scholarly journals Monte Carlo Predictions of Aero-Engine Performance Degradation Due to Particle Ingestion

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 146
Author(s):  
Matthew Ellis ◽  
Nicholas Bojdo ◽  
Antonio Filippone ◽  
Rory Clarkson
Keyword(s):  
High Pressure ◽  
Monte Carlo ◽  
Particle Deposition ◽  
Monte Carlo Model ◽  
Engine Performance ◽  
Performance Data ◽  
High Pressure Turbine ◽  
Particle Cloud ◽  
Validation Data ◽  
Particle Properties

Aero-engines, which encounter clouds of airborne particulate, experience reduced performance due to the deposition of particles on their high-pressure turbine nozzle guide vanes. The rate of this degradation depends on particle properties, engine operating state and the duration of exposure to the particle cloud, variables that are often unknown or poorly constrained, leading to uncertainty in model predictions. A novel method coupling one-dimensional gas turbine performance analysis with generalised predictions of particle deposition is developed and applied through the use of Monte Carlo simulations to better predict high-pressure turbine degradation. This enables a statistical analysis of deterioration from which mean performance losses and confidence intervals can be defined, allowing reductions in engine life and increased operational risk to be quantified. The method is demonstrated by replicating two particle cloud encounter events for the Rolls-Royce RB211-524C engine and is used to predict empirical particle properties by correlating measured engine performance data with Monte Carlo model inputs. Potential improvements in the confidence of these predictions due to more tightly constrained input and validation data are also demonstrated. Finally, the potential combination of the Monte Carlo coupled degradation model with in-service engine performance data and particle properties determined through remote or in situ sensing is outlined and its role in a digital twin to enable a predictive approach to operational capability is discussed.

Assessment of RANS Against LES for the Aero-Thermal Behavior of High Pressure Turbine Stages Under Realistic Inlet Conditions

2016 ◽  
Author(s):  
Stefano Vagnoli ◽  
Tom Verstraete ◽  
Charlie Koupper ◽  
Guillaume Bonneau
Keyword(s):  
High Pressure ◽  
Thermal Behavior ◽  
Turbulence Modeling ◽  
Engine Performance ◽  
High Pressure Turbine ◽  
Lean Burn ◽  
Field Development ◽  
Safety Margins ◽  
Inlet Conditions ◽  
Hot Streak

Modern Lean Burn combustors generate a complex field at the High Pressure turbine (HPT) inlet, characterized by non-uniform velocity and temperature distributions, together with very high turbulence levels (up to 25%). For these extreme conditions, classical numerical methods employed for the HPT design, such as Reynolds Averaged Navier Stokes (RANS) simulation, suffer from a lack of validation. This leads to a reduced confidence in predicting the combustor-turbine interactions, which requires to use extra safety margins, to the detriment of the overall engine performance. Within the European FACTOR project, a 360° non reactive combustor simulator and a 1.5 HPT stage are designed to get more insight into the mutual interaction of these two components. A first experimental and numerical campaign has demonstrated the potential of Large Eddy Simulations (LES) to accurately reproduce the turbulent flow field development at the combustor outlet. The aim of the present paper is to exploit the accuracy of LES to validate less time-consuming RANS models in predicting the hot streak migration in the turbine stage. In this sense, LES results are used as a reference to discriminate the different RANS simulations in terms of turbulence modeling and aerothermal predictions. The current investigations clearly indicate that turbulence and hot streak diffusion within the HPT are strongly linked. In this sense, the choice of the RANS turbulence model and the inlet turbulent conditions plays a major role in modeling the thermal behavior for the stator and rotor blades.

Photon Monte Carlo Model for High-Pressure Reacting Laminar Flows

2012 ◽  
Author(s):  
Shenghui Lei ◽  
Jian Cai ◽  
Adhiraj Dasgupta ◽  
Michael F. Modest ◽  
Daniel Haworth
Keyword(s):  
High Pressure ◽  
Monte Carlo ◽  
Spectral Line ◽  
Monte Carlo Model ◽  
Laminar Flows ◽  
Present Problem ◽  
Elevated Pressures

In this paper, laminar H2-air flames at elevated pressures up to 10 bar are numerically studied. To capture the influence of radiation on high-pressure flames, a photon Monte Carlo (PMC) scheme combined with a spectral line-by-line (LBL) method previously developed by the authors is employed. In the present problem, the only radiating species is H2O. The importance of radiation in high-pressure flames is demonstrated by comparing differences of temperature and concentration fields for the cases with and without radiation.

Predicting the Temporal Progression of Aircraft Engine Compressor Performance Deterioration due to Particle Deposition

2017 ◽  
Author(s):  
Felix Döring ◽  
Stephan Staudacher ◽  
Christian Koch
Keyword(s):  
High Pressure ◽  
Particle Deposition ◽  
Operating Time ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Operating Costs ◽  
Maximum Efficiency ◽  
Published Data ◽  
Blade Row ◽  
Performance Deterioration

Aircraft engine performance deterioration due to particle deposition on compressor blading and end walls gradually progresses with increasing time of operation. Deposition effects can be mitigated by on-wing maintenance actions. Application of condition based maintenance strategies in order to minimize operating costs requires high-grade physical deterioration models. In previous work, a model and experimental setup were developed to quantify both magnitudes and timescales of deposition effects on blade row performance as a function of engine operating time. The model and experimental data published therein were now used to predict the deteriorated performance of aircraft engine high-pressure compressors. A given procedure to analytically derive stage characteristics from blade row data was altered in such a way as to account for stage performance deterioration through a set of modifiers. These time-dependent modifiers were calculated from the blade row performance deterioration model. As an example of application, the stage characteristics of the NASA Energy Efficient Engine high-pressure compressor were derived from published data. The stage characteristics were gradually modified according to the aforementioned approach. A stage-stacking procedure was then used to calculate the full map of the deteriorated compressor. Results showed a gradually progressing shift of compressor speed lines to lower mass flows and pressure ratios as well as a collapsing of efficiency isolines. The design point of the new engine and the point of maximum efficiency no longer coincide. Maximum efficiency decreased. The methodology presented enables aircraft engine operators to predict individual engine on-wing recoverable performance deterioration to optimize maintenance scheduling and, thus, reduce operating costs.

scholarly journals Computational Simulation of Deposition in a Cooled High-Pressure Turbine Stage With Hot Streaks

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
High Pressure ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Computational Simulation ◽  
Stokes Number ◽  
Navier Stokes ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Tracking Model

Ash particle deposition in a high-pressure turbine stage was numerically investigated using steady Reynolds-averaged Navier-Stokes (RANS) and unsteady Reynolds-averaged Navie-Stokes (URANS) methods. An inlet temperature profile consisting of Gaussian nonuniformities (hot streaks) was imposed on the vanes, with vane cooling simulated using a constant vane wall temperature. The steady case utilized a mixing plane at the vane–rotor interface, while a sliding mesh was used for the unsteady case. Corrected speed and mass flow were matched to an experiment involving the same geometry, so that the flow solution could be validated against measurements. Particles ranging from 1 to 65 μm were introduced into the vane domain, and tracked using an Eulerian–Lagrangian tracking model. A novel particle rebound and deposition model was employed to determine particles' stick/bounce behavior upon impact with a surface. Predicted impact and capture distributions for different diameters were compared between the steady and unsteady methods, highlighting effects from the circumferential averaging of the mixing plane. The mixing plane simulation was found to generally under predict impact and capture efficiencies compared with the unsteady calculation, as well as under predict particle temperature upon impact with the blade surface. Quantitative impact and capture efficiency trends with the Stokes number are discussed for both the vane and blade, with companion qualitative distributions for the different Stokes regimes.

Forced Response Experiments in a High Pressure Turbine Stage

2002 ◽  
Author(s):  
Holger Hennings ◽  
Robert Elliott
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Forced Response ◽  
Flexible Rotor ◽  
High Pressure Turbine ◽  
Validation Data ◽  
Pressure Transducers ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

An experimental investigation was conducted on a single stage high pressure turbine in order to gain a deeper unterstanding of turbine blade forced response. In particular the main objective of this experiment was to obtain good quality validation data for the prediction methods used by major engine manufacturers. The stage investigated consists of an uncooled nozzle guide vane (NGV) and a rotor with 64 blades. To study the complete forced response problem a so called Flexible Rotor was designed and manufactured. This rotor has three modes of interest in the operating range of the stage: first torsion, second flap and second edge. The design of the experiment was supported by detailed CFD and structural analysis. The mechanical behavior of the Flexible Rotor is well known. In order to identify all interesting modes all blades are equipped with strain gauges individually calibrated. To check the unsteady pressures 18 unsteady pressure transducers were mounted at midspan. This paper deals with experiments only with the Flexible Rotor. Forced response results are presented for the first torsion mode at two different pressure ratios. The results obtained show a large scatter for the maximum response amplitudes at each pressure ratio. The distribution of the amplitudes around the disk is controlled by the mechanical properties of the rotor.

Computational Simulation of Deposition in a Cooled High-Pressure Turbine Stage With Hot Streaks

2016 ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
High Pressure ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Computational Simulation ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Suction Surface ◽  
Pressure Surface ◽  
Tracking Model

Ash particle deposition in a high-pressure turbine stage was numerically investigated using steady (RANS) and unsteady (URANS) methods. An inlet temperature profile consisting of Gaussian non-uniformities (hot streaks) was imposed on the vanes, with vane cooling simulated using a constant vane wall temperature. The steady case utilized a mixing plane at the vane-rotor interface, while a sliding mesh was used for the unsteady case. Corrected speed and mass flow were matched to an experiment involving the same geometry, so that the flow solution could be validated against measurements. Particles ranging from 1 to 65 μm were introduced into the vane domain, and tracked using an Eulerian-Lagrangian tracking model. A novel particle rebound and deposition model was employed to determine particles’ stick/bounce behavior upon impact with a surface. Predicted impact and capture distributions for different diameters were compared between the steady and unsteady methods, highlighting effects from the circumferential averaging of the mixing plane. The mixing plane simulation was found to over predict impact and capture efficiencies compared with the unsteady calculation, as well as over predict particle temperature upon impact with the blade surface. Blade impact efficiencies increased with higher Stokes numbers in both simulations, with multiple rebounds occurring on the pressure surface in the mixing plane case, and on the suction surface in the unsteady case.

scholarly journals A method for the assessment of operational severity for a high pressure turbine blade of an aero-engine

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Anthony Haslam ◽  
Abdullahi Abu ◽  
Panagiotis Laskaridis
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Damage Model ◽  
Engine Performance ◽  
Leading Edge ◽  
Operational Parameters ◽  
Transfer Coefficients ◽  
High Pressure Turbine ◽  
Aero Engine

Abstract This paper provides a tool for the estimation of the operational severity of a high pressure turbine blade of an aero engine. A multidisciplinary approach using aircraft/ engine performance models which provide inputs to a thermo-mechanical fatigue damage model is presented. In the analysis, account is taken of blade size, blade metal temperature distribution, relevant heat transfer coefficients and mechanical and thermal stresses. The leading edge of the blade is selected as the critical part in the estimation of damage severity for different design and operational parameters. The study also suggests a method for production of operational severity data for the prediction of maintenance intervals.

Sign in / Sign up

Export Citation Format

Share Document