Implementation and Validation of a FEM Through-Flow Program Computing the Meridional Flow in Axial Turbines

Abstract

The turbine department of the DLR Institute of Propulsion Technology will use a through-flow program, which is based on a classical through-flow method using a stream function approach and a finite element solution procedure And it can be applied to calculate axisymmetric flow fields and predict the performance of axial gas turbines at subsonic conditions. In this diploma thesis, the program was thoroughly analyzed in three areas: the aerodynamic model, the numerical methods and the loss models. Based on the algorithm of the old program, the program was rewritten in FORTRAN 95 using advanced programming techniques. To test the new program, calculations were carried out for two turbines: a single-stage and a 4-stage experimental air turbine. The results of the flow field calculations were presented. The turbine overall performance was predicted, as well as for partial load. The new implementation of the program was validated by comparing the results with experimental measurement data and the results of the old FEMT program. In comparison with the old program, accuracy of the results were optimized and improved.