scholarly journals Axial Compressor Mean-Line Analysis: Choking Modelling and Fully-Coupled Integration in Engine Performance Simulations

2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Ioannis Kolias ◽  
Alexios Alexiou ◽  
Nikolaos Aretakis ◽  
Konstantinos Mathioudakis
Keyword(s):  
Axial Compressor ◽  
Engine Performance ◽  
Engine Model ◽  
Multi Stage ◽  
Transient Simulations ◽  
Full Knowledge ◽  
Compressor Performance ◽  
First Time ◽  
Performance Calculation ◽  
Fully Coupled

A mean-line compressor performance calculation method is presented that covers the entire operating range, including the choked region of the map. It can be directly integrated into overall engine performance models, as it is developed in the same simulation environment. The code materializing the model can inherit the same interfaces, fluid models, and solvers, as the engine cycle model, allowing consistent, transparent, and robust simulations. In order to deal with convergence problems when the compressor operates close to or within the choked operation region, an approach to model choking conditions at blade row and overall compressor level is proposed. The choked portion of the compressor characteristics map is thus numerically established, allowing full knowledge and handling of inter-stage flow conditions. Such choking modelling capabilities are illustrated, for the first time in the open literature, for the case of multi-stage compressors. Integration capabilities of the 1D code within an overall engine model are demonstrated through steady state and transient simulations of a contemporary turbofan layout. Advantages offered by this approach are discussed, while comparison of using alternative approaches for representing compressor performance in overall engine models is discussed.

Axial Compressor Aerodynamics Under Sub-Idle Conditions

2013 ◽  
Author(s):  
Enric Illana ◽  
Nicholas Grech ◽  
Pavlos K. Zachos ◽  
Vassilios Pachidis
Keyword(s):  
Mach Number ◽  
Axial Compressor ◽  
Engine Performance ◽  
Separated Flow ◽  
Physical Parameters ◽  
Aerodynamic Coefficients ◽  
Low Speed ◽  
Multi Stage ◽  
Flow Phenomena ◽  
Compressor Performance

With stricter regulations on engine altitude relight capability, the understanding of low-speed axial compressor performance is becoming increasingly important. At such far off-design conditions, compressors behave differently from design point, with large changes in the flow phenomena and reduced reliability on the established empirical equations and assumptions. This work focuses on the aerodynamics of a locked-rotor axial compressor at high inlet Mach number conditions, using a validated numerical simulation approach. In a locked-rotor compressor there is very little compression of the inflow. The air is forced to accelerate, with the rear stages seeing the highest velocities. Depending on the inlet Mach number, the velocity at the rear stages can be close to sonic, until choking conditions are reached. To predict accurately the zero-speed compressor performance close to the choking point, the corresponding blade aerodynamic coefficients are evaluated as a function of the blade’s physical parameters and the inlet Mach number. In addition, the blockage due to the separated flow as a result of the high negative incidences is investigated as a function of inlet Mach number, incidence, solidity and stagger angle. Models that predict the characteristics and choking mass flow of the compressor, require such data. This work offers a better insight into the low-speed and locked rotor characteristics of the compressor. The zero-speed line can be calculated through a stage-stacking technique using the aerodynamic coefficients and flow blockage derived from the numerical simulations. Low-speed lines between the zero and idle-speed line can subsequently be created through interpolation. Using this methodology, it is possible to generate a complete sub-idle map for a multi-stage axial compressor, enhancing the predictive capability of whole engine performance solvers.

Compressor Performance 2D Modelling at Reverse Flow Conditions

2010 ◽  
Author(s):  
L. Gallar ◽  
I. Tzagarakis ◽  
V. Pachidis ◽  
R. Singh
Keyword(s):  
Experimental Data ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Engine Performance ◽  
Two Dimensional ◽  
Flow Conditions ◽  
Compressor Surge ◽  
Compressor Performance ◽  
Shaft Failure

After a shaft failure the compression system of a gas turbine is likely to surge due to the heavy vibrations induced on the engine after the breakage. Unlike at any other conditions of operation, compressor surge during a shaft over-speed event is regarded as desirable as it limits the air flow across the engine and hence the power available to accelerate the free turbine. It is for this reason that the proper prediction of the engine performance during a shaft over-speed event claims for an accurate modelling of the compressor operation at reverse flow conditions. The present study investigates the ability of the existent two dimensional algorithms to simulate the compressor performance in backflow conditions. Results for a three stage axial compressor at reverse flow were produced and compared against stage by stage experimental data published by Gamache. The research shows that due to the strong radial fluxes present over the blades, two dimensional approaches are inadequate to provide satisfactory results. Three dimensional effects and inaccuracies are accounted for by the introduction of a correction parameter that is a measure of the pressure loss across the blades. Such parameter is tailored for rotors and stators and enables the satisfactory agreement between calculations and experiments in a stage by stage basis. The paper concludes with the comparison of the numerical results with the experimental data supplied by Day on a four stage axial compressor.

Towards a Fully Coupled Component Zooming Approach in Engine Performance Simulation

2011 ◽  
Author(s):  
Julien Pilet ◽  
Jean-Loi¨c Lecordix ◽  
Nicolas Garcia-Rosa ◽  
Roger Bare`nes ◽  
Ge´rard Lavergne
Keyword(s):  
Engine Performance ◽  
Simulation Software ◽  
Performance Simulation ◽  
Engine Model ◽  
Component Models ◽  
Mapping Models ◽  
Fully Coupled ◽  
Bypass Ratio ◽  
Very High ◽  
Engine Cycle

This paper presents a fully-coupled zooming approach for the performance simulation of modern very high bypass ratio turbofan engines developed by Snecma. This simulation is achieved by merging detailed 3D simulations and map component models into a unified representation of the whole engine. Today’s state-of-the-art engine cycle analysis are commonly based on component mapping models which enable component interactions to be considered, while CFD simulations are carried out separately and therefore overlook those interactions. With the methodology discussed in this paper, the detailed analysis of an engine component is no longer considered apart, but directly within the whole engine performance model. Moreover, all links between the 3D simulation and overall engine models have been automated making this zooming simulation fully-integrated. The simulation uses the PROOSIS propulsion object-oriented simulation software developed by Empresarios Agrupados for whole engine cycle analysis and the computational fluid dynamics (CFD) code CEDRE developed by ONERA for the high fidelity 3-D component simulations. The whole engine model is created by linking component models through their communication ports in a graphical user-friendly interface. CFD simulated component models have been implemented in PROOSIS libraries already providing mapped components. Simple averaging techniques have been developed to handle 3D-to-0D data exchange. Boundary conditions of the whole engine model remain the same as for the typical 0-D engine cycle analysis while those of the 3-D simulations are automatically given by PROOSIS to CEDRE. This methodology has been applied on an advanced very high bypass ratio engine developed by Price Induction. The proposed zooming approach has been performed on the fan stage when simulating Main Design Point as well as severe case of off-design conditions such as wind-milling. The results have been achieved within the same time frame of a typical CFD fully-converged calculation. A detailed comparison with upcoming test results will provide a first validation of the methodology and will be presented in a future paper.

The Stacking of Compressor Stage Characteristics to Give an Overall Compressor Performance Map

1962 ◽  
Vol 13 (4) ◽  
pp. 349-367 ◽  
Author(s):  
M. D. C. Doyle ◽  
S. L. Dixon
Keyword(s):  
Axial Compressor ◽  
Compressor Stage ◽  
Individual Stage ◽  
Optimum Performance ◽  
Method Of Calculation ◽  
Multi Stage ◽  
Performance Map ◽  
Compressor Performance ◽  
Overall Performance ◽  
The Individual

SummaryA method of calculation is developed to compute the overall performance of a multi-stage axial compressor, from a knowledge of the individual stage characteristics, by a “stacking” technique. Compressor models are designed and their overall performance calculated. These results are compared to show, qualitatively, the effect of alterations in design and stage performance on overall performance and to find how compressors should be designed for optimum performance.

scholarly journals Performance Calculation of a Multi-Stage Axial Compressor through a Semi-Empirical Modelling Framework

2019 ◽  
Author(s):  
Samuel Cruz-Manzo ◽  
◽  
Senthil Krishnababu ◽  
Vili Panov ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Axial Compressor ◽  
Empirical Modelling ◽  
Modelling Framework ◽  
Multi Stage ◽  
Semi Empirical ◽  
Performance Calculation

The Performance Calculation Method of Fouled Axial Flow Compressor Based on the Stage Stacking Method

2014 ◽  
Vol 915-916 ◽  
pp. 301-304
Author(s):  
Hong Xu ◽  
Hua Dong Yang ◽  
Guang Ru Hua
Keyword(s):  
Calculation Method ◽  
Scaling Law ◽  
Axial Flow ◽  
Engine Performance ◽  
Axial Flow Compressor ◽  
Progression Model ◽  
Multi Stage ◽  
Multistage Compressor ◽  
Flow Compressor ◽  
Performance Calculation

Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. This paper develops a performance calculation method of fouled multi-stage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. In this model, the performance of the first section is obtained by stage stacking method by combining scaling law method, linear progression model with traditional stage stacking method. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method. Finally, the model is successfully applied to predict the 8-stage axial flow compressor.

Performance Model “Zooming” for In-Depth Component Fault Diagnosis

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
N. Aretakis ◽  
I. Roumeliotis ◽  
K. Mathioudakis
Keyword(s):  
Fault Diagnosis ◽  
Measurement Data ◽  
Engine Performance ◽  
Main Tool ◽  
Performance Model ◽  
Diagnostic Methods ◽  
Engine Model ◽  
Path Component ◽  
1D Model ◽  
Compressor Performance

A method giving the possibility for a more detailed gas path component fault diagnosis by exploiting the “zooming” feature of current performance modeling techniques is presented. A diagnostic engine performance model is the main tool that points to the faulty engine component. A diagnostic component model is then used to identify the fault. The method is demonstrated on the case of compressor faults. A 1D model based on the “stage stacking” approach is used to “zoom” into the compressors, supporting a 0D engine model. A first level diagnosis determines the deviation of overall compressor performance parameters while zooming calculations allow a localization of the faulty stages of a multistage compressor. The possibility to derive more detailed information with no additional measurement data is established by the incorporation of empirical knowledge on the type of faults that are usually encountered in practice. Although the approach is based on known individual diagnostic methods, it is demonstrated that the integrated formulation provides not only higher effectiveness but also additional fault identification capabilities.

Performance Analysis of a Low-Pressure Three-Stage Axial Compressor

2004 ◽  
Author(s):  
Sivakumar Subramanian ◽  
B. V. S. S. S. Prasad ◽  
S. Krishnan ◽  
C. Janakamma
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Low Pressure ◽  
Detailed Knowledge ◽  
Rotating Blade ◽  
Multi Stage ◽  
Challenging Tasks ◽  
Flow Features ◽  
Flow Through ◽  
Compressor Performance

Prediction of three-dimensional flow through a multi-stage axial compressor involving multiple frames of reference is one of the challenging tasks in CFD. When the axial gap between the stationary and rotating blade rows is reduced, the blade row interactions become important. Therefore, a detailed knowledge of flow features is essential for the optimum design of multi stage compressor. As the design and conduct of experiments and evaluation of compressor performance is expensive and time consuming, many aerospace industries prefer to obtain the same information by the computational efforts. In this context, a number of CFD codes for modelling and analysis of turbomachinery flows are used. The most exigent aspect of simulating multi-stage compressor is representing the interactions between the rotor and stator. The present work is to find out the best-suited method for the analysis of a low-pressure three-stage compressor that gives reliable results. The motivation for this effort is derived from the inability to consistently compare predicted performance parameters obtained from using the interface models with the experimental results, which is especially true for off-design operation.

Upgrade of a 16-Stage Industrial Compressor: Part I — Development of an Innovative Performance Analysis Method

2006 ◽  
Author(s):  
Magdy S. Attia
Keyword(s):  
Axial Compressor ◽  
Total Efficiency ◽  
Turbine Engine ◽  
Streamline Curvature ◽  
Multi Stage ◽  
Point Increase ◽  
Innovative System ◽  
Compressor Performance ◽  
Cycle Efficiency ◽  
Compressor Efficiency

The compressor belonging to a 165 MW-class gas turbine engine designed in the 1970’s with initial operation starting in the early 1980’s, is to be upgraded. The goal of the redesign is to develop a retrofittable upgrade which will deliver a 6% increase in flow and a 2-point increase in adiabatic total-to-total efficiency. The desired increase in compressor efficiency is equivalent to a 0.7-point increase in simple cycle efficiency, approximately. To initiate the upgrade process, a thorough performance evaluation of the existing configuration was needed using the current technology. In this case, the S1S2 prediction did not match measured performance to within an acceptable band. Therefore, a new and innovative system was developed to overcome the existing limitations. This paper presents a simple, physically sound, reliable, and efficient method for predicting axial compressor performance using a combination of single-row CFD and Streamline Curvature (Throughflow) codes. The method has been developed and tested on several industrial multi-stage compressors including this 16-stage compressor with excellent results.

Details of Shrouded Stator HUB Cavity Flow in a Multi-Stage Axial Compressor Part 2: Leakage Flow Characteristics in Stator Wells

2021 ◽  
Author(s):  
Nitya Kamdar ◽  
Fangyuan Lou ◽  
Nicole L. Key
Keyword(s):  
Flow Characteristics ◽  
Axial Compressor ◽  
Leakage Flow ◽  
Multi Stage ◽  
High Pressure Compressor ◽  
Present Part ◽  
Compressor Performance ◽  
The Impact ◽  
Shed Light ◽  
Pressure Compressor

Abstract In the first part of the paper, the influence of the hub leakage flow on compressor performance and its interactions with the primary flow were investigated. While the impact of hub leakage flow on the primary passage is readily available in the open literature, details inside the cavity geometry are scarce due to the difficulties in instrumenting that region for an experiment or modeling the full cavity geometry. To shed light on this topic, the flow physics in the stator cavity inlet and outlet wells were investigated in the present part of the paper to understand the flow path of the leakage fluid and windage heating within the cavity using a coupled CFD model with inclusion of the stator cavity wells for the Purdue 3-Stage (P3S) Axial Compressor, which is representative of the rear stages of a high-pressure-compressor in core engines.

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