A New Multistage Axial Compressor Designed With the Apnasa Multistage CFD Code: Part 1 — Code Calibration

2001 ◽  
Author(s):  
M. Mansour ◽  
S. Hingorani ◽  
Y. Dong
Keyword(s):  
Test Data ◽  
Flow Behavior ◽  
Measurement Data ◽  
Axial Compressor ◽  
Design Tool ◽  
Paper Test ◽  
Airfoil Optimization ◽  
Axial Compressors ◽  
Radial Profiles ◽  
Multistage Axial Compressor

The NASA Average-Passage multistage turbomachinery flow analysis code “APNASA” by J.J. Adamczyk (1985) has been validated, calibrated, and demonstrated at Honeywell Engines and Systems for the design of multistage axial compressors. APNASA was first calibrated against test data of two existing compressors and then used as a design tool in the design of a new modern multistage axial compressor. The results of the calibration, design effort, and the data measurements are presented in this two-part paper. In the present paper (Part 1) the results of the calibration for two multistage axial compressors are presented. The first compressor consists of four axial stages that were designed in the mid 1980s. The second compressor consists of three axial stages and was designed in the mid 1990s using viscous, three-dimensional CFD code, with airfoil optimization performed in single blade row fashion. The calibration work was aimed at developing meshing and modeling best practices and validating the code capability to simulate flow behavior in a multistage environment. Predictions are compared with test data for the axial compressor overall performance, individual stage performance, and detailed radial profiles at the stator vanes leading edge planes, throughout the compressor. Results show good agreement between APNASA predictions and measurement data. In particular, the results clearly demonstrate the ability of APNASA to capture the stage matching of multistage machines. As a result of this calibration/validation work, a new multistage axial compressor was subsequently designed, by using APNASA as the primary source of information for airfoil optimization (presented as Part 2 of this paper). Test results for the new compressor reveal that the design achieved its performance and operability goals in its first build. Details of the compressor design philosophy using APNASA and the comparison between APNASA simulation results and test data are presented in Part 2.

Off-Design Prediction of Transonic Axial Compressors: Part 1 — Mean-Line Code and Tuning Factors

2018 ◽  
Author(s):  
John Kidikian ◽  
Marcelo Reggio
Keyword(s):  
Pressure Ratio ◽  
Axial Compressor ◽  
Design Tool ◽  
Information Storage ◽  
Axial Compressors ◽  
Design Performance ◽  
Engineering Software ◽  
Line Loss ◽  
Loss Modelling ◽  
Line Analysis

With yearly advances in CFD techniques and methodologies, and the increased capacity and capabilities of computer CPU, GPU, and information storage, CFD has become a powerful design tool. However, despite its vast strengths, a CFD analysis is still based on the sound development of the 1D mean-line analysis methodology. This paper (part 1 of 2) describes an off-design axial compressor mean-line code, tested in a specialized engineering software for the development and analysis of a whole gas turbine engine, and the various tuning factors used to obtain an off-design performance match. It will be shown that, to obtain a proper match of the off-design performance of single-stage transonic axial compressors, both the rotor and stage pressure ratio, and the rotor temperature ratio are required to be converged upon. To do so, the off-design mean-line analysis requires the incorporation of a set of inlet & exit blockage factors and deviation angles that vary with the compressor performance conditions. This approach differs from the literature-based procedural assumptions (or rule-of-thumb) of fixed inlet and exit blockage factors of approximately “0.98”, and the use of a unique deviation angle based on Carter’s rule. The results obtained in this paper are then used to develop a generalized off-design mean-line loss modelling methodology (part 2 of 2) capable of predicting the off-design performance of four well documented NASA transonic axial compressors.

Considerations for Using 3D Pneumatic Probes in High Speed Axial Compressors

2002 ◽  
Author(s):  
Simon Coldrick ◽  
Paul Ivey ◽  
Roger Wells
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Probe Type ◽  
Calibration Data ◽  
Axial Compressors ◽  
Close Proximity ◽  
Multistage Axial Compressor ◽  
Preparatory Work

This paper describes preparatory work towards three dimensional flowfield measurements downstream of the rotor in an industrial, multistage, axial compressor, using a pneumatic pressure probe. The probe is of the steady state four hole cobra probe type. The design manufacture and calibration of the probe is described. CFD calculations have been undertaken in order to assess the feasability of using such a probe in the high speed compressor environment where space is limited. This includes effects of mounting the probe in close proximity to the downstream stator blades and whether it is necessary to adjust the calibration data to compensate for these effects.

Modeling of Axial Compressor with Large Tip Clearances

2021 ◽  
pp. 1-27
Author(s):  
Simon Evans ◽  
Junsok Yi ◽  
Sean Nolan ◽  
Liselle Joseph ◽  
Michael Ni ◽  
...  
Keyword(s):  
Technology Development ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Core Size ◽  
Tip Leakage Flow ◽  
Axial Compressors ◽  
Tip Leakage ◽  
Mesh Topology ◽  
Radial Profiles ◽  
Predictive Design

Abstract In the drive for lower fuel consumption, engine designs for the next generation of single-aisle aircraft will require core sizes below 3 lb/s and OPRs above 50. Traditionally, these core sizes are the domain of centrifugal compressors, but materials limit OPR in these machines. An all-axial HPC at this core size, however, comes with limitations associated with the small blade spans at the back of the HPC, as clearances, fillets and leading edges do not scale with the core size. The result is a substantial efficiency penalty, driven primarily by the tip leakage flow produced by the larger clearance-to-span ratio. To enable small-core, high-OPR, all-axial compressors, mitigating technologies need to be developed and implemented to reduce this penalty. For this technology development to be successful, it is imperative that predictive design tools accurately model the overall flow physics and trends of the technologies developed. In this paper we describe an effort to determine whether different modeling standards are required for large clearance-to-span ratios, and if so, identify criteria for an appropriate solver and/or mesh. Multiple models are run and results compared with data collected in the NASA-GRC Low-Speed Axial Compressor. These comparisons show that steady RANS solvers can predict the pressure-rise characteristic to an acceptable level of accuracy, if careful attention is paid to mesh topology in the tip region. However, unsteady tools are necessary to accurately capture radial profiles of blockage and total pressure.

Advanced Nonaxisymmetric Endwall Contouring for Axial Compressors by Generating an Aerodynamic Separator—Part I: Principal Cascade Design and Compressor Application

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Christian Dorfner ◽  
Alexander Hergt ◽  
Eberhard Nicke ◽  
Reinhard Moenig
Keyword(s):  
Flow Behavior ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Significant Loss ◽  
Optimization Techniques ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Axial Compressors ◽  
Endwall Contouring ◽  
Automated Optimization

Modern methods for axial compressor design are capable of shaping the blade surfaces in a three-dimensional way. Linking these methods with automated optimization techniques provides a major benefit to the design process. The application of nonaxisymmetric contoured endwalls is considered to be very successful in turbine rotors and vanes. Concerning axial compressors, nonaxisymmetric endwalls are still a field of research. This two-part paper presents the recent development of a novel endwall design. An aerodynamic separator, generated by a nonaxisymmetric endwall groove, interacts with the passage vortex. This major impact on the secondary flow results in a significant loss reduction because of load redistribution, reduction in recirculation areas, and suppressed corner separation. The first paper deals with the development of the initial endwall design using a linear compressor cascade application. A brief introduction of the design methods is provided, including the automated optimization and the 3D process chain with a focus on the endwall contouring tool. Hereafter, the resulting flow phenomena and physics due to the modified endwall surface are described and analyzed in detail. Additionally, the endwall design principal is transferred to an axial compressor stage. The endwall groove is applied to the hub and casing endwalls of the stator, and the initial numerical investigation is presented. For highly loaded operating points, the flow behavior at the hub region can be improved in accord with the cascade results. Obviously, the casing region is dominated by the incoming tip vortex generated by the rotor and still remains an area for further investigations concerning nonaxisymmetric endwall contouring.

Influence of different loads on the stresses of multistage axial compressor rotors

2016 ◽  
Vol 231 (5) ◽  
pp. 787-798 ◽  
Author(s):  
Xinqian Zheng ◽  
Chuang Ding ◽  
Yangjun Zhang
Keyword(s):  
Thermal Load ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Load ◽  
Design Phase ◽  
Total Stress ◽  
Axial Compressors ◽  
Centrifugal Load ◽  
Last Stage ◽  
Multistage Axial Compressor

Multistage axial compressors are widely used in the gas turbine engines. The strength of rotors is one of the key factors for the reliability of multistage axial compressors. The stresses of rotors at real working conditions can be caused by the centrifugal load, thermal load, and aerodynamic load. It is important to figure out the roles and the mechanism of the three kinds of loads in the stresses generating process. In this paper, the stresses of rotors in a typical five-stage axial compressor are calculated with different kinds of loads by solid–fluid coupling method. The results show that the proportion of the stress caused by centrifugal load is more than 80% of the total stress, which is dominant. The maximum proportion of the stress caused by thermal load is about 20% of the total stress at the front stages. However, the influence of thermal load is quite different from the first stage to the last stage. It is surprising that thermal load can decrease the stresses of the last stage rotor, which is mainly because of the variation of radial temperature gradient at disks for different stages. The proportion of the stress caused by aerodynamic load is usually less than 4%, and it tends to make the stresses at the suction side of the blades lower and enlarge it at the pressure side. According to the above results, centrifugal load is necessary of consideration at the conceptual design phase for the multistage axial compressor rotors. At preliminary three-dimensional design phase, centrifugal load and thermal load should be considered together. At optimized three-dimensional design phase, aerodynamic load cannot be neglected and all the three loads should be considered.

Multistage Axial Compressor Flow Field Predictions Using CFD and Through-Flow Calculations

2016 ◽  
Author(s):  
Milan Banjac ◽  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Axial Compressor ◽  
Operating Conditions ◽  
Test Cases ◽  
Axial Compressors ◽  
Geometric Configurations ◽  
Through Flow ◽  
Blade Row ◽  
Operation Parameters ◽  
Flow Variables ◽  
Multistage Axial Compressor

A comparison between two different methods for aerodynamic calculation of multistage axial compressors is presented. Results obtained using classical 2D through-flow calculations were compared with CFD results for several test cases, including various subsonic and supersonic multistage axial compressors with different geometric configurations and stage operating parameters. Calculated flow fields were compared in terms of overall compressor performances, individual blade row operation parameters and spanwise distributions of different flow variables. Nominal and off-design compressor operating conditions were analyzed and all the results were compared with experimental data. Accuracy, advantages and differences between individual methods are discussed.

A Three-Dimensional Unsteady Through-Flow Model for Rotating Stall in Axial Compressors

2020 ◽  
Author(s):  
Jin Guo ◽  
Jun Hu ◽  
Xuegao Wang ◽  
Rong Xu
Keyword(s):  
Flow Model ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Design Stage ◽  
Preliminary Evaluation ◽  
Source Terms ◽  
Axial Compressors ◽  
Through Flow

Abstract Rotating stall is a natural limit to the stable operating range of compressors due to the inverse pressure gradient of viscous gas. Effective prediction of compressor stall boundary is an important guarantee for the successful development of aeroengine. In this paper, a three-dimensional unsteady through-flow model based on body force theory is developed to reflect the dynamic stall process of multistage axial compressors with acceptable computational costs. The influence of blade geometric parameters is fully considered in blade force source terms. The source terms are related to the attack angle and Mach number of the blade inlet using the deviation angle and loss model in the through-flow theory. Meanwhile, the temporal lag response of the source terms to the upstream flow conditions is taken into account. Therefore, it can be utilized for predicting the off-design performance and rotating stall characteristics of multistage axial compressors. The developed model is validated on a two-stage low-speed axial compressor. The calculated performance line and stall cell speed are in agreement with the experimental results. The unsteady flow behavior of the compressor during stall is presented by the model. The results indicate that the developed model has the potential to be applied to the preliminary evaluation of compressor stability in design stage.

Maximum Loading Capacity of Tandem Blades in Axial Compressors

2018 ◽  
Author(s):  
Baojie Liu ◽  
Du Fu ◽  
Xianjun Yu
Keyword(s):  
Axial Compressor ◽  
Pressure Rise ◽  
Design Tool ◽  
Stable Operation ◽  
Loading Capacity ◽  
Axial Compressors ◽  
Maximum Loading ◽  
Work Input ◽  
Dimensional Parameters ◽  
Highly Loaded

Tandem blades are widely reported to be superior to a single-blade configuration under the aerodynamic circumstance with a large flow turning in a stator or a high work input in a rotor. Aiming at the design of a highly loaded rear stage of a high pressure compressor with the advanced concept, the maximum loading capacity of a tandem-blade configuration, which is rarely described in open literature, is fundamentally necessary to be explicit in order to determine a stable operation range. A diffuser analogy is carefully carried out between the tandem-blade geometry and the diffuser passage using a reliable and robust numerical method. The analysis approach to effectively predicting the maximum static pressure rise is verified by the limited results of computational fluid dynamics (CFD) and experiments. In addition, the maximum loading capacity of the tandem-blade configuration is compared with that of the single-blade configuration to define a more favorable design range of meanline parameters. The results indicate that the tandem blade outperforms the conventional blade in a specific design space and the approach can be a potential design tool to guide the selection of one-dimensional parameters of tandem blades in a highly loaded axial compressor.

Considerations for Using 3-D Pneumatic Probes in High-Speed Axial Compressors

2003 ◽  
Vol 125 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Simon Coldrick ◽  
Paul Ivey ◽  
Roger Wells
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Probe Type ◽  
Calibration Data ◽  
Axial Compressors ◽  
Close Proximity ◽  
Multistage Axial Compressor ◽  
Preparatory Work

This paper describes preparatory work towards three-dimensional flowfield measurements downstream of the rotor in an industrial, multistage, axial compressor, using a pneumatic pressure probe. The probe is of the steady-state four-hole cobra probe type. The design manufacture and calibration of the probe is described. CFD calculations have been undertaken in order to assess the feasibility of using such a probe in the high-speed compressor environment where space is limited. This includes effects of mounting the probe in close proximity to the downstream stator blades and whether it is necessary to adjust the calibration data to compensate for these effects.

Unsteady Operative Conditions of Bleeding Lines in Heavy Duty Axial Gas Turbine

2015 ◽  
Author(s):  
Marco Cioffi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Flow Behavior ◽  
Axial Compressor ◽  
Heavy Duty ◽  
Fast Evaluation ◽  
Axial Compressors ◽  
Proper Design ◽  
Valve Opening ◽  
Start Ups

The proper design and operation of air bleeding pipes (blow-off lines) from axial compressors in heavy duty gas turbines is relevant to protect the compressor during start-ups and shut-downs by avoiding dangerous flow instabilities in the first stages. The blow-off lines are usually equipped by valves, which are closed during normal gas turbine operation and opened at low rotor speed. During gas turbine shut-downs the blow-off valves open instantaneously. In this paper the unsteady flow behavior in blow-off lines following the valve opening is presented together with numerical results based on available field data. The paper main scope is to address and to help the design of experimental activities on production gas turbines and to make available some simple numerical tools to be adopted during the industrial design of an axial compressor and its auxiliary systems. The performed analysis results have been used to define the structural requirements and the correct positioning of the measuring probes installed in blow-off lines. In addition the presented models are part of the compressor design loop, used to compute a fast evaluation of the limiting mass flow rate, which characterizes the blow-off pipes as gas turbine safety devices.

Sign in / Sign up

Export Citation Format

Share Document