Heat transfer coefficient measurements on curved surfaces

This paper presents the results of experimental research on heat transfer distribution under the impinging jets at high jet velocity on curved surfaces. The air jets flow out from the common pipe and impinge on a surface which is cooled by them, in this way all together create a model of external cooling system of low pressure gas turbine casing. Preliminary measurement results from the flat plate case were compared with the results from the curved surface case. Surface modification presented in this paper relied on geometry change of flat surface to the form of a 'bump'. The special system of pivoted mirrors was implemented during the measurements to capture the heat exchange on curved surfaces of the bump. The higher values of mean heat transfer coefficient were observed for all flow cases with a bump in relation to the reference flow case with a flat plate.