Finite element transient modelling for whole engine-secondary air system thermomechanical analysis

This paper presents a new procedure developed in cooperation with Ansaldo Energia and aimed to predict metal temperatures in a gas turbine whole engine with an axisymmetric transient finite element approach. The 2D model includes a dedicated thermal fluid network where mass flow rates and pressure distributions are provided by external fluid network solvers in terms of time serie, while fluid-metal temperatures are computed through a customized version of CalculiX®. This work represents a first insight about a fully integrated WEM (Whole Engine Modelling) procedure currently under development. The future implementation steps will be oriented to the usage of a customized version of the native CalculiX® fluid network solver and the implementation of a system of monitoring and updating of the secondary air system (SAS) geometry. The aim is to progress from the current partly coupled approach with previously assessed mass flow and pressure distributions, to a fully integrated procedure able to take into account the interaction between the SAS fluid properties and the modifications in the geometry caused by mechanical and thermal loads. In this paper, the methodology will be presented introducing some details about the main modelling aspects and illustrating some preliminary results from the test of the procedure applied to a simplified model representative of a real engine geometry under transient conditions.