Towards the Large-Eddy Simulation of a full engine: Integration of a 360 azimuthal degrees fan, compressor and combustion chamber. Part II: Comparison against stand-alone simulations

Abstract

Unsteady simulations of various components of a gas-turbine engine are often carried out independently and only share averaged quantities at the component interfaces. In order to study the impact and interactions between components, this work compares results from sectoral stand-alone simulations of a fan, compressor and annular combustion chamber of the DGEN-380 demonstrator engine at take-off conditions against an integrated 360 azimuthal degrees large-eddy simulation with over 2.1 billion cells of all previously listed components. Note that, at take-off conditions the compressor works at transonic conditions and generates an upstream-propagating shock that interacts with the fan modifying the shape of its wake with respect to the stand-alone simulation. Furthermore, the shock is seen as a tone in the pressure spectra at half the impeller blade passing frequency in the forward region of the engine. In the aft region, time-averaged fields are overall similar between stand-alone and integrated simulations but show a deviation in the azimuthal position of the hot-spot at the exit of the combustion chamber due to the addition of the diffuser. Pressure fluctuations generated in the compressor are captured in the combustion chamber as tones in the temperature and pressure spectra at the impeller blade-passing frequency and harmonics as well as an increase in the root-mean-square pressure.

A Performance Simulation Methodology for a Whole Turboshaft Engine Based on Throughflow Modelling

“…The fuel flow and speed are given as input parameters according to the experimental data. Arroyo et al [11,12] employed Large Eddy Simulation (LES) methods to perform multi-component coupled simulations on a gas turbine with 360 azimuthal degrees, comprising over 2.1 billion grid cells, including the fan, radial compressor, and annular combustion chamber. The project obtained 31.6 million core hours of supercomputing resources to accomplish these computations through the Partnership for Advanced Computing in Europe (PRACE).…”

Generation of Realistic Boundary Conditions at the Combustion Chamber/Turbine Interface Using Large-Eddy Simulation

“…Thus, to be able to accurately simulate the multicomponent coupling without reducing the number of blades or without additional simplifying assumptions, the best option is to perform a 360 • simulation of the complete turbomachine. Despite the constant progress in computing capabilities, very few examples of complete engine simulations are available in the literature (even fewer using LES) and in any case, these simulations remain very expensive [1][2][3][4]. As a re-Energies 2021, 14, 8206 2 of 23 sult, and for engine manufacturers, this solution is not feasible today during the design phases, and other options must be considered.…”