AUTOMATED CFD ANALYSIS WITHIN THE PRELIMINARY COMBUSTOR DESIGN SYSTEM PRECODES UTILIZING IMPROVED COOLING MODELS

摘要

The design of state-of-the-art combustion chambers is based on a multitude of design rules. To use this knowledge more effectively and to accelerate the combustor design process an automated combustion chamber design tool is being developed within the European project INTELLECT D.M. (Integrated Lean Low Emission Combustor Design Methodology). Due to the automation of the design process the time required to set up a new preliminary combustion chamber design is reduced from weeks to hours. The development of the automated preliminary combustor design tool is described in [1]. The focus of this paper is on new developments of the design system PRECODES (preliminary combustor design system) including automated mesh generation and CFD simulation.Design rules and parameters are formalized and stored within an EXCEL database. The combustor layout process including the calculations of cooling air mass flows and the zonal layout is done automatically using this database. The layout process has to be iteratively adjusted in order to find an optimal design due to the nonlinear interdependence of some of the design variables.The EXCEL database provides information for two para-metric CAD models. The first parametric model includes the flame tube, pre-dijfuser, cowl, metering panel, heatshield and the casing. Therefore it is relatively complex and only used for weight approximation and visualization purposes. The second CAD model is a generic model of the flame tube providing the basis for the automatic CFD mesh generation and CFD simulations. The CAD geometry is transferred to the commercial grid generator ICEM-CFD via the ICEM internal direct CAD interface. Based on the CAD geometry a multiblock structured mesh is generated automatically.Due to the utilization of the same blocking master model for different flame tubes varying in combustor size and orientation, and size and position of the mixing holes the mesh topology differs only marginally between different designs. Thus the CFD simulations are well comparable. Different combustor configurations are generated based on input parameter changes, I.e. changing the pressure level, the zonal stoichiometry or the maximum allowable material temperatures. An overview of the present results and the potentials of applying the automated combustor design tool PRECODES is presented.