Three-dimensional Mathematical Simulation of the Stator Slot of a Turbogenerator, Including Thermal Modeling and Flow Fluid Dynamics

In this article, the authors explain the principles of creating a three-dimensional symmetrical part of the stator slot of a turbo generator including thermal modeling and flow fluid dynamics. Various physics interfaces were used to create a complete numerical simulation model. To link variables in various physical interfaces, multiphysicists were used with their own differential equations. As a result of work in the COMSOL Multiphysics software, careful multiphysics mathematical models of the stator clot of the turbine generator were built. For the calculation in the program, the finite element method was used with the correct setting of the initial and boundary conditions. Building such complex models can not only improve the design process, but also enable analysis for various insulation systems. For example, air-cooled turbine generators initially use the Global VPI insulation system, but when replacing the stator winding, for economic reasons, a different insulation system is used - Resin Rich. For a correct transition to another insulation system, it is necessary to carry out complex calculations, including thermal ones. In practice, when changing the insulation system due to thermal constraints, it may be necessary to reduce the rated total power of the turbine generator for its further operation without overheating of the stator winding, which can be obtained on the basis of simulation. The equivalent coefficient of thermal conductivity, which can be preliminarily analyzed to select the necessary materials for thermal properties and their fill factor to maintain the nominal parameters of the turbine generator during rewinding, is very important for the calculation, as it allows you to optimize the model settings and the computation time.