Investigation On Flow And Heat Transfer Characteristics In The Tip Region Of Turbine Rotor

Gas turbines play an important role in the energy and aerospaceindustry, and are closely related to the defense industry. To improve thethermal efficiency and power of gas turbines is an issue of strategicimportance. By analysis of thermodynamic cycle, we can see that thethermal efficiency and power of gas turbines will improve with the hence ofturbine inlet temperature. The first stage of gas turbines is underenvironment of high temperature, which exceeds heat bearing of existingmaterials. In addition，because of complex flows in tip clearance there arelarge areas with high heat transfer coefficient in the tip region of turbineblades. Therefore, in order to improve the performance of gas turbines, it isnecessary to deeply investigate flow and heat transfer characteristics in thetip region of turbine blades.In this paper, experimental and numerical methods were used to studyflow and heat transfer characteristics in the tip region of turbine blades, andvarious factors were analyzed which can influence tip flow and heat transfer. The main contents are as follows:1. A detailed extraction of first stage blade profile data of GE-E3aero-engine’s high pressure turbine was conducted, and bladegeometry was draw up. Test pieces were processed on the basis ofthe blade profile which was magnified three times. And a rotatingturbine experiment table was set up.2. Heat transfer coefficient was measured using experiment ofnaphthalene sublimation. Firstly, experiment of heat transfer on aplate was carried out to verify the experiment principle and tocalibrate the measurement method. Then experiment of heattransfer in the tip region of turbine blade was completed and heattransfer coefficient distribution in the tip region was obtained.3. Calculations were performed to simulate the tip heat transfer on theexperimental blade model using different turbulence models. Alsoheat transfer coefficient distribution in the tip region was obtained.Comparisons between calculation results of different turbulencemodels and experimental results were performed. The goodturbulence model was chose as the standard model in the nextcalculations.4. Calculations were performed to simulate the tip flow and heattransfer on the GE-E3first stage high pressure turbine rotor. Flow field and heat transfer coefficient distribution in the tip region ofturbine blades were obtained. Areas of large heat transfer rate wereidentified on the blade tip and the mechanisms of heat transfer werediscussed. Tip structures, heights of tip clearance and inlet shroudboundary layers were considered for their impacts on the tipleakage flow and heat transfer. Also aerodynamic losses of turbineblades caused by leakage flow were analyzed.