Aerothermal characteristics past a matrix structure inside a rectangular serpentine passage

Abstract

A matrix structure can offer a high heat transfer and improved structural rigidity to the gas turbine's aerofoils. The earlier matrix studies are limited to presenting aerothermal behavior within the matrix structures. Thus, there is a scope to investigate the aerothermal characteristics downstream of a matrix geometry. The present experimental effort seeks to characterize the detailed flow and heat transfer downstream of the matrix and at the bend for Re = 800 and 6500. The heat transfer and flow fields are captured in various planes using liquid crystal thermography and stereoscopic particle image velocimetry techniques. The results show that the matrix ejects a highly turbulent vortical flow in the form of two co-rotating vortices, which further diffuse and merge in downstream. The matrix offers a very high average augmentation (Nu¯/Nu¯0) in the first pass for Re = 800 (varies from 12 to 4), but it shows a poor heat transfer (Nu¯/Nu¯0 < 1) at the bend region, which can generate local hot spots for Re = 800. In contrast, for Re = 6500, the matrix offers a stable augmentation throughout the first pass and bend region, i.e., Nu¯/Nu¯0≈ 2.4–1.