Multi-Disciplinary Tool Coupling for the Determination of Turbofan Transients During Preliminary Design

Abstract

Over the past decades of preliminary aero-engine design a great effort has been invested in increasing steady-state efficiency to reduce missions fuel burn and thus CO2 emissions. Whilst pushing the performance cycle further to its limits previously minor deemed processes such as the transient behavior become more important because engines stability must still be granted for. It is therefore beneficial to integrate transient performance early into the overall aero-engine design tool chain to be able to predict the dynamic behavior from the beginning. This paper presents a methodology to couple predesign and transient performance simulation in order to get a more holistic picture of aero-engines early in the design process. This procedure entails extensive amount of data transfer throughout multi-disciplinary tools with different fidelity levels. This task is tackled using DLRs virtual engine platform GTlab (Gas Turbine Laboratory), which provides a geometric data model with abstract description of predesign components and standardized interfaces for data exchange. In order to demonstrate the proposed methodology a performance model of a turbofan similar to the V2500 aero-engine is used. For that purpose, a performance cycle is established providing boundary conditions for the preliminary aerodynamic engine design. The designed components provide necessary input data for the subsequent transient certification maneuver Eventually, parametric studies are conducted to show the impact of design variations on transient data such as the minimum surge margin and minimum tip clearance as well as on preliminary engine design.

Quasi-2d Thermal Network Based Heat Soakage Model for Gas Turbine Transient Performance Modification

“…It was found that the additional heat flow from the engine metal to the air led to an increase in the specific heat (Cp). The lumped parameter method (LPM) has been widely utilized for heat soakage analysis due to its convenience [9][10][11][12][13][14]. In the LPM, each component is assumed as a mass node at the centre of real component geometry.…”

“…Vieweg et al developed a heat soakage model based on LPM. They compared their results with experimental data and an improvement in model accuracy was found when compared with the model without considering the heat soakage effect [11,14]. However, improvements can be made to consider cooling technologies and heat conduction.…”

Novel Aero-Engine Multi-Disciplinary Preliminary Design Optimization Framework Accounting for Dynamic System Operation and Aircraft Mission Performance

“…Furthermore, the integration of control-system design and engine transient performance assessment as part of a multi-disciplinary preliminary design calculation has not been reported before in the public literature. Recent studies on novel propulsion systems have demonstrated the importance of considering transient performance as early as possible in the preliminary engine design phase in order to assess response and operability, but did not evaluate it as part of an overall cycle optimization at the aircraft-mission level [10] and with consideration of the design of the associated control system [11].…”

Axial Compressor Mean-Line Analysis: Choking Modelling and Fully-Coupled Integration in Engine Performance Simulations

“…During the early design stages, the need for fast and reliable multi-fidelity and multidisciplinary platforms (e.g., [2,3]), has made compressor mean-line (1D) models a valuable tool for the designer. They allow studying the effects of heat transfer [4], water evaporation, novel combustion concepts [5], and low-power operation on compressor aerodynamics [6].…”

“…• De-coupled: the higher fidelity code is used to generate compressor characteristics which are then used as data in the conventional 0D cycle code (e.g., [3]). • Semi-coupled: An iterative scheme is implemented, where the 0D cycle analysis provides boundary conditions to the 1D code and then the 0D component performance is updated according to the higher fidelity results.…”