Experiment on heat transfer characteristics inside the casing of high pressure turbine with active clearance control

According to a typical heat transfer structure of the casing of a high pressure turbine with active clearance control system,experiments were conducted to investigate the local heat transfer characteristics of a mutillayer casing structure.In the experiments,the inlet Reynolds number (10000-24000),the angle of jet impingement (30°,45°,60°) and the diameter of jet impingement hole (1.0,1.5,2.0mm) were changed to investigate the local and average heat transfer coefficients of the casing surface with ribs.It was found that the existence of the ribs affected the local heat transfer coefficient of the casing surface significantly.At the same time,due to the local heat transfer enhancement by the jet impingement,the heat transfer coefficient of the casing inner surface varied considerably at different locations.The results show that the local and average heat transfer coefficients are improved with the increasing inlet Reynolds number of cold air.Within the range of research parameters,maximum heat transfer can be obtained when the diameter of the jet holes is 2mm and the number of jet holes is 23.Compared with the angle of jet impingement 30° and 60°,45 ° can result in higher heat transfer rate.