Thermal metamaterials are used in the design of thermal cloaks to achieve a series of functions, such as thermal invisibility and thermal concentration, representing a new approach for implementing energy transfer control in heat transfer processes. In this study, based on transformation thermodynamics, two functions, i.e., thermal rotation and thermal concentration, were set according to the time sequence and adopted the concept of spatial separation or space-sharing. Three cylindrical thermal rotary concentrators were designed by different spatial transformations. The numerical simulation results show that all three devices enable the concentration of heat flow in specific regions and alter the initial transfer direction of the heat flow. There is also no disturbance in the external heat flow transfer. These results effectively enrich the theory of transformation thermodynamics and provide different ideas for the subsequent study of thermal metamaterials.

Film cooling can continuously cover a layer of low-temperature gas film on the surface of hot-end components, thereby achieving the effect of isolating high-temperature gas, and can achieve a temperature drop of 600 K. As an advanced and efficient cooling technique, film cooling plays a crucial role in the process of turbine power and efficiency increase, with the key factor influencing its cooling performance being the configuration and arrangement of the film holes. This paper summarizes the design and arrangement of film hole configurations and discusses the potential directions for enhancing film cooling performance. Through analysis, the optimization of film cooling performance is mainly approached from two aspects: first, optimizing the hole configuration, which includes the study of shaped holes, enhancing the cooling performance of cylindrical holes using auxiliary structures, and forming a “reverse kidney-shaped vortex” structure by using a single combined film hole; second, optimizing the arrangement of the cooling holes on the turbine surface to achieve a more uniform and efficient distribution of the cooling film. Future development trends are primarily reflected in the following aspects: designing new, easily manufacturable, high-efficiency film hole configurations and further expanding their stable operating range is an important development direction. It is essential to validate the reverse heat transfer method, assess its applicable range, and, when experimental conditions exceed the applicable range, use related theories to correct its predictive performance. This is key to overcoming the bottleneck in film cooling prediction. It is critical to develop a film hole arrangement guideline that is suitable for various types of film holes and components with temperature differences at the thermal end, to fill the gap in future film cooling optimization design technologies. This study aims to provide new ideas for the optimal design of the cooling system and further improve the power and efficiency of gas turbines.