Investigation of Thermal Performance of AM Channels and the Influence of the Printing Angle.

Higher turbine temperature leads to higher efficiency. Therefore, in turbine technological development, the focus is to obtain advanced materials and cooling performance to withstand these high temperatures. Hence, as additive manufacturing allows the design of complex cooling patterns, with the employment of superalloys, that technology gained a foothold in gas turbine development. It is known that the side effect of AM is the presence of surface roughness, which, on one side, improves heat transfer but, on the other side, raises friction and causes pressure losses. For that reason, this study aims at understanding the correlation between the printing input values of selective laser melting (SLM), like material and printing angle, and hydraulic and cooling performance. This objective has been pursued through the experimental investigation of straight AM channels using the Darcy friction factor and Nusselt dimensionless number. Analysing the comparison between these two dimensionless numbers, the results for straight conduits show growth of heat transfer with surface roughness, regardless of the material employed. The results of printing angle variation show lower pressure losses with 0˚ and 45˚ printing angles than with 90˚ printing angle, which was an unforeseen behaviour based on what was expected from literature results.