Innovative Technologies for EIS Compressors after 2015

As developing modern aviation engines becomes more and more challenging with respect to reliability, degree of efficiency and weight, highly developed design tools are needed. These are connected with the quality of the design in an elementary way. Especially the increasing exploration and exploitation of technical boundaries and detailed designs let the demands on numerical simulation rise considerably.

[Bildunterschrift:] Figure: Transsonic airfoil RAE 2822 with heavy shock-boundary-layer-interaction: Improved prediction of the shock; Hellsten EARSM (H-EARSM) compared tot he Wilcox standard model. Left picture: Mach-number dispersion, right picture: Dispersion of the pressure coefficient.

Figure: Bent Wall: Improved prediction oft he decreasing turbulence with EARSM. Left picture: Grid and geometry, right picture: Dispersion of the friction coefficient on the convex wall.

Likewise the demands on aerodynamic design processes for compressor components are determined by precise prediction reliability of the entire compressor map. A precise prediction requires a detailed as possible reproduction of the geometry, as well as inclusion of all occurring flow phenomena. This includes the laminar-turbulent transition and the consideration of critical flow conditions in highly strained operating areas near to the pumping limit or at a low partial load. Under these conditions heavy separation occurs, which has to be depicted by numerical means as close to reality as possible. All process improvements are to deliver robust and reliable simulation results after short computing time, in order to be suited for applications in an industrial environment.

Figure: Comparison of the pressure distribution of the T160 turbine cascade at
50% channel height for the different mesh topologies

Aims for subproject TP1.2 referring to overall aims

The principal ambition of this project is the add-on of a three-dimensional simulation process based on the linearized and non-linearied Navier-Stokes equation for aeroelastic and aerodynamic compressor uses. By means of the expansion which is to be done in this project, the aerodynamic and aeroelastic prediction abilities of the existing numerical process for compressor designs is supposed to be vitally enhanced. A concrete aim is to reduce the running time of instationary compressor applications by at least one order after integrating the add-ons of this project. Furthermore the existing turbulence model is supposed to be expanded for highly detached flow effects in compressors, so as to achieve far better prediction qualities for critical operating areas. Besides, the linearized module for predicting Flutter & Forced-Response is to be expanded by turbulent entries.

Aims for work package AP2.1

Figure: Compressor grid with gap: A more precise depiction of the velocity deficiency in the center of the gap eddy. Left: descriptive view of the gap eddy, right: velocity dispersion in a level slice near the rear edge of theblade.

The principal aim of this work package is the add-on of a three-dimensional simulation process based on the linearized Navier-Stokes equations for aeroacoustic turbine applications. By means of this expansion the existing numerical process is supposed to be enabled to calculate the sonic spread of turbine components. The simulation process is based on the solution of the linearized Navier-Stokes equations. These linearized equations allow for very short computing times by neglecting certain frequency sections. Thus, after integrating these add-ons, a most efficient design method for predicting sonic emissions is supposed to be available