scholarly journals Full 3D Rotor/Stator Interaction Simulations in Aircraft Engines With Time-Dependent Angular Speed

2016 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Christophe Pierre
Keyword(s):  
Aircraft Engine ◽  
Angular Speed ◽  
Industrial Test ◽  
Numerical Results ◽  
Time Dependent ◽  
Abradable Coating ◽  
Acceleration And Deceleration ◽  
Rotor Stator Interaction ◽  
Nonlinear Nature ◽  
Numerical Strategy

Modern aircraft engine designs feature reduced clearances that may initiate structural contacts between rotating and static components. A numerical strategy dedicated to the simulation of such interactions is here enriched in order to account for time-dependent angular speeds. This contribution first details the evolution of the numerical strategy before validating the developments by comparing numerical results with experimental observations made on an industrial test bench. Further numerical investigations allow to assess the sensitivity of numerical results to acceleration and deceleration rates. Results, obtained with and without abradable coating, underline the fundamental nonlinear nature of the analysed system. It is found that lower acceleration rates favour the arisal of interaction phenomena and that amplitudes of vibration at a given angular speed are generally lower when the blade decelerates.

scholarly journals Full Three-Dimensional Rotor/Stator Interaction Simulations in Aircraft Engines With Time-Dependent Angular Speed

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Christophe Pierre
Keyword(s):  
Three Dimensional ◽  
Aircraft Engine ◽  
Angular Speed ◽  
Industrial Test ◽  
Numerical Results ◽  
Time Dependent ◽  
Abradable Coating ◽  
Acceleration And Deceleration ◽  
Rotor Stator Interaction ◽  
Numerical Strategy

Modern aircraft engine designs feature reduced clearances that may initiate structural contacts between rotating and static components. A numerical strategy dedicated to the simulation of such interactions is here enriched in order to account for time-dependent angular speeds. This contribution first details the evolution of the numerical strategy before validating the developments by comparing numerical results with experimental observations made on an industrial test bench. Further, numerical investigations allow to assess the sensitivity of the numerical results to acceleration and deceleration rates. The results, obtained with and without abradable coating, underline the fundamental nonlinear nature of the analyzed system. It is found that the lower acceleration rates favor the arisal of interaction phenomena, and that the amplitudes of vibration at a given angular speed are generally lower when the blade decelerates.

Implementation of a Rig Test for Rotor/Stator Interaction of Low-Pressure Compressor Blades and Comparison of Experimental Results With Numerical Model

2020 ◽  
Author(s):  
Laura Pacyna ◽  
Alexandre Bertret ◽  
Alain Derclaye ◽  
Luc Papeleux ◽  
Jean-Philippe Ponthot
Keyword(s):  
Low Cost ◽  
Low Pressure ◽  
Angular Speed ◽  
Compressor Blades ◽  
Abradable Coating ◽  
Rotor Stator Interaction ◽  
Blade Tip ◽  
Numerical Tool ◽  
Short Time ◽  
Pressure Compressor

Abstract To investigate the contact phenomenon between the blade tip and the abradable coated casing, a rig test was designed and built. This rig test fills the following constraints: simplification of the low-pressure compressor environment but realistic mechanical conditions, ability to test several designs in short time, at low cost and repeatability. The rig test gives the opportunity to investigate the behavior of different blade designs regarding the sought phenomenon, to refine and mature the phenomenon comprehension and to get data for the numerical tool validation. The numerical tool considers a 3D finite elements model of low-pressure compressor blades with a surrounding rigid casing combined with a specialized model to take into account the effects of the wear of the abradable coating on the blade dynamics. Numerical results are in good agreement with tests in terms of: critical angular speed, blade dynamics and wear pattern on the abradable coated casing.

scholarly journals Numerical Simulation of Tool/Abradable Material Interaction Experiments

2012 ◽  
Author(s):  
Alain Batailly ◽  
Marion Cuny ◽  
Mathias Legrand
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Rate Dependence ◽  
Strain Rate Dependence ◽  
Robust Solution ◽  
Abradable Coating ◽  
Rotor Stator Interaction ◽  
Material Interaction ◽  
Numerical Strategy

Applying abradable coating on the casing of turbomachines has been widely recognized as a robust solution advantageously combining the adjustment of operating clearances with the reduction of potential non-repairable damages. Thus, the modeling of this material is a growing field of investigation. Based on the numerical strategy proposed and detailed in previous publication by the same authors, the present study aims at capturing the mechanical behavior of abradable coating in the context of high speed interaction with a rigid tool. The plastic law given is first enriched in order to take into account strain rate dependence. The sensitivity of the model regarding its main numerical parameters is assessed and highlights the role of each of these parameters. The calibration of numerical results with respect to experimental results lead to very satisfying results that confirm that the proposed strategy is well-suited for the modeling of abradable coating. Finally, the newly developped viscoplastic law is applied to a 3D rotor/stator interaction case to determine the criticity of strain rate dependence in the case of blade/casing contact.

Experimental and Numerical Simulation of a Contact Induced Rotor/Stator Interaction Inside an Aircraft Engine High-Pressure Compressor

2016 ◽  
Author(s):  
Alain Batailly ◽  
Quentin Agrapart ◽  
Antoine Millecamps
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Aircraft Engine ◽  
Numerical Results ◽  
High Pressure Compressor ◽  
Short Period ◽  
Set Up ◽  
Pressure Compressor ◽  
Interaction Phenomena ◽  
Numerical Strategy

The development of a predictive numerical strategy for the simulation of rotor/stator interactions is a concern for several aircraft engine manufacturers. As a matter of fact, modern designs of aircraft engines feature reduced operating clearances between rotating and static components which yields more frequent structural contacts. Subsequent interaction phenomena (be it rubbing events, modal interaction or whirl motions) are not yet fully understood. For that reason, experimental data obtained from set-ups dedicated to the simulation of such interactions are scrutinized and are key in: (1) increasing the knowledge of the interaction phenomena and (2) allowing for a calibration of the numerical models with realistic events. In this contribution, the focus is made on an experimental set-up in Snecma facilities. It features a full-scale high-pressure compressor stage and aims at simulating contact induced interactions between one of the blades (slightly longer than the other ones) and the surrounding abradable coating that is deposited along the casing circumference. For this experimental set-up, it is found that the witnessed interaction involves a single blade — thus it should be analyzed as a sequence of rubbing events — and more specifically its first torsional mode, which is its second free-vibration mode. The focus is made both on the presentation of the experimental set-up and on the confrontation with the numerical results. Numerical results are analyzed by means of adaptative signal processing techniques and the consistency between numerical results and experimental observations is underlined both in time and frequency domains. In particular, the numerical strategy developed for Snecma is shown to predict very accurately the nature of the interaction as wear patterns obtained experimentally and numerically are a match. This numerical/experimental confrontation is the first attempt to calibrate a sophisticated numerical strategy with experimental data acquired within the high-pressure compressor of an aircraft engine for the simulation of rotor/stator interactions. Contrary to previous studies carried out within the low-pressure compressor of an aircraft engine, this interaction is found to be non-divergent: high amplitudes of vibration are experimentally observed and numerically predicted over a very short period of time. The ability of the numerical strategy to predict torsion induced interactions opens avenues for further analyses in turbine stages and with more sophisticated models including mistuned bladed disks and multi-stage components.

scholarly journals Numerical Study of a Rotor/Stator Interaction Case Experimentally Simulated With an Industrial Compressor

2012 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
Francois Garcin
Keyword(s):  
Numerical Study ◽  
Technical Solution ◽  
Blade Design ◽  
Rotating Blade ◽  
Abradable Coating ◽  
Rotor Stator Interaction ◽  
Blade Tip ◽  
The Impact ◽  
Good Agreement ◽  
Numerical Strategy

Higher aircraft energy efficiency may be achieved by minimizing the clearance between the rotating blade tips and respective surrounding casing. A common technical solution consists in the implementation of an abradable liner which improves both the operational safety and the efficiency of modern turbomachines. Recently, unexpected abradable wear removal mechanisms were observed in experimental set-ups and during maintenance procedures. The present study introduces a numerical strategy capable to address this occurrence. After focusing on the analysis of the experimental results, the good agreement between experimental observations and numerical results is illustrated in terms of critical stress levels within the blade as well as final wear profiles of the abradable liner. New blade designs are also explored in order to assess the impact of blade design on the outbreak of the interaction phenomenon. The prevalence of three dominant parameters in the interaction onset is shown: (1) blade design, (2) abradable material mechanical properties and (3) the need for a global distortion of the casing to synchronize blade-tip/abradable coating contacts.

scholarly journals Numerical-Experimental Comparison in the Simulation of Rotor/Stator Interaction Through Blade-Tip/Abradable Coating Contact

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
François Garcin
Keyword(s):  
Experimental Comparison ◽  
Technical Solution ◽  
Numerical Predictions ◽  
Rotating Blade ◽  
Abradable Coating ◽  
Highly Sensitive ◽  
Rotor Stator Interaction ◽  
Blade Tip ◽  
Good Agreement ◽  
Numerical Strategy

Higher aircraft energy efficiency may be achieved by minimizing the clearance between the rotating blade tips and respective surrounding casing. A common technical solution consists in the implementation of an abradable liner which improves both the operational safety and the efficiency of modern turbomachines. However, unexpected abradable wear removal mechanisms were recently observed in experimental set-ups as well as during maintenance procedures. Based on a numerical strategy previously developed, the present study introduces a numerical-experimental comparison of such occurrence. Attention is first paid to the review and analysis of existing experimental results. Good agreement with numerical predictions is then illustrated in terms of critical stress levels within the blade as well as final wear profiles of the abradable liner. Numerical results suggest an alteration of the abradable mechanical properties in order to explain the outbreak of a divergent interaction. New blade designs are also explored in this respect and it is found that the interaction phenomenon is highly sensitive to (1) the blade geometry, (2) the abradable material properties, and (3) the distortion of the casing.

THE TEMPERATURE DISTRIBUTION PRODUCED BY ACOUSTIC ABSORPTION: I. MACROSCOPIC TREATMENT

1966 ◽  
Vol 44 (12) ◽  
pp. 3001-3011 ◽  
Author(s):  
S. Simons
Keyword(s):  
Temperature Distribution ◽  
Acoustic Wave ◽  
Numerical Results ◽  
Time Dependent ◽  
Acoustic Absorption ◽  
Space And Time

A calculation is given of the temperature distribution in space and time produced by the absorption of an acoustic wave propagated inside a medium, under conditions in which the situation may be described macroscopically. The problem is considered for various geometries, and for both constant and time-dependent energies of the incident acoustic wave. Numerical results are obtained, and a discussion is given of their relevance to various experiments.

scholarly journals Conjectural Bifurcation Analysis of an Aircraft Engine Blade Undergoing 3D Unilateral Contact Constraints

2014 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand
Keyword(s):  
Spline Interpolation ◽  
Sudden Change ◽  
Aircraft Engine ◽  
Rotational Frequency ◽  
Compressor Blade ◽  
Structural Behaviour ◽  
Mode Decomposition ◽  
Abradable Coating ◽  
Set Up ◽  
Pressure Compressor

Prediction of rotor/stator interaction phenomena between a blade-tip and the surrounding abradable coating deposited on the casing has seen recent promising numerical developments that revealed consistency with several experimental set-up. In particular, the location of critical rotational frequencies, damaged blade areas as well as the wear pattern along the casing circumference were accurately predicted for an interaction scenario involving a low-pressure compressor blade and the surrounding abradable coating deposited on a perfectly rigid casing. The structural behaviour of the blade in the vicinity of a critical rotational frequency however remains unclear as brutal amplitude variations observed experimentally could not be numerically captured without assuming contact loss or an improbable drastic and sudden change of the abradable coating mechanical properties during the interaction. In this paper, attention is paid to the structural behaviour of a high-pressure compressor blade at the neighbourhood of a critical rotational frequency. The interaction scenarios for two close rotational frequencies: Ωc and Ωc* are analyzed using empirical mode decomposition based on an adjusted B-spline interpolation of the time responses. The obtained results are compared to the interaction scenario dictated by the abradable coating removal history and the location of contact areas. The unstable nature of the blade vibratory response when the rotational frequency exceeds a critical rotational frequency is underlined and a plausible scenario arises for explaining a sudden and significant decrease of the blade amplitude of vibration without contact separation.

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