough reconstruction of thermal field. The most advanced performance is acquired by both-sides outflow configuration, with approximately 34% improvement in heat transfer compared to the single-side cases.