Cooling structure design of gas turbine blade by using multi-level highly efficient design platform

Abstract

In this paper, the internal cooling structure of a second-stage rotor blade is designed by using a multi-level highly efficient design platform. The design process is divided into schematic design and detailed design in sequence. The calculations of pipe-network and heat conduction are presented to preliminary evaluate the cooling structures derived from the schematic design stage. The flow field and heat transfer characteristics of the revised cooling structures are analyzed in the detailed design by using the three-dimensional conjugated heat transfer calculation method. Topological structure, mass flow rate, pressure distribution, heat transfer coefficient and temperature distribution of the cooling channels are presented. It is found that the schematic design results based on one-dimensional to three-dimensional solution method are in good agreement with the detailed design results. Meanwile, the introduction of the schematic design is helpful to shorten the cooling design cycle and reduce the dependence of the design experience. In this work, a five-pass serpentine passage with single cooling air inlet in the cooling system may lead to low flow rate at the trailing edge, which is prone to cause hot gas back-flow and local high heat load. The cooling system with a right-angle channel and a three-pass serpentine channel helps to distribute the flow reasonably and reduce the thermal gradient on the blade surface. The optimal cooling structure meet the requirements well. Compared with the uncooled blade, the average temperature of the blade decrease over 530 K with limited cooling air.