Influence of the hub flange plate inlet fillet radius on the aerodynamic performance of a turbine

As the seal gas on the hub would produce certain influence on the flow field configuration and aerodynamic performance of a turbine, a numerical simulation method was used to study the influence of the hub flange plate inlet fillet radius on the aerodynamic performance and inner flow configuration at different seal gas flow rates. The research results show that any change of the fillet radius can lead to a change in the seal gas flow in the seal chamber and its transmission trajectory in the passages of the turbine as well as a change in evolution of the passage vortexes in the turbine, further causing a change in the distribution of the load coefficient, reaction force and flow coefficient of the turbine stage. Eventually, the aerodynamic performance of the turbine will be affected. For the cases calculated by the authors, the range influenced by a change in the hub flange plate inlet fillet radius on the turbine efficiency can reach 0.3%, indicating that the influence of the fillet radius will be enhanced with an increase of the seal gas flow rate.