Validation of CFD-models of gas turbine engine uncooled turbines

In the course of the work presented in the paper the agreement between the parameters obtained by methods of computational fluid dynamics and the values used in the JSC "Kuznetsov" in the mathematical model of a gas-turbine unit NK-36ST was verified. A lowpressure turbine and a free turbine of a stationary gas turbine plant were the object of research. During the research three computational models of turbines with different numbers of finite-element computational grids were devised that do not take into account the presence of the turbine cavities. The models of the first level contained approximately 450,000 items in one blade row, the models of the second level - approximately one million elements in one blade row, while those of the third level - about 2 000 000 items per one blade row. A model that includes turbine cavities was also constructed. Diagrams of pressure profiles, total temperature, flow angle and turbulent viscosity throughout the height of the flow section
derived from the preliminary CFD calculations were set as boundary conditions at the inlet of the turbines. The calculation was performed in the Numeca Fine/Turbo software package and resulted in obtaining the basic parameters of the flow in turbines. The dependences of the flow capacity of the turbine А, turbine efficiency, turbine pressure ratio, the outlet flow angle in absolute frame on the parameter n/C*эф were found on their basis. The influence of the calculated mesh dimensions on the results of turbine characteristics simulation was investigated. The effect of taking into account the turbine cavities on the design characteristics of the turbine in the process of simulation was also investigated. Recommendations for constructing computational models of uncooled axial turbines of gas turbine engines are developed, the possibility of optimization and preliminary calculations using models that do not take into account the turbine cavities is justified.