Efficient Rotordynamic Analysis Using the Superelement Approach for an Aircraft Engine

2017 ◽  
Author(s):  
Devesh Kumar ◽  
Konrad Juethner ◽  
Yves Fournier
Keyword(s):  
High Performance ◽  
Computational Cost ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Detailed Comparison ◽  
Model Description ◽  
High Fidelity ◽  
Large Engine ◽  
Shell Elements ◽  
Reduction Techniques

The exploration of new aero-engine configurations drives unseen and complex dynamic behavior which can only be captured accurately with enhanced modeling techniques. In an earlier publication, it was established that it is possible to analyze large engine models using high-fidelity two-dimensional (2D) axisymmetric harmonic and three-dimensional (3D) shell and solid elements. This finding stands in contrast to the relatively crude one-dimensional (1D) model simplifications that were introduced several decades ago. While motivated by limited computing power and easily obtained gyroscopic terms, these models are still common in the industry today. In spite of staggering advances in computation, however, said enhanced finite element rotor models are still considered to be quite large. When transitioning from the traditional 1D to the fully 3D rotor model, for example, one encounters an increase in model size of three orders of magnitude. This motivates the use of model reduction techniques such as the External Superelement (SE) which is obtained by component mode synthesis (CMS). The External SE represents a structural component by its physical attachment points, strategically selected interior grid points, and a linear combination of its dynamic modes. Its advantages are reduced computational cost, the ability to solve very large problems, the protection of intellectual property, and the enablement of a modular model description that promotes parallel processing as well as the utilization of high performance computing (HPC). In this paper, the analysis of a realistic aircraft engine is presented in which its rotating structures are modeled with high-fidelity 3D solid/shell elements. The dynamics of the engine assembly are solved using modal analysis and External SE technology with the goals to reduce wall time and improve efficiency. A detailed comparison of wall time is presented to quantify the associated performance gain.

GPU-Enabled High-Fidelity LES Simulations for Turbomachinery Flows

2021 ◽  
Author(s):  
Michal Osusky ◽  
Rathakrishnan Bhaskaran ◽  
Dheeraj Kapilavai ◽  
Greg Sluyter ◽  
Sriram Shankaran
Keyword(s):  
High Pressure ◽  
Engineering Design ◽  
Large Scale ◽  
Computational Cost ◽  
Three Dimensional ◽  
High Fidelity ◽  
High Pressure Turbine ◽  
Large Engine ◽  
Design Cycle ◽  
High Fidelity Simulations

Abstract Engineers performing computational simulations of flow physics are often faced with a trade-off between turn-around time and accuracy. High-fidelity models that can accurately capture small details of flow, such as turbulent mixing, are typically too expensive and are therefore reserved for studying smaller, component level problems. Standard models, like Reynolds-Averaged Navier-Stokes (RANS) and Unsteady-RANS, are used to predict larger interactions without the ability to accurately compute the small scales, at a lower computational cost than high-fidelity models. However, with specific algorithmic choices and access to large-scale GPU systems, we can demonstrate high-fidelity simulations of large engine sections that can be completed within engineering design cycle turn-around times, instead of the typical weeks to months required for high fidelity simulations. In this paper we present the high-order GENESIS code, employed in the simulation of complex turbulent flows inside the high-pressure turbine of a jet engine. The code efficiently exploits GPU accelerators to execute high-fidelity simulations, while also demonstrating extraordinary accuracy validated by experimental data and previous RANS model predictions. This is demonstrated for a three-dimensional high-pressure turbine stator domain, for which the LES is able to accurately predict wake mixing and temperature distribution, factors that are critical for designing durable turbine components. The new capability allows for computational studies of phenomena such as laminar to turbulent transition and wake mixing, all applied to relevant three-dimensional geometries present in the high-pressure turbine, all within the time scale of a typical engineering design cycle.

scholarly journals Prediction of Residual Stresses in a Multipass Pipe Weld by a Novel 3D Finite Element Approach

2018 ◽  
Author(s):  
Hui Huang ◽  
Jian Chen ◽  
Blair Carlson ◽  
Hui-Ping Wang ◽  
Paul Crooker ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
High Performance ◽  
Large Scale ◽  
Graphics Processing Unit ◽  
Computational Cost ◽  
Three Dimensional ◽  
Processing Unit ◽  
Girth Welds ◽  
Welding Processes

Due to enormous computation cost, current residual stress simulation of multipass girth welds are mostly performed using two-dimensional (2D) axisymmetric models. The 2D model can only provide limited estimation on the residual stresses by assuming its axisymmetric distribution. In this study, a highly efficient thermal-mechanical finite element code for three dimensional (3D) model has been developed based on high performance Graphics Processing Unit (GPU) computers. Our code is further accelerated by considering the unique physics associated with welding processes that are characterized by steep temperature gradient and a moving arc heat source. It is capable of modeling large-scale welding problems that cannot be easily handled by the existing commercial simulation tools. To demonstrate the accuracy and efficiency, our code was compared with a commercial software by simulating a 3D multi-pass girth weld model with over 1 million elements. Our code achieved comparable solution accuracy with respect to the commercial one but with over 100 times saving on computational cost. Moreover, the three-dimensional analysis demonstrated more realistic stress distribution that is not axisymmetric in hoop direction.

High-Fidelity AeroAcoustic Optimization Tool for Flexible Rotors

2020 ◽  
Author(s):  
Li Wang ◽  
Boris Diskin ◽  
Leonard V. Lopes ◽  
Eric J. Nielsen ◽  
Elizabeth Lee-Rausch ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Complex Variable ◽  
High Performance ◽  
Computational Cost ◽  
Geometric Constraints ◽  
General Level ◽  
High Fidelity ◽  
Variable Approach ◽  
Multidisciplinary Analysis ◽  
Tightly Coupled

A high-fidelity multidisciplinary analysis and gradient-based optimization tool for rotorcraft aero-acoustics is presented. Tightly coupled discipline models include physics-based computational fluid dynamics, rotorcraft comprehensive analysis, and noise prediction and propagation. A discretely consistent adjoint methodology accounts for sensitivities of unsteady flows and unstructured, dynamically deforming, overset grids. The sensitivities of structural responses to blade aerodynamic loads are computed using a complex-variable approach. Sensitivities of acoustic metrics are computed by chain-rule differentiation. Interfaces are developed for interactions between the discipline models for rotorcraft aeroacoustic analysis and the integrated sensitivity analysis. The multidisciplinary sensitivity analysis is verified through a complex-variable approach. To verify functionality of the multidisciplinary analysis and optimization tool, an optimization problem for a 40% Mach-scaled HART-II rotor-and-fuselage configuration is crafted with the objective of reducing thickness noise subject to aerodynamic and geometric constraints. The optimized configuration achieves a noticeable noise reduction, satisfies all required constraints, and produces thinner blades as expected. Computational cost of the optimization cycle is assessed in a high-performance computing environment and found to be acceptable for design of rotorcraft in general level-flight conditions.

Hierarchical Multiscale Modeling of Tire–Soil Interaction for Off-Road Mobility Simulation

2019 ◽  
Vol 14 (6) ◽  
Author(s):  
Hiroki Yamashita ◽  
Guanchu Chen ◽  
Yeefeng Ruan ◽  
Paramsothy Jayakumar ◽  
Hiroyuki Sugiyama
Keyword(s):  
High Performance ◽  
Computational Models ◽  
Computational Cost ◽  
Interaction Model ◽  
High Fidelity ◽  
Wheel Load ◽  
Mobility Performance ◽  
Wide Range ◽  
Computationally Intensive ◽  
Soil Bin

A high-fidelity computational terrain dynamics model plays a crucial role in accurate vehicle mobility performance prediction under various maneuvering scenarios on deformable terrain. Although many computational models have been proposed using either finite element (FE) or discrete element (DE) approaches, phenomenological constitutive assumptions in FE soil models make the modeling of complex granular terrain behavior very difficult and DE soil models are computationally intensive, especially when considering a wide range of terrain. To address the limitations of existing deformable terrain models, this paper presents a hierarchical FE–DE multiscale tire–soil interaction simulation capability that can be integrated in the monolithic multibody dynamics solver for high-fidelity off-road mobility simulation using high-performance computing (HPC) techniques. It is demonstrated that computational cost is substantially lowered by the multiscale soil model as compared to the corresponding pure DE model while maintaining the solution accuracy. The multiscale tire–soil interaction model is validated against the soil bin mobility test data under various wheel load and tire inflation pressure conditions, thereby demonstrating the potential of the proposed method for resolving challenging vehicle-terrain interaction problems.

scholarly journals A flash-based thermal simulation of scanning paths in LPBF additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kamel Ettaieb ◽  
Sylvain Lavernhe ◽  
Christophe Tournier
Keyword(s):  
High Performance ◽  
Laser Scanning ◽  
Thermal Field ◽  
Computational Cost ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Content Type ◽  
Proposed Model ◽  
Scanning Path

Purpose This paper aims to propose an analytical thermal three-dimensional model that allows an efficient evaluation of the thermal effect of the laser-scanning path. During manufacturing by laser powder bed fusion (LPBF), the laser-scanning path influences the thermo-mechanical behavior of parts. Therefore, it is necessary to validate the path generation considering the thermal behavior induced by this process to improve the quality of parts. Design/methodology/approach The proposed model, based on the effect of successive thermal flashes along the scanning path, is calibrated and validated by comparison with thermal results obtained by FEM software and experimental measurements. A numerical investigation is performed to compare different scanning path strategies on the Ti6Al4V material with different stimulation parameters. Findings The simulation results confirm the effectiveness of the approach to simulate the thermal field to validate the scanning strategy. It suggests a change in the scale of simulation thanks to high-performance computing resources. Originality/value The flash-based approach is designed to ensure the quality of the simulated thermal field while minimizing the computational cost.

The structure of self-sustained instability, transition and turbulence in the separating boundary layer under an internal solitary wave of depression

2021 ◽  
Author(s):  
Peter Diamessis ◽  
Takahiro Sakai ◽  
Gustaaf Jacobs
Keyword(s):  
Boundary Layer ◽  
Large Amplitude ◽  
High Performance ◽  
Separation Bubble ◽  
Computational Cost ◽  
Three Dimensional ◽  
Instability Mode ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Performance Computing

<p>The development of the separated bottom boundary layer (BBL) in the footprint of a large-amplitude ISW of depression is examined using high-accuracy/resolution implicit Large Eddy Simulation. The talk will focus on a single relatively idealized case of a large-amplitude ISW propagating against an oncoming barotropic current with its own, initially laminar, BBL under the inevitable restriction of laboratory-scale Reynolds number. Significant discussion will be dedicated to the non-trivial computational cost of setting up and conducting the above simulation, within long domains and over long-integration times, in a high-performance-computing environment. Results will focus on documenting the full downstream evolution of the structure of the separated BBL development. Particular emphasis will be placed on the existence of a three-dimensional global instability mode, at the core of the separation bubble where typically one might assume two-dimensional dynamics. The particular instability mode is spontaneously excited and is considered responsible for the self-sustained nature of the resulting near-bed turbulent wake in the lee of the ISW. Fundamental mean BBL flow metrics will then be presented along with a short discussion for potential for particulate resuspension. The talk will close with a discussion of the relevance of the existing flow configuration to both the laboratory and ocean, in light of recent measurements in the NW Australian Shelf.<br><br></p>

scholarly journals Avaliação de Desempenho no Supercomputador SDumont de uma Estratégia de Decomposição de Domínio usando as Funcionalidades de Mapeamento Topológico do MPI para um Método Numérico de Escoamento de Fluidos.

2020 ◽  
Author(s):  
Stiw Herrera ◽  
Weber Ribeiro ◽  
Thiago Teixeira ◽  
André Carneiro ◽  
Frederico Cabral ◽  
...  
Keyword(s):  
Domain Decomposition ◽  
Message Passing ◽  
High Performance ◽  
Message Passing Interface ◽  
Oil And Gas ◽  
Computational Cost ◽  
Three Dimensional ◽  
Data Allocation ◽  
Performance Study ◽  
Decomposition Strategies

Oil and gas simulations need new high-performance computing techniques to deal with the large amount of data allocation and the high computational cost that we obtain from the numerical method. The domain decomposition technique (domain division technique) was applied to a three-dimensional oil reservoir, where the MPI (Message Passing Interface) allowed the creation of a uni, bi and three-dimensional topology, where a subdivision of a reservoir could be solved in each MPI process created. A performance study was developed with these domain decomposition strategies in 20 computational nodes of the SDumont Supercomputer, using a Cascade Lake architecture.

High Performance Condition Monitoring of Aircraft Engines

2005 ◽  
Author(s):  
James P. Herzog ◽  
Jason Hanlin ◽  
Stephan W. Wegerich ◽  
Alan D. Wilks
Keyword(s):  
Real Time ◽  
Condition Monitoring ◽  
High Performance ◽  
Cost Savings ◽  
Aircraft Engine ◽  
Nonparametric Model ◽  
Normal System ◽  
High Fidelity ◽  
Aircraft Engines ◽  
Secondary Damage

A similarity-based modeling (SBM) technique is demonstrated that provides very early annunciation of the onset of gas path faults in aircraft engines. This powerful approach is shown to provide high fidelity estimates for real-time condition monitoring of aircraft engine signals. These estimates are used to detect the onset of changes in the inter-relationship between the various signals using a sophisticated set of built-in algorithms and tools. The ability of the SBM software to reliably detect subtle changes in signal behavior that are characteristic of a developing anomaly is coupled with a diagnostic rules engine to enable a rapid and robust fault recognition capability. The SBM software operates using a set of algorithms that construct a multivariate nonparametric model of the traditional monitoring sensors (pressure transducers, thermocouples, flow meters, etc.) present in the system. This model is used to generate real-time estimates of sensor values that represent normal system operation. A series of sophisticated tools compares these very high fidelity estimates to the actual sensor readings to detect discrepancies. Finally, a series of logic rules derived from a combination of engineering analysis and experience is applied to the output from the modeling engine in real-time to alert the user of developing serious conditions that need either immediate or planned maintenance attention. The software system provides a complete approach to asset monitoring that minimizes down time, maximizes availability, encodes (preserves) operator knowledge and lowers the overall costs associated with maintaining the assets. In this paper, we demonstrate the use of the similarity-based modeling approach for detecting faults in the gas path of aircraft engines. Some results from the monitoring of over 1,100 engines at a major commercial airline over a two-year period are described. Operationally, the early detection of developing engine faults has prevented delays and cancellations, and has contributed to a reduction in the airline’s in-flight shutdown rate. Financially, this approach has led to significant cost savings by the prevention of major secondary damage.

Recent Developments in High-Performance Computational Vibro-Acoustics in the Medium Frequency Regime

2012 ◽  
Author(s):  
Charbel Farhat ◽  
Radek Tezaur ◽  
Ulrich Hetmaniuk
Keyword(s):  
High Performance ◽  
Computational Cost ◽  
Medium Frequency ◽  
Time Frequency ◽  
Additional Information ◽  
Reduction Techniques ◽  
Discontinuous Enrichment ◽  
Recent Developments ◽  
Frequency Regime ◽  
Frequency Sweeps

Structural acoustics applications in the medium frequency regime are computationally challenging. One avenue of research pursues higher-order discretization methods that can deliver both accuracy and computational efficiency at smaller mesh resolutions. The Discontinuous Enrichment Method (DEM) is one example which distinguishes itself from competing approaches in the additional information it incorporates in the approximation method. It has shown a significant promise for acoustic and structural acoustic applications and therefore is reviewed here, together with new applications to shell problems. Frequency sweeps, which are almost inevitable in many vibro-acoustic engineering problems, present an additional challenge as they significantly increase the already high computational cost. Therefore, interpolatory model reduction techniques that successfully address this challenge and enable real-time frequency sweep analyses are also discussed in this paper.

scholarly journals Model Order Reduction in Computational Multiscale Fracture Mechanics

2016 ◽  
Vol 713 ◽  
pp. 248-253
Author(s):  
M. Caicedo ◽  
J. Oliver ◽  
A.E. Huespe ◽  
O. Lloberas-Valls
Keyword(s):  
Model Order Reduction ◽  
High Performance ◽  
Computational Cost ◽  
Order Reduction ◽  
Cementitious Materials ◽  
Reduced Model ◽  
Computational Time ◽  
Strong Discontinuity ◽  
Model Order ◽  
Reduction Techniques

Nowadays, the model order reduction techniques have become an intensive research eld because of the increasing interest in the computational modeling of complex phenomena in multi-physic problems, and its conse- quent increment in high-computing demanding processes; it is well known that the availability of high-performance computing capacity is, in most of cases limited, therefore, the model order reduction becomes a novelty tool to overcome this paradigm, that represents an immediately challenge in our research community. In computational multiscale modeling for instance, in order to study the interaction between components, a di erent numerical model has to be solved in each scale, this feature increases radically the computational cost. We present a reduced model based on a multi-scale framework for numerical modeling of the structural failure of heterogeneous quasi-brittle materials using the Strong Discontinuity Approach (CSD). The model is assessed by application to cementitious materials. The Proper Orthogonal Decomposition (POD) and the Reduced Order Integration Cubature are the pro- posed techniques to develop the reduced model, these two techniques work together to reduce both, the complexity and computational time of the high-delity model, in our case the FE2 standard model

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