This thesis deals with the modelling of two-dimensional coupling of quasi one-dimensional domains and turbulence within a quasi one-dimensional combustion chamber. Also an interpolation-free finite volume moving mesh method is described.
First, the basic framework of a gas turbine is introduced including an uncommon approach for constant volume combustion: the shockless explosion combustion (SEC). In a preceding work a simulation code for this combustion process solving quasi one-dimensional reactive Euler equations with a finite volume (FV) Riemann solver has been developed and was extended for the thesis at hand.
A network model is presented, allowing for the investigation of interaction of multiple pulsating combustion chambers of an SEC gas turbine with the plenums and each other. It couples the quasi one-dimensional domains using boundary conditions and flux corrections such that interactions of slanted combustion chambers with the plenums are possible. A series of simulations utilising this model is carried out to show possible fields of research for this tool.
As the simulation of combustion processes are especially sensitive to spacial resolution but complex chemistry also imposes restrictions on the number of grid cells a feature for adaptive remeshing is described. It uses the moving mesh idea within the FV solver. As interpolation introduces too much numerical diffusion a flux correction is given which evolves governing equations and mesh simultaneously without changing the Euler equations themselves. The performance of this feature is demonstrated with simulations of a detonation and a cyclic SEC.
Finally, the prerequisites for the research of the starting process of an SEC gas turbine are created by including molecular transport and turbulence in the SEC-code. Towards this aim, the one-dimensional turbulence (ODT) model is adjusted for this application. The ODT-line on which the stochastic eddy events, representing the turbulence, occur is aligned with the streamwise direction of the long-stretched combustion chamber. Also ODT is used as a stand-alone and subgrid-scale model. The main features of turbulence and ODT are compared to the new variant ODT-FHD. This study reveals that the ODT-FHD is able to generally reproduce the correct dependency of turbulence on mean flow velocity along with a plausible distribution of eddy sizes and kinetic energies. While lacking the possibility to generate new extrema of flow properties along the ODT-line it incorporates turbulent diffusion very well. The influence of the three model parameter is shown in addition to the simulation of a turbulent flame and a turbulent single-tube SEC.
