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Attention is paid to the influence of a secondary flow structures, such as generated vortices and flow in shroud-seal gap. The flow path consists of an input nozzle, stator blade-wheel, rotor blade-wheel, a shroud-seal gap and a diffuser. The proposed numerical method is used for solution of the 3D, unsteady, viscous turbulent flow of a perfect gas in the axial turbine stage. The temporal integration is based on the implicit second-order backward Euler formula, which is realized through the iteration process in dual time. The numerical code is based on a finite volume discretization of governing equations (Favre averaged Navier-Stokes equations and a two-equations turbulence model. The solution is performed using an in-house numerical code developed in the Aeronautical and Test Institute, Plc. Simulation of a 3D unsteady flow in an axial turbine stageįull Text Available The contribution deals with a numerical simulation of an unsteady flow in an axial turbine stage. The efficiency of the axial stage in dependence on the expansion ratio, velocity ratio and the configuration as well as the details of the flow fields are presented in this paper. The influence of the radial gap was studied in two configuration a positive and b negative overlapping of the tip-ends of the rotor blades. Numerical modelling was carried out for both the steady flow using the ”mixing plane” interface and the unsteady flow using the ”sliding mesh” interface between the stator and rotor wheels. The experiment was performed on the test rig equipped with the water brake dynamometer, torque meter and rotatable stator together with the linear probe manipulator. This problem was studied by experiment as well as by numerical modelling. In this configuration the flow through the radial gap under the hub-end of the stator blades and above the tip-end of the rotor blades leads to generation of the strong secondary flows, which decrease the efficiency of the stage. The investigation was carried out for the axial stage of the low-power turbine with the drum-type rotor without the shroud. Investigation of flow in axial turbine stage without shroud-sealĭirectory of Open Access Journals (Sweden)įull Text Available This article deals with investigation of the influence of the radial gaps on the efficiency of the axial turbine stage.