Heat transfer in the trailing region of gas turbines – A state-of-the-art review

Abstract

• Review of flow structure and heat transfer of various cooling structures in trailing edge of gas turbines. • Summary of thermal performance of various cooling structures in trailing edge of gas turbines. • Trends for pin fin, latticework duct, dimple/protrusion and film cooling are provided. Highly efficient gas turbines are beneficial for improving the energy structure, reducing carbon dioxide emissions and protecting the Earth's environment. A highly efficient gas turbine means a higher inlet temperature and requires a more efficient cooling structure. Due to the limitations of aerodynamics, structure and strength, cracks, fractures and ablation easily form at the trailing edge of gas turbines. Thus, it is vital to enhance the heat transfer in the trailing edge of gas turbines. In practical applications, internal cooling structures (pin fins, latticework ducts) and film cooling are used simultaneously. In addition, some innovative cooling structures have been proposed, such as dimples/protrusions, labyrinth channels and so on. Research progress on turbine trailing edge cooling structures is presented in this paper. For pin finned duct, the heat transfer and flow structure characteristics are introduced for single rows, multirows, static and rotating conditions. Investigations on latticework ducts are quite inadequate. Therefore, only the main flow and heat transfer characteristics are shown in this paper. For film cooling at the trailing edge, experimental results and numerical results are introduced. Finally, some suggestions for heat transfer research in the trailing edge region are proposed.