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.

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.

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.

Aerodynamic and Aeroacoustic Optimization of a Transonic Centrifugal Compressor

2014 ◽  
Author(s):  
Peng Wang ◽  
Mehrdad Zangeneh
Keyword(s):  
Pressure Ratio ◽  
Transonic Compressor ◽  
Numerical Predictions ◽  
Ansys Cfx ◽  
Transonic Centrifugal Compressor ◽  
Blade Tip ◽  
Surface Scheme ◽  
Lower Noise ◽  
Integral Surface ◽  
Good Agreement

The performance of transonic compressors can be characterized aerodynamically and aeroacoustically. In this paper, the DLR SRV2 compressor without vaned diffusers and its redesigned version are studied. The redesign strategy (Zangeneh et al. 2011 [1]) utilized the 3D inverse design and CFD analysis. Both compressors were analyzed in ANSYS CFX 11, and the computational results show that the predicted pressure-ratio and efficiency of the original compressor have good agreement with experimental results. The simulations have also revealed that the redesigned one is superior at both design and off-design points at different rotating speeds. This work applies a convective FW-H method to further investigate the noise radiation from these two compressors. As the blade tip speed is supersonic, the permeable integral surface scheme must be adopted. The flow quantities needed as the inputs to the FW-H solver were extracted from the CFD solutions. The numerical predictions of the noise SPLs at blade passing frequency and its harmonics match the experimental measurements reasonably well. It is found that the original compressor has significant variations of SPLs as the operating mass flow rate changes whereas the redesigned one has much slighter variations. At peak efficiency the redesigned compressor has a lower noise level. This study provides insights for the optimal design of a transonic compressor when good aerodynamic and aeroacoustic performance are both required.

Numerical Simulation of Single Thruster in Open Water

2017 ◽  
Author(s):  
Qin Zhang ◽  
Peifeng Ma ◽  
Jing Liu ◽  
Rajeev Kumar Jaiman
Keyword(s):  
Numerical Data ◽  
Open Water ◽  
Wake Flow ◽  
Dynamic Positioning ◽  
Floating Structure ◽  
Structured Grid ◽  
Rotating Blade ◽  
Blade Tip ◽  
Steady State Simulation ◽  
Good Agreement

The flow interaction between a dynamic positioning (DP) thruster and a floating structure (semi-submersible) hull attracted quite a lot of attention in recent years. In this study, the Spalart-Allmaras RANS model has been evaluated to simulate single thruster rotated in the open water with OpenFOAM. The actual thruster geometry has been meshed with structured grid, and the gap between the blade tip and nozzle is carefully treated. The Moving Reference Frame (MRF) method is used for steady-state simulation, and the arbitrary mesh interface (AMI) method is applied to simulate the rotating blade for transient dynamic mesh simulation. The numerical results are compared with available experimental and numerical data, especially in the wake flow. Good agreement is shown in this study.

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.

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.

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.

Numerical and Experimental Investigations on Preload Effects in Air Foil Journal Bearings

2017 ◽  
Author(s):  
Marcel Mahner ◽  
Pu Li ◽  
Andreas Lehn ◽  
Bernhard Schweizer
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Compressible Fluids ◽  
Experimental Investigations ◽  
Hysteresis Curves ◽  
Numerical Predictions ◽  
Bearing Stiffness ◽  
Gasdynamic Model ◽  
Good Agreement

A detailed elasto-gasdynamic model of a preloaded three-pad air foil journal bearing is presented. Bump and top foil deflections are herein calculated with a nonlinear beamshell theory according to Reissner. The 2D pressure distribution in each bearing pad is described by the Reynolds equation for compressible fluids. With this model, the influence of the assembly preload on the static bearing hysteresis as well as on the aerodynamic bearing performance is investigated. For the purpose of model validation, the predicted hysteresis curves are compared with measured curves. The numerically predicted and the measured hysteresis curves show a good agreement. The numerical predictions exhibit that the assembly preload increases the bearing stiffness (in particular for moderate shaft displacements) and the bearing damping.

Effects of Guide Vanes on the Tip Heat Transfer Enhancement of a Turbine Blade

2011 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Enhancement ◽  
Turbine Blade ◽  
Pressure Loss ◽  
Transfer Enhancement ◽  
Guide Vanes ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Blade Tip

Gas turbine blade tips encounter large heat load as they are exposed to the high temperature gas. A common way to cool the blade and its tip is to design serpentine passages with 180-deg turns under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase the blade tip life time. This paper presents numerical predictions of turbulent fluid flow and heat transfer through two-pass channels with and without guide vanes placed in the turn regions using RANS turbulence modeling. The effects of adding guide vanes on the tip-wall heat transfer enhancement and the channel pressure loss were analyzed. The guide vanes have a height identical to that of the channel. The inlet Reynolds numbers are ranging from 100,000 to 600,000. The detailed three-dimensional fluid flow and heat transfer over the tip-walls are presented. The overall performances of several two-pass channels are also evaluated and compared. It is found that the tip heat transfer coefficients of the channels with guide vanes are 10∼60% higher than that of a channel without guide vanes, while the pressure loss might be reduced when the guide vanes are properly designed and located, otherwise the pressure loss is expected to be increased severely. It is suggested that the usage of proper guide vanes is a suitable way to augment the blade tip heat transfer and improve the flow structure, but is not the most effective way compared to the augmentation by surface modifications imposed on the tip-wall directly.

On the Effect of Hull Girder Flexibility on the Vertical Wave Bending Moment for Ultra Large Container Vessels

2012 ◽  
Author(s):  
Ingrid Marie Vincent Andersen ◽  
Jørgen Juncher Jensen
Keyword(s):  
Bending Moment ◽  
Main Concern ◽  
Hull Girder ◽  
Numerical Predictions ◽  
Strip Theory ◽  
Reliability Method ◽  
Non Linear ◽  
Large Container ◽  
The Waves ◽  
Good Agreement

Currently, a number of very large container ships are being built and more are on order, and some concerns have been expressed about the importance of the reduced hull girder stiffness to the wave-induced loads. The main concern is related to the fatigue life, but also a possible increase in the global hull girder loads as consequence of the increased hull flexibility must be considered. This is especially so as the rules of the classification societies do not explicitly account for the effect of hull flexibility on the global loads. In the present paper an analysis has been carried out for the 9,400 TEU container ship used as case-ship in the EU project TULCS (Tools for Ultra Large Container Ships). A non-linear time-domain strip theory is used for the hydrodynamic analysis of the vertical bending moment amidships in sagging and hogging conditions for a flexible and a rigid modelling of the ship. The theory takes into account non-linear radiation forces (memory effects) through the use of a set of higher order differential equations. The non-linear hydrostatic restoring forces and non-linear Froude-Krylov forces are determined accurately at the instantaneous position of the ship in the waves. Slamming forces are determined by a standard momentum formulation. The hull flexibility is modelled as a non-prismatic Timoshenko beam. Generally, good agreement with experimental results and more accurate numerical predictions has previously been obtained in a number of studies. The statistical analysis is done using the First Order Reliability Method (FORM) supplemented with Monte Carlo simulations. Furthermore, strip-theory calculations are compared to model tests in regular waves of different wave lengths using a segmented, flexible model of the case-ship and good agreement is obtained for the longest of the waves. For the shorter waves the agreement is less good. The discrepancy in the amplitudes of the bending moment can most probably be explained by an underestimation on the effect of momentum slamming in the strip-theory applied.

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