Numerical Investigation of an In-Wall Cooling Design Approach for Improved Thermal Efficiency of Additively Manufactured Gas Turbine Ring Segments

Abstract Raising the combustion temperature continues to be a major driver for increasing the overall efficiency of industrial gas turbines. Therefore, active cooling has become a necessity as gas temperatures have surpassed the allowable temperature of the base material. Thus, cooling schemes need to be improved for higher heat loads. However, the thermal efficiency of cooling schemes, which can be manufactured employing conventional machining is limited. With the geometrical freedom offered by Additive Manufacturing (AM), advanced cooling designs for gas turbine parts have become viable and can provide superior thermal efficiency. A promising cooling design approach which exploits this freedom is In-Wall cooling. Here cooling channels are placed within the structural wall close to the heat-loaded surface. In order to develop this design approach further, In-Wall cooling schemes for a ring segment have been modeled numerically with different topologies and varying design parameters. These include wall thickness, channel pitch, size and length, and several more. The design parameters’ influence on thermal efficiency of In-Wall cooling schemes are quantified. The wall thickness between channels and the heat loaded surface is adapted locally. The employed approach leads to a more homogeneous temperature distribution and is reported in the paper. This work can help designers to focus on the most important factors when designing a new In-Wall cooling scheme and shows how the capabilities of AM can be employed in gas turbine cooling design.