Sealing systems in aircraft turbines offer significant optimization potential to minimize the clearance flow between blade tips and casing, enabling efficient and sustainable propulsion. Specifically, the sealing system is intended to ensure reliable abrasive cutting during inlet operation or friction contact, even during long service life. The Institute of Thermodynamics at the Universität der Bundeswher München is responsible for modeling the heat transfer process in the sealing system based on non-equilibrium thermodynamics. The modeling is implemented through the extended heat transfer theory and the finite element method to enable an analysis of the system. This enhances the understanding of unsteady heat transfer and allowing early detection of hot spots. Based on the extended heat transfer theory, the hyperbolic heat transfer equations by Cattaneo and Christov are presented, taking into account relative movements. Their differences from the parabolic Fourier equation are explained and highlighting their significance in both microscopic and macroscopic frame. The hyperbolic heat transport equation according to Christov-Cattaneo is discretised using the finite element method by Galerkin and is integrated over time with various numerical schemes. With the developed HypHeat2D program, it is possible to solve parabolic and hyperbolic planar 2-D heat transfer problems with large relative movements and systems with thermal Mach numbers Math = [0; 1] in non-equilibrium within a single equation system. In the conducted studies, it has been demonstrated that the hyperbolic heat transfer equation exhibits a more physical behavior compared to the parabolic equation, while showing larger temperature gradients and a thermal shock for Math = 1. In cases with relative velocities v > 0, antisymmetric temperature profiles with large gradients at the heat source front and the maximum temperature at the heat source backside emerge. Within the application cases, this results in an increased risk of temperature peaks in the sealing system and consequently high thermal stresses at the blade trailing edge and between the adhesive layer and the embedded particles. Furthermore, investigations on an RDE (rotating detonation engine) combustion chamber illustrate the differences between hyperbolic and parabolic heat conduction over unsteady temperature gradients, with the hyperbolic equation predicting a larger gradient.    «

Sealing systems in aircraft turbines offer significant optimization potential to minimize the clearance flow between blade tips and casing, enabling efficient and sustainable propulsion. Specifically, the sealing system is intended to ensure reliable abrasive cutting during inlet operation or friction contact, even during long service life. The Institute of Thermodynamics at the Universität der Bundeswher München is responsible for modeling the heat transfer process in the sealing system based o...    »