Thermal Performance, Frictional Characteristics, and Energy Efficiency of Integrating Helical Diverters in Two-Pass Rotating Gas Turbine Blade Cooling Channels

Abstract In gas turbines, enhancing the cooling process of the turbine blades is vital for allowing the turbine to operate with finer performance and extending the operational lifespan of the turbine. This study explores the impact of integrating helical diverters (HD) as a passive cooling mechanism within a two-pass rectangular rotating cooling channel in gas turbine blades, numerically. Through a validated numerical model, this research will assess the impact of these diverters on heat transfer enhancement, frictional losses, and overall energy efficiency. The tests involve five main cases, with rotation numbers of Ro 0, 0.125, 0.25, 0.375, and 0.5, across a range of Reynolds numbers (20,000, 30,000, 40,000, 50,000). In some cases, the helical diverters enhance the heat transfer rates in the trailing and leading edge by stirring the flow and mixing different flow layers, thus facilitating more effective cooling. Nevertheless, the helical diverters are accompanied by increased frictional losses, translating into a rise in the air source’s power consumption. Additionally, the study explores how the helical diverters influence the Coriolis effect, a critical factor in rotating systems, revealing a reduction in Coriolis-induced flow deviations, thereby contributing to a more uniform temperature distribution across the blade. The helical diverters may achieve a 27% performance enhancement in stationary cases. In the rotational cases, the HD enhances the heat transfer performance inside the channel at a Ro threshold between 0- and 0.375. Moreover, at a high Ro number (Ro = 0.5), the normalized Nusselt number at the trailing edge is enhanced but the total pressure drop penalty degrades the performance of the helical diverters, at this particular rotation number.