Similarity Transformations for Compressor Blading

1992 ◽  
Vol 114 (3) ◽  
pp. 561-568 ◽  
Author(s):  
N. G. Zhu ◽  
L. Xu ◽  
M. Z. Chen
Keyword(s):  
High Speed ◽  
Low Speed ◽  
Axial Compressors ◽  
Transformation Rules ◽  
Similarity Transformations ◽  
High Pressure Compressor ◽  
Experimental Validations ◽  
Model Compressor ◽  
Global Similarity ◽  
Pressure Compressor

Improving the performance of high-speed axial compressors through low-speed model compressor testing has proved to be economical and effective (Wisler, 1985). The key to this technique is to design low-speed blade profiles that are aerodynamically similar to their high-speed counterparts. The conventional aerodynamic similarity transformation involves the small disturbance potential flow assumption; therefore, its application is severely limited and generally not used in practical design. In this paper, a set of higher order transformation rules are presented that can accommodate large disturbances at transonic speed and are therefore applicable to similar transformations between the high-speed high-pressure compressor and its low-speed model. Local linearization is used in the nonlinear equations and the transformation is obtained in an iterative process. The transformation gives the global blading parameters such as camber, incidence, and solidity as well as the blade profile. Both numerical and experimental validations of the transformation show that the nonlinear similarity transformations do retain satisfactory accuracy for highly loaded blades up to low transonic speeds. Further improvement can be made by only slightly modifying profiles numerically without altering the global similarity parameters.

scholarly journals Similarity Transformations for Compressor Blading

1991 ◽  
Author(s):  
N. G. Zhu ◽  
L. Xu ◽  
M. Z. Chen
Keyword(s):  
High Speed ◽  
Linear Equations ◽  
Low Speed ◽  
Axial Compressors ◽  
Transformation Rules ◽  
Similarity Transformations ◽  
Non Linear ◽  
Experimental Validations ◽  
Model Compressor ◽  
Global Similarity

Improving the performance of high speed axial compressors through low speed model compressor testing has proved to be economical and effective (Wisler, 1984). The key to this technique is to design low speed blade profiles which are aerodynamically similar to their high speed counterparts. The conventional aerodynamic similarity transformation involves the small disturbance potential flow assumption therefore its application is severely limited and generally not used in practical design. In this paper, a set of higher order transformation rules are presented which can accommodate large disturbances at transonic speed and are therefore applicable to similar transformations between the high speed HP compressor and its low speed model. Local linearization is used in the non–linear equations and the transformation is obtained in an iterative process. The transformation gives the global blading parameters such as camber, incidence and solidity as well as the blade profile. Both numerical and experimental validations of the transformation show that the non–linear similarity transformations do retain satisfactory accuracy for highly loaded blades up to low transonic speeds. Further improvement can be made by only slightly modifing profiles numerically without altering the global similarity parameters.

Numerical Simulation of Particulates in Multistage Axial Compressors

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Swati Saxena ◽  
Giridhar Jothiprasad ◽  
Corey Bourassa ◽  
Byron Pritchard
Keyword(s):  
High Pressure ◽  
Axial Compressor ◽  
Airborne Particulate Matter ◽  
Spherical Particles ◽  
Nonspherical Particles ◽  
Qualitative Comparison ◽  
Axial Compressors ◽  
Sand Erosion ◽  
High Pressure Compressor ◽  
Pressure Compressor

Aircraft engines ingest airborne particulate matter, such as sand, dirt, and volcanic ash, into their core. The ingested particulate is transported by the secondary flow circuits via compressor bleeds to the high pressure turbine and may deposit resulting in turbine fouling and loss of cooling effectiveness. Prior publications focused on particulate deposition and sand erosion patterns in a single stage of a compressor or turbine. This work addresses the migration of ingested particulate through the high pressure compressor (HPC) and bleed systems. This paper describes a 3D CFD methodology for tracking particles along a multistage axial compressor and presents particulate ingestion analysis for a high pressure compressor section. The commercial CFD multiphase solver ANSYS CFX® has been used for flow and particulate simulations. Particle diameters of 20, 40, and 60 μm are analyzed. Particle trajectories and radial particulate profiles are compared for these particle diameters. The analysis demonstrates how the compressor centrifuges the particles radially toward the compressor case as they travel through the compressor; the larger diameter particles being more significantly affected. Nonspherical particles experience more drag as compared to spherical particles, and hence a qualitative comparison between spherical and nonspherical particles is shown.

Design Work of a Compressor Stage Through High-To-Low Speed Compressor Transformation

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Zhang Chenkai ◽  
Hu Jun ◽  
Wang Zhiqiang ◽  
Gao Xiang
Keyword(s):  
High Pressure ◽  
Axial Compressor ◽  
Design Procedure ◽  
Parameter Design ◽  
Design Work ◽  
Global Parameter ◽  
Low Speed ◽  
High Pressure Compressor ◽  
Pressure Compressor ◽  
Modeling Principles

Low-speed model testing has advantages such as great accuracy and low cost and risk, so it is widely used in the design procedure of the high pressure compressor (HPC) exit stage. The low-speed model testing project is conducted in Nanjing University of Aeronautics and Astronautics (NUAA) to represent aerodynamic load and flow field structure of the seventh stage of a high-performance ten-stage high-pressure compressor. This paper outlines the design work of the low speed four-stage axial compressor, the third stage of which is the testing stage. The first two stages and the last stage provide the compressor with entrance and exit conditions, respectively. The high-to-low speed transformation process involves both geometric and aerodynamic considerations. Accurate similarities demand the same Mach number and Reynolds number, which will not be maintained due to motor power/size and its low-speed feature. Compromises of constraints are obvious. Modeling principles are presented in high-to-low speed transformation. Design work was carried out based on these principles. Four main procedures were conducted successively in the general design, including establishment of low-speed modeling target, global parameter design of modeling stage, throughflow aerodynamic design, and blading design. In global parameter design procedure, rotational speed, shroud diameter, hub-tip ratio, midspan chord, and axial spacing between stages were determined by geometrical modeling principles. During the throughflow design process, radial distributions of aerodynamic parameters such as D-factor, pressure-rise coefficient, loss coefficients, stage reaction, and other parameters were obtained by determined aerodynamic modeling principles. Finally, rotor and stator blade profiles of the low speed research compressor (LSRC) at seven span locations were adjusted to make sure that blade surface pressure coefficients agree well with that of the HPC. Three-dimensional flow calculations were performed on the low-speed four-stage axial compressor, and the resultant flow field structures agree well with that of the HPC. It is worth noting that a large separation zone appears in both suction surfaces of LSRC and HPC. How to diminish it through 3D blading design in the LSRC test rig is our further work.

Transient Behavior in Axial Compressors in Event of Ice Shed

2015 ◽  
Author(s):  
Swati Saxena ◽  
Rajkeshar Singh ◽  
Andrew Breeze-Stringfellow ◽  
Tsuguji Nakano
Keyword(s):  
Transient Behavior ◽  
Energy Balance Equation ◽  
Control Mechanisms ◽  
Stall Inception ◽  
Axial Compressors ◽  
High Pressure Compressor ◽  
Blade Row ◽  
Total Thrust ◽  
Stall Control ◽  
Pressure Compressor

Incidents of partial or total thrust loss due to engine icing at cruise have been recorded over past several years. These events increase the demand for better understanding of compressor dynamics under such conditions. In the present study, physics based compressor blade row model (BRM) is used to evaluate the effect of booster ice-shed on axial high pressure compressor (HPC) at flight and approach idling conditions (65%–82% Nc). A representative aviation high-bypass turbofan engine HPC is used in this study. Transient behavior of compressor with varying ice ingestion conditions is compared and inter-stage dynamics is analyzed. Stage re-matching occurs due to heat exchange between air and ice which dictates the stall inception stage in the compressor. It is found that although T3 drop is closely related to compressor stall inception, the transient mechanism of ice-shed also plays an important role. Comparisons are made with steady energy balance equation to determine total water content (TWC) at HPC inlet to emphasize the importance of compressor transients. The ice amount, its ingestion duration and rate affect the onset of stall. HPC might sustain through a slower ice-shed while a faster ice-shed can lead to compressor stall with little or no chances of recovery. Understanding this transient behavior and inter-stage dynamics due to ice-shed will help in designing and implementing passive or active stall control mechanisms.

scholarly journals Research of the possibility of improving the traction and economic characteristics of a supersonic passenger aircraft engine through minimal modifications to the high-pressure compressor

2021 ◽  
Vol 2094 (4) ◽  
pp. 042055
Author(s):  
D Yu Strelets ◽  
S A Serebryansky ◽  
M V Shkurin
Keyword(s):  
High Pressure ◽  
Numerical Model ◽  
Thermodynamic Model ◽  
Gas Dynamics ◽  
High Speed ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
High Pressure Compressor ◽  
Passenger Aircraft ◽  
Pressure Compressor

Abstract In this paper, the possibilities of improving the traction and economic characteristics of a by-pass turbojet engine of a high-speed passenger aircraft due to minimal modifications of the high-pressure compressor. A thermodynamic model of the investigated engine of a new design in a three-dimensional layout was formed using an automated multicriteria optimization process. A computational assessment of the change in the characteristics of compressor modifications is carried out based on a numerical model of gas dynamics.

An Experimental Investigation of a Tandem Stator Flow Characteristic in a Low Speed Axial Research Compressor

2014 ◽  
Author(s):  
Alrik Tesch ◽  
Martin Lange ◽  
Konrad Vogeler ◽  
Jens Ortmanns ◽  
Erik Johann ◽  
...  
Keyword(s):  
Swirling Flow ◽  
Guide Vane ◽  
Axial Compressor ◽  
Low Speed ◽  
High Pressure Compressor ◽  
Oil Flow ◽  
Compressor Performance ◽  
Operating Points ◽  
Insight Into ◽  
Pressure Compressor

A major goal in axial compressor development is to increase the efficiency and to reduce the weight of the module. In order to do so the power density has to be increased by raising the work per stage. Higher capability to do work can be achieved by increasing the circumferential velocity component of the fluid. Tandem stators might offer the ability to turn high swirling flow with lower losses compared to a single blade stator. In terms of higher aerodynamic loading the use of tandem vanes can be a key feature to allow the design of highly efficient and compact compressor modules. This paper presents the design and experimental validation of a single stage low speed axial compressor with a tandem outlet guide vane, representative for a modern jet engine high pressure compressor. Additionally to the overall compressor performance the 3D flow field of the tandem stator has been measured with a five hole probe at different operating points. The results will be discussed in comparison with numerical results. Furthermore, oil flow pictures are used to get a deeper insight into flow conditions inside the vane passage and to validate the numerically predicted secondary flow structures.

scholarly journals Technology Making It Into Production

2009 ◽  
Vol 131 (03) ◽  
pp. 53-53
Author(s):  
Glinter Wilfert
Keyword(s):  
European Union ◽  
High Pressure ◽  
Heat Exchanger ◽  
High Speed ◽  
Low Pressure ◽  
The European Union ◽  
Low Pressure Turbine ◽  
High Pressure Compressor ◽  
Aero Engines ◽  
Pressure Compressor

This paper discusses the concept of MTU Aero Engines’ high-speed low-pressure turbine for the geared turbofan, which is based on the European Union research program ‘Clean’. Under the program, MTU developed the high-speed low-pressure turbine, the turbine centre frame, and an integrated heat exchanger. The paper also highlights that Pratt & Whitney, launched its geared turbofan (GTF) demonstrator project and asked MTU to be a partner. MTU has secured a 15 percent stake in either GTF version, which brings its high-speed low-pressure turbine, plus the first four stages of the high-pressure compressor.

Influence of Inlet Distortions on the Forced Vibration of a High Pressure Compressor Rig

2020 ◽  
Author(s):  
Falco Franz ◽  
Arnold Kühhorn ◽  
Thomas Giersch ◽  
Felix Figaschewsky ◽  
Sven Schrape
Keyword(s):  
Experimental Data ◽  
Forced Response ◽  
Axial Compressors ◽  
Aerodynamic Damping ◽  
Inlet Distortion ◽  
High Pressure Compressor ◽  
Engine Order ◽  
Amplitude Versus ◽  
Pressure Compressor ◽  
Superposition Effect

Abstract This paper aims at getting a better understanding of the simulative prediction of low engine order excitations in axial compressors. The focus is on the influence of inlet distortions on the forced response of a 4.5-stage research compressor rig. The papers starts with a brief description of the rig. After that the numerical setups required to conduct aerodynamic damping and forced response analyses are presented. Experimental data obtained during a rig test campaign show a significant response of a fundamental mode of the rotor 2 blisk to a low engine order 4. This resonance is studied throughout the paper. A superposition effect of different low engine order 4 sources was observed when changing the clocking of the inlet distortion. The vibrational amplitudes are computed using a subset of nominal system modes model incorporating a measured mistuning distribution. Measured amplitude versus blade patterns are compared with those computed by the aeromechanical models. The observed superposition effect is a key finding and is leveraged to establish comparability of the results.

scholarly journals The Unstable Behavior of Low and High Speed Compressors

1993 ◽  
Author(s):  
I. J. Day ◽  
C. Freeman
Keyword(s):  
High Speed ◽  
Effective Means ◽  
Laboratory Data ◽  
General Rule ◽  
Rotating Stall ◽  
Low Speed ◽  
Axial Compressors ◽  
High Speeds ◽  
New Information ◽  
Engine Compressor

By far the greater part of our understanding about stall and surge in axial compressors comes from work on low-speed laboratory machines. As a general rule, these machines do not model the compressibility effects present in high-speed compressors and therefore doubt has always existed about the application of low-speed results to high-speed machines. In recent years interest in active control has led to a number of studies of compressor stability in engine type compressors. The instrumentation used in these experiments has been sufficiently detailed that, for the first time, adequate data is available to make direct comparisons between high-speed and low-speed compressors. This paper presents new data from an eight-stage fixed geometry engine compressor and compares this with low-speed laboratory data. The results show remarkable similarities in both the stalling and surging behaviour of the two machines, particularly when the engine compressor is run at intermediate speeds. The engine results also show that, as in the laboratory tests, surge is precipitated by the onset of rotating stall. This is true even at very high speeds where it had previously been thought that surge might be the result of a blast wave moving through the compressor. This paper therefore contains new information about high-speed compressors and confirms that low speed testing is an effective means of obtaining insight into the behaviour of high-speed machines.

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