The numerical simulation of swirl cooling is one of the promising and latest internal cooling approaches for gas turbines. Thermal and isentropic efficiencies with the best-designed chambers were investigated, considering a flow through internal swirl cooling channels for heat transfer and flow behaviour in single-stage and multi-stage (two– to three–stage) swirl cooling channels. These rectangular nozzles to round shapes nozzles are used for each three-stage designs to find the best design chambers. However, this investigation on the multi-stage swirl cooling with changing the different types of round shape nozzles concluded. The generally employed k -� turbulent model, with varying types of wall treatment, and 20,000 to 40,000 Reynolds numbers. In this simulation
work, a single-stage internal cooling was used and considered the baseline geometry for further studies of multi-stage configurations. This work investigated the pressure drop, heat transfer, and total thermal performance of each cooling chambers. Following the multi-stage cooling chambers, there are additional pressure drops that occur, and the cooling performance is observed. This research aims to improve pressure drops and enhance the cooling performance for multi-stage cooling chambers. The rectangular-shaped nozzles were modified to round nozzles, resulting in a significant improvement: 60% higher heat transfer and reduced pressure drop. These three stages
of swirl-cooling configurations can result in an average surface temperature along the entire leading edge that is around 40K lower than in the single-stage cooling chamber configuration.
However, significant improvements in heat transfer during the multi-stage swirl cooling analysis increased overall pressure losses. Nevertheless, if the bends linking the adjacent angles of the nozzle stages are new and rounded, the rounded shape will gradually reduce pressure loss. Following this, the thermal efficiency of the multi-stage swirl cooling configurations was higher than that of the single-stage configurations. Furthermore, the design features three-stage swirl cooling chambers, transitioning from a rectangular shape to a round shape nozzles, with three types of round shapes used, 2 mm, 4 mm,
and 6mm. In these three models, different types of boundary conditions are applied, changing the temperature distribution in each design. This investigation indicates that the 4 mm designs are the best design, with better pressure drop and heat transfer overall, across all variables.
