Methods of cooling turbine blade in aircraft fourth-generation turbine engines

<ns3:p>The aim of the article is to review and analyze existing methods and design solutions of high-pressure turbine cooling systems used in fourth-generation engines. The need to increase the temperature of the working medium causes the development of cooling systems, which also targets minimizing the negative impact of cooling on turbine efficiency. The paper presents the idea of cooling and the most important heat transfer models connected to turbine blades. Attention was focused on analyzing two types of cooling, i.e., internal and external. In the case of internal cooling, the problem of directing the flow of the cooling stream was outlined. It was pointed out that it plays a major role in the area of heat transfer efficiency, which depends on the shape of the flow channel, as well as the Reynolds number for the cooling air. One of the latest solutions used for cooling high-pressure turbine blades, i.e., a system of Dimple Induced Secondary Flow, was presented. In the case of external cooling, attention was focused on the elements affecting the effectiveness of this solution, i.e. the geometry, arrangement, and also the angle of the cooling holes. Results on the comparative analysis of heat transfer coefficients for different configurations of cooling systems are summarized.</ns3:p>