Conjugated heat transfer simulation of a gas turbine with various flow rate of cooling air

Recently, it is getting to frequently to operate gas turbines under off-design condition to absorb power supply fluctuations from renewable powers. By operating the gas turbine at off-design point, the flow rate of the nozzle and blade cooling air can be varied. Therefore, it is necessary to understand the influence of the flow rate change of the cooling air on the deterioration of aerodynamic components to maintain the gas turbine in good condition. Conjugated heat transfer simulations of the 1st stage nozzle were conducted with flow simulation of the following stages. Numerical method was validated by comparing with the operation data at a working power plant. Results showed that the wall cooling efficiency of the nozzle guide vane (NGV) increased as the flow rate of the cooling air increased, whereas the gas turbine performance was maintained.