Berechnung mehrstufiger Turbinen mit transsonischen Beschaufelungen unter Beruecksichtigung hoher Kuehlluftraten Abschlussbericht

The method presented here is a quasi-3-d through-flow scheme which reduces the three-dimensional flow problem to several two-dimensional calculations by introducing appropriate flow surfaces. In the case of machinery with subsonic through-flow the flow field for S_1 and _2_m flow surfaces is solved by means of a two-dimensional flow function approach. The method is coupled with a hyperbolic time-stepping approach on S_1 surfaces for the simulation of transonic flows. The combination of the inviscid time-stepping scheme on S_1 surfaces and the flow function approach on S_2_m''surfaces formulated with friction terms permits a quick calculation of turbomachinery components with transonic through-flow, while taking into account any losses. The switch-over of the difference scheme during the transition from subsonic flow to supersonic flow on S_2_m surfaces is controlled by integration of the velocity gradient equation and via numerical dissipation by means of an artificial density. To allow for cooling air mixing effects, the Q3D method was extended by a model which is capable of taking into account the cooling air mixing effects within turbines. The friction, gap flow and secondary flow losses are taken into account by means of empirical correlations within the Q3D method. (orig.)Available from TIB Hannover: F96B1088+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman