Numerical Investigations Of The Compound Cooling For A Thermal Barrier Coated Nozzle Guide Vane

The main approach to improve the thrust and efficiency of gas turbines is to increase turbine inlet temperature (TIT). As the TIT of advanced aero engines has gone far beyond the bearable temperature of the present materials, the development of cooling techniques is the key solution. The past half century has seen the development and wide application of film cooling in turbine design industry. Given that the structures of cooling designs gain complexity, and cooling effectiveness reaches its bottleneck, thermal barrier coatings provide a high potential for the protection of turbine vanes. To accurately predict the life span of a vane, we need to obtain the precise information of the thermal load and thermal field. Numerical conjugate heat transfer serves as an ideal analyzing tool.The meshes in this thesis are generated using ANSYS ICEM, and numerical calculation is carried out by ANSYS Fluent and the SST k-? turbulence model. Studies have been done in the following areas:1) Verification of the approach resolving TBC on a flat plate with one row of film cooling holes which simulates the hub of a guide vane. By comparing the calculated temperature and heat flux of two strategies for TBC, we confirm that the algorithm in Fluent considering TBC is acceptable accuracy-wise.2) Under two near-engine operation conditions and three 3 different TBC strategies, the cooling performances of a highly integrated, compound cooled turbine vane are simulated using conjugate heat transfer algorithm. By showing the mass flow rate, surface temperature, overall cooling effectiveness, heat transfer coefficient, pressure and Mach number, detailed flow and thermal characteristics are analyzed.3) In the light of a set of specific main inlet and outlet pressure, main and cooling flow inlet temperature, the mass flow rate of coolant is decreased. Numerical analysis has been made to compare the effect of existence of TBC and coolant mass flow rate on the thermal characteristic of the vane. The results show that. TBC protects the leading edge effectively by reducing the metal surface temperature and that with equal mean surface temperature achieved. TBC can save the coolant mass flow rate by 20-30%.