Deposition Pattern Analysis On a Fouled Multistage Test Compressor

2021 ◽  
Author(s):  
Alessio Suman ◽  
Alessandro Vulpio ◽  
Nicola Casari ◽  
Michele Pinelli ◽  
Rainer Kurz ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Deposition ◽  
Axial Compressor ◽  
Rotor Blades ◽  
Deposition Patterns ◽  
Compressor Inlet ◽  
Multistage Compressor ◽  
Multistage Test ◽  
Favorable Conditions ◽  
Multistage Axial Compressor

Abstract Compressor fouling is one of the main causes of gas turbine performance degradation. Microsized particles adhere to the blade surfaces increasing the surface roughness and modifying the airfoil shape. In the present work, the contamination of the Allison 250 C18 multistage compressor engine with four sorts of micrometric dust has been provided. The tests were performed changing the relative humidity at the compressor inlet and the unit rotational speed. After each test, a photographic inspection of the internal fouled parts has been realized and the digital pictures have been analyzed employing an image processing package. The deposits build-up of stator vanes and rotor blades have been postprocessed and the most affected regions of each compressor stage have been highlighted. Besides, a numerical simulation of the machine has been performed. The numerical flow field has been used to highlight the blade regions which show the most favorable conditions for particle deposition. A theoretical model has been applied to the flow field to simulate the particle deposition. The combination of the deposition model with the results of the CFD simulations gives the chance to better understand the experimentally-founded deposition patterns. Those results have been finally compared to the pictures of the patterns. The possibility to detect and measure the deposition patterns on a rotating test rig and the comparison with models and experiments gave the possibility to assess in detail the particle deposition phenomenon on a multistage axial compressor flow path.

Deposition Pattern Analysis on a Fouled Multistage Test Compressor

2020 ◽  
Author(s):  
Alessio Suman ◽  
Alessandro Vulpio ◽  
Nicola Casari ◽  
Michele Pinelli ◽  
Rainer Kurz ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Deposition ◽  
Axial Compressor ◽  
Rotor Blades ◽  
Deposition Patterns ◽  
Compressor Inlet ◽  
Multistage Compressor ◽  
Multistage Test ◽  
Favorable Conditions ◽  
Multistage Axial Compressor

Abstract Compressor fouling is one of the main causes of gas turbine performance degradation. Microsized particles adhere to the blade surfaces increasing the surface roughness and modifying the airfoil shape. In the present work, the contamination of the Allison 250 C18 multistage compressor engine with four sorts of micrometric dust has been provided. The tests were performed changing the relative humidity at the compressor inlet and the unit rotational speed. After each test, a photographic inspection of the internal fouled parts has been realized and the digital pictures have been analyzed employing an image processing package. The deposits build-up of stator vanes and rotor blades have been post-processed and the most affected regions of each compressor stage have been highlighted. Besides, a numerical simulation of the machine has been performed. The numerical flow field has been used to highlight the blade regions which show the most favorable conditions for particle deposition. A theoretical model has been applied to the flow field to simulate the particle deposition. The combination of the deposition model with the results of the CFD simulations gives the chance to better understand the experimentally-founded deposition patterns. Those results have been finally compared to the pictures of the patterns. The possibility to detect and measure the deposition patterns on a rotating test rig and the comparison with models and experiments gave the possibility to assess in detail the particle deposition phenomenon on a multistage axial compressor flow path.

Aerodynamic-Rotordynamic Interaction in Axial Compression Systems—Part I: Modeling and Analysis of Fluid-Induced Forces

2003 ◽  
Vol 125 (3) ◽  
pp. 405-415
Author(s):  
Ammar A. Al-Nahwi ◽  
James D. Paduano ◽  
Samir A. Nayfeh
Keyword(s):  
Flow Field ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Essential Element ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Analytical Models ◽  
Modeling And Analysis ◽  
Equal Importance ◽  
Consistent Treatment

This paper presents a first principles-based model of the fluid-induced forces acting on the rotor of an axial compressor. These forces are primarily associated with the presence of a nonuniform flow field around the rotor, such as that produced by a rotor tip clearance asymmetry. Simple, analytical expressions for the forces as functions of basic flow field quantities are obtained. These expressions allow an intuitive understanding of the nature of the forces and—when combined with a rudimentary model of an axial compressor flow field (the Moore-Greitzer model)—enable computation of the forces as a function of compressor geometry, torque and pressure-rise characteristics, and operating point. The forces predicted by the model are also compared to recently published measurements and more complex analytical models, and are found to be in reasonable agreement. The model elucidates that the fluid-induced forces comprise three main contributions: fluid turning in the rotor blades, pressure distribution around the rotor, and unsteady momentum storage within the rotor. The model also confirms recent efforts in that the orientation of fluid-induced forces is locked to the flow nonuniformity, not to tip clearance asymmetry as is traditionally assumed. The turning and pressure force contributions are shown to be of comparable magnitudes—and therefore of equal importance—for operating points between the design point and the peak of the compressor characteristic. Within this operating range, both “forward” and “backward” rotor whirl tendencies are shown to be possible. This work extends recent efforts by developing a more complete, yet compact, description of fluid-induced forces in that it accounts for all relevant force contributions, both tangential and radial, that may influence the dynamics of the rotor. Hence it constitutes an essential element of a consistent treatment of rotordynamic stability under the action of fluid-induced forces, which is the subject of Part II of this paper.

Fouling on a Multistage Axial Compressor in the Presence of a Third Substance at the Particle/Surface Interface

2018 ◽  
Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Devid Dainese ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Particle Surface ◽  
Axial Compressor ◽  
Micro Particles ◽  
Multistage Compressor ◽  
Particle Ingestion ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the compressor and turbine sections of gas turbines. In particular, in industrial applications, the micro-particles not captured by the air filtration system can cause deposits on blades and, consequently, can result in a decrease in compressor performance. It is of great interest to the industry to determine which zones of the compressor blades are impacted by these small particles. However, this information often refers to single stage analysis. This paper presents three-dimensional numerical simulations of the micro-particle ingestion (0.15 μm – 1.50 μm) in a multistage (i.e. eight stage) subsonic axial compressor, carried out by means of a commercial CFD code. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. The effects of humidity, or more generally, the effects of a third substance at the particle/surface interface (which is considered one of the major promoters of fouling) is then studied. The behavior of wet and oiled particles, in addition to the usual dry particles, is taken into consideration. In the dry case, the particle deposition is established only by using the sticking probability. This quantity links the kinematic characteristics of particle impact on the blade with the fouling phenomenon. In the other two cases, the effect of the presence of a third substance at the particle/surface interface is considered by means of an energy-based model. Moreover, the influence of the tangential impact velocity on particle deposition is analyzed. Introducing the effect of a third substance, such as humidity or oil, the phenomenon of fouling concerns the same areas of the multistage compressor. The most significant results are obtained by combining the effect of the third substance with the effect of the tangential component of the impact velocity of the particles. The deposition trends obtained with these conditions are comparable with those reported in literature, highlighting how the deposits are mainly concentrated in the early stages of a multistage compressor. Particular fluid dynamic phenomena, such as corner separations and clearance vortices, strongly influence the location of particle deposits.

scholarly journals Experimental Assessment of Fouling Effects in a Multistage Axial Compressor

2020 ◽  
Vol 197 ◽  
pp. 11007
Author(s):  
Nicola Casari ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Alessio Suman ◽  
Alessandro Vulpio
Keyword(s):  
Gas Turbine ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Small Scale ◽  
Performance Loss ◽  
Machine Performance ◽  
Internal Surfaces ◽  
Analysis Package ◽  
Multistage Axial Compressor

The study of the adhesion of micro sized particles to gas turbine internal surfaces, commonly known as gas turbine fouling, has gained increasing attention in the last years due to its dramatic effect on machine performance and reliability. On-field fouling analysis is mostly related to visual inspections during overhaul and/or programmed stops, which are performed, in particular, when gas turbine performance degradation falls under predetermined thresholds. However, these analyses, even if performed in the most complete as possible way, are rarely (or never) related to the conditions under which the gas turbine contamination takes place since the affecting parameters are difficult or even impossible to be adequately monitored. In the present work, a small scale multistage axial compressor is used to experimentally simulate the fouling phenomenon. The test rig allows the accurate control of the most relevant operating parameters which influence the fouling phenomenon. The compressor performance loss due to particle contamination has been quantitatively assessed. Soot particles appear stickier, especially in the presence of high humidity, and represent the most harmful operating conditions for the compressor unit. The deposits on the stator vanes and the rotor blades have been detected and post-processed, highlighting the most affected regions of each compressor stage employing an image analysis package tool.

Aerodynamic-Rotordynamic Interaction in Axial Compression Systems: Part I — Modeling and Analysis of Fluid-Induced Forces

2002 ◽  
Author(s):  
Ammar A. Al-Nahwi ◽  
James D. Paduano ◽  
Samir A. Nayfeh
Keyword(s):  
Flow Field ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Essential Element ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Analytical Models ◽  
Modeling And Analysis ◽  
Equal Importance ◽  
Consistent Treatment

This paper presents a first principles-based model of the fluid-induced forces acting on the rotor of an axial compressor. These forces are primarily associated with the presence of a nonuniform flow field around the rotor, such as that produced by a rotor tip clearance asymmetry. Simple, analytical expressions for the forces as functions of basic flow field quantities are obtained. These expressions allow an intuitive understanding of the nature of the forces and—when combined with a rudimentary model of an axial compressor flow field (the Moore-Greitzer model)—enable computation of the forces as a function of compressor geometry, torque and pressure-rise characteristics, and operating point. The forces predicted by the model are also compared to recently published measurements and more complex analytical models, and are found to be in reasonable agreement. The model elucidates that the fluid-induced forces comprise three main contributions: fluid turning in the rotor blades, pressure distribution around the rotor, and unsteady momentum storage within the rotor. The model also confirms recent efforts in that the orientation of fluid-induced forces is locked to the flow nonuniformity, not to tip clearance asymmetry as is traditionally assumed. The turning and pressure force contributions are shown to be of comparable magnitudes—and therefore of equal importance—for operating points between the design point and the peak of the compressor characteristic. Within this operating range, both “forward” and “backward” rotor whirl tendencies are shown to be possible. This work extends recent efforts by developing a more complete, yet compact, description of fluid-induced forces in that it accounts for all relevant force contributions, both tangential and radial, that may influence the dynamics of the rotor. Hence it constitutes an essential element of a consistent treatment of rotordynamic stability under the action of fluid-induced forces, which is the subject of Part II of this paper.

Experimental Investigation of a Stall Prediction System Using a Transonic Multistage Compressor

2007 ◽  
Author(s):  
Tomofumi Nakakita ◽  
Masahiro Kurosaki ◽  
Yukio Kamiyoshihara
Keyword(s):  
Axial Compressor ◽  
Prediction System ◽  
Test Results ◽  
Stall Margin ◽  
Pressure Transducers ◽  
Stator Vane ◽  
Multistage Compressor ◽  
Stall Warning ◽  
Stall Control ◽  
Multistage Axial Compressor

This paper describes the test results of a stall prediction system using a transonic multistage axial compressor. The test results show that there is a clear relationship between the stall margin and the stall-warning index measured at the first stage. The stall warning index is derived from auto correlation of casing wall pressure signals above the rotor tip. In the tests, the compressor installed with pressure transducers on the casing wall near the leading edges of the first three rotors was forced to stall while operating at a constant speed by closing the discharge valve. The test results where the stator vane settings of the first three stages were changed show that load distribution among stages does not have significant effects on the stall margin vs. stall-warning index relationship. Using some smoothing technique, undesired time variation of the stall-warning index can be reduced to the level necessary for practical active stall control with allowable response time delay.

Numerical Simulation of the Flow Field in a High Speed Multistage Compressor: Study of the Time Discretization Sensitivity

2015 ◽  
Author(s):  
Johannes Schreiber ◽  
Xavier Ottavy ◽  
Ghislaine Ngo Boum ◽  
Stéphane Aubert ◽  
Frédéric Sicot
Keyword(s):  
Flow Field ◽  
High Speed ◽  
State Of The Art ◽  
Axial Compressor ◽  
Time Discretization ◽  
Test Rig ◽  
Unsteady Rans ◽  
Multistage Compressor ◽  
Temporal Periodicity ◽  
Specific Contribution

The following numerical investigations are performed in the frame of a research project that aims at a better understanding of the flow unsteadiness that develops in a multistage high-speed axial compressor. First, the paper presents a new version of the 3.5 stages high-speed axial compressor CREATE (Compresseur de Recherche pour l’Etude des effets Aérodynamiques et TEchnologiques), which has been designed by Snecma and is based at the LMFA (Laboratory for Fluid Mechanics and Acoustics) on a 2MW test rig. This paper is based on numerical results obtained with 3D steady and unsteady RANS computations using the CREATE configuration. The unsteady RANS simulations are carried out over the whole spatial and temporal periodicity of the compressor. The main numerical setup has been fixed according to the state of the art. Second, the effect of three different time discretizations on the flow field in CREATE is discussed. The global performance of the compressor is not significantly affected. However the change in the time discretization impacts the structure of the flow at specific locations. The main focus of this study lies on the transport of flow structures and the analysis of their interactions. A double modal decomposition method, which highlights the specific contribution of the interactions on the overall flow field, is applied for the study of the highly complex and unsteady flow field. It allows identifying which interactions are more sensitive to the change in the time discretization.

scholarly journals МЕТОД РАСЧЁТА ТЕРМОГАЗОДИНАМИЧЕСКИХ ПАРАМЕТРОВ ТУРБОВАЛЬНОГО ГАЗОТУРБИННОГО ДВИГАТЕЛЯ НА ОСНОВЕ ПОВЕНЦОВОГО ОПИСАНИЯ ЛОПАТОЧНЫХ МАШИН. ЧАСТЬ II. ОПРЕДЕЛЕНИЕ ПАРАМЕТРОВ СТУПЕНЕЙ И МНОГОСТУПЕНЧАТЫХ КОМПРЕССОРОВ

2019 ◽  
pp. 18-28 ◽  
Author(s):  
Людмила Георгиевна Бойко ◽  
Александр Евгеньевич Демин ◽  
Наталия Владимировна Пижанкова
Keyword(s):  
Gas Turbine ◽  
Calculation Method ◽  
Axial Compressor ◽  
Flow Path ◽  
Dynamic Parameters ◽  
Operating Characteristics ◽  
Program Complex ◽  
Gas Dynamic ◽  
Multistage Compressor ◽  
Multistage Axial Compressor

Gas Turbine Engine (GTE) operating characteristics such as thrust (or power), specific fuel consumption and other cycle parameters on different regimes, can be determined by engine modeling and applying correspondent calculation method. Its accuracy is the function of the engine’s element maps definition precision. So these maps representations influence for engines investigation results significantly. Main points and equation system for engine performances calculation method were represented in Part I of this article. The method gives an opportunity for the flow path thermodynamical parameters and engine integral values analyzing by using multistage axial blade machines blade-to-blade descriptions. The compressor and gas turbine and parameters are getting by special program modules, adding to the engine operating characteristics investigation program complex. These modules use the flow path and cascade middle radius geometrical parameters as the data for calculation. The goal of this article is the representation of the method for axial stages and multistage compressors performances definition. The calculation technique is based on one-dimensional (1D) multistage axial compressor flow description. Proposed 1D flow analysis method allows to get the multistage axial compressor maps taking into account the blade-to-blade gaps flow bleeding and by-pass. The method including is founded on the thermal and gas dynamic equations and turbomachinery theoretical dependences and empirical functions for losses and deviation angles determination. Besides, the representing method allows to calculate gas dynamic parameters, velocity triangles, angles of attack, evaluate their deviations from optimal values, hydraulic losses. Also, it can show accordance of stages working on different regimes, find the stage, which is a reason for compressor instability, and stall margin. This method can be used in GTE mathematic simulation, founded on blade-to-blade description multistage blade machines or also in multistage compressor designing. The proposed method gives the opportunity to control the stator variable vanes stagger angles control and to analyze its influence for stage and multistage compressor gas dynamic parameters and maps.

Impact of Sweep on Part Speed Performance of an Axial Compressor Rotor With Circumferential Casing Grooves

2019 ◽  
Author(s):  
Shraman Goswami ◽  
M. Govardhan
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Field Investigation ◽  
Performance Comparison ◽  
Rotor Blades ◽  
Stall Margin ◽  
Compressor Rotor ◽  
Design Speed

Abstract High performance and increased operating range of an axial compressor is obtained by employing three-dimensional design features, such as sweep, as well as shroud casing treatments, such as circumferential casing grooves. A number of different rotor blades with different amounts of sweeps and different sweep starting spans are studied at design speed. Different swept rotors, including zero sweep, are derived from Rotor37 rotor geometry. In the current study the best performing rotor with sweep is analyzed at part speed. The analyses were done for baseline rotor, devoid of any sweep, and with and without circumferential casing grooves. A detailed flow field investigation and performance comparison is presented to understand the changes in flow field at part speed. It is found that that at 100% design speed, stall margin improvement is achived by both sweep and casing grooves, but at 90% speed improvement in stall margin due to sacing groove is very minimal over and above the gain due to sweep. It is also noticed that due to reduced shock loss efficiency is higher at 90% speed than at 100% speed.

Robust Design Strategies for Heavy Duty Axial Compressor Inlet Strut

2012 ◽  
Author(s):  
Marco Cioffi ◽  
Enrico Puppo ◽  
Andrea Silingardi ◽  
Mauro Macciò
Keyword(s):  
Power Plants ◽  
Axial Compressor ◽  
Heavy Duty ◽  
Design Strategies ◽  
Compressor Blades ◽  
Design Problems ◽  
Air Mass ◽  
Statistical Effect ◽  
Compressor Inlet ◽  
Multistage Axial Compressor

Novel procedures for the robust optimization of compressor blades are here presented and applied to the optimal design of the inlet duct struts of an heavy duty, multistage axial compressor. Different approaches can be adopted to properly define the struts actual inlet flow boundary conditions, which can be affected by spatial non-uniformity or uncertainness: suitable deterministic and stochastic approaches are therefore introduced. A number of blade solutions are computed and discussed. The presented procedures are able to find new struts geometries giving improved performances with respect to a reference strut, mainly with an air mass flow increase. In particular the proposed stochastic procedure seems to be quite appropriate for a large class of design problems with parameters fluctuation or to properly analyze the statistical effect of changing operative conditions occurrence in power plants.

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