An Analysis of Axial Compressor Cascade Aerodynamics: Part II—Comparison of Potential Flow Results With Experimental Data

1959 ◽  
Vol 81 (3) ◽  
pp. 379-386
Author(s):  
G. L. Mellor
Keyword(s):  
Experimental Data ◽  
Potential Flow ◽  
Lift Coefficient ◽  
Axial Compressor ◽  
Compressor Blade ◽  
Compressor Cascade ◽  
Interesting Point ◽  
Empirical Constant ◽  
Empirical Curve ◽  
Attack Data

The theoretical potential flow results of Part I are compared with the large number of NACA 65-series compressor blade data. It is found that a single empirical constant used to modify the theory permits reasonable predictions of turning or lift coefficient to be made for any cascade geometry in the unstalled regions of flow. Furthermore, it is demonstrated that the theory allows a considerable number of plus and minus stalling angle of attack data to be collapsed to a single empirical curve. Conversely such a curve, once established, allows stalling predictions to be made for any cascade geometry. One interesting point on this curve is the loading limit above which the cascade is always stalled.

Experimental and Numerical Study of the Response of an Axial Compressor to Distorted Inlet Flow

1988 ◽  
Vol 110 (4) ◽  
pp. 355-360 ◽  
Author(s):  
G. Billet ◽  
J. Huard ◽  
P. Chevalier ◽  
P. Laval
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Axial Compressor ◽  
Numerical Approach ◽  
Compressor Blade ◽  
Numerical Results ◽  
Test Stand ◽  
Viscous Effects ◽  
Inlet Flow

A model representing the response of fixed or rotating axial compressor blade-rows is coupled to a 3-D numerical simulation of the flow outside the blade rows. The code can be used to study nonuniform compressible 3-D flows through turbomachines. The fluid is assumed to be inviscid in the space outside the rows, while the viscous effects are taken into account inside. Numerical results are compared with experimental data obtained on a test stand with steady distorted inflow. This comparison shows that this numerical approach is capable of predicting the response of the compressor. This work is part of a larger project aimed at predicting the response of a compressor to a nonuniform inlet flow that is periodic in time, or fully unsteady.

scholarly journals The role of the leading edge vortex in lift augmentation of steadily revolving wings: a change in perspective

2017 ◽  
Vol 14 (132) ◽  
pp. 20170159 ◽  
Author(s):  
Mostafa R. A. Nabawy ◽  
William J. Crowther
Keyword(s):  
Experimental Data ◽  
Potential Flow ◽  
Normal Force ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Model Parameters ◽  
Force Model ◽  
Leading Edge Vortex ◽  
Edge Vortex

The presence of a stable leading edge vortex (LEV) on steadily revolving wings increases the maximum lift coefficient that can be generated from the wing and its role is important to understanding natural flyers and flapping wing vehicles. In this paper, the role of LEV in lift augmentation is discussed under two hypotheses referred to as ‘additional lift' and ‘absence of stall’. The ‘additional lift' hypothesis represents the traditional view. It presumes that an additional suction/circulation from the LEV increases the lift above that of a potential flow solution. This behaviour may be represented through either the ‘Polhamus leading edge suction' model or the so-called ‘trapped vortex' model. The ‘absence of stall' hypothesis is a more recent contender that presumes that the LEV prevents stall at high angles of attack where flow separation would normally occur. This behaviour is represented through the so-called ‘normal force' model. We show that all three models can be written in the form of the same potential flow kernel with modifiers to account for the presence of a LEV. The modelling is built on previous work on quasi-steady models for hovering wings such that model parameters are determined from first principles, which allows a fair comparison between the models themselves, and the models and experimental data. We show that the two models which directly include the LEV as a lift generating component are built on a physical picture that does not represent the available experimental data. The simpler ‘normal force' model, which does not explicitly model the LEV, performs best against data in the literature. We conclude that under steady conditions the LEV as an ‘absence of stall’ model/mechanism is the most satisfying explanation for observed aerodynamic behaviour.

An Analysis of Axial Compressor Cascade Aerodynamics: Part I—Potential Flow Analysis With Complete Solutions for Symmetrically Cambered Airfoil Families

1959 ◽  
Vol 81 (3) ◽  
pp. 362-377 ◽  
Author(s):  
G. L. Mellor
Keyword(s):  
Potential Flow ◽  
Flow Analysis ◽  
Angle Of Attack ◽  
Axial Compressor ◽  
Graphical Form ◽  
Compressor Cascade ◽  
Real Fluid ◽  
Flow Effects ◽  
Complete Solutions

A method is presented whereby complete potential flow solutions for any cascade geometry may be obtained with comparatively great rapidity on desk calculators. This solution is carried out for the case of symmetrically cambered airfoils such as the 65-series compressor and circular are airfoils and the results presented in a compact graphical form completely account for the potential flow effects of camber, profile, thickness, stagger, solidity, and angle of attack. Real fluid effects will be assessed and correlated in Part II using the present results as a supporting theory.

scholarly journals ОПРЕДЕЛЕНИЕ ДРОССЕЛЬНОЙ ХАРАКТЕРИСТИКИ ТУРБОВАЛЬНОГО ГТД НА ОСНОВЕ МЕТОДА МАТЕМАТИЧЕСКОГО МОДЕЛИРОВАНИЯ С ИСПОЛЬЗОВАНИЕМ ОДНО- И ДВУМЕРНЫХ ПОДХОДОВ К РАСЧЕТУ ПАРАМЕТРОВ КОМПРЕССОРА

2019 ◽  
pp. 21-30 ◽  
Author(s):  
Людмила Георгиевна Бойко ◽  
Вадим Анатольевич Даценко ◽  
Наталия Владимировна Пижанкова
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Rotational Speed ◽  
Axial Compressor ◽  
Gas Turbine Engine ◽  
Compressor Blade ◽  
Turbine Engine ◽  
Operation Modes ◽  
Multi Stage ◽  
Wide Range

The results of mathematical modeling processes in the turboshaft gas turbine engine (GTE) are presented. The using calculation method based on a high-level GTE mathematical model, which is founded on a multi-stage axial compressor blade-to-blade description. The model was developed at the Aviation Theory Chair of National Aerospace University “KhAI”. The model is based on a multistage axial compressor thermodynamic parameters calculations using a 1D and 2D approaches to analyzing of the flow. The model named above allows one to take into account air intakes from of the compressor blade gaps, as well as adjusting the angles of installation of the rotary stator vanes depending on the rotational speed. The GTE model has a modular structure. To determine the compressor parameters the modules for 1D or 2D flow calculation can be connected. As the initial data, besides the data traditionally specified in the 1st level GTE models it is necessary to set the geometrical parameters of the compressor flow path and blades on the medium radius (for the 2nd level GTE model) or along with the blade height (for the 3rd level). Both calculating compressor parameters methods are verified and have a fairly wide experience of practical use. The article presents the results of calculating the maps of the GTE multi-stage compressor using one- and two-dimensional approaches. Comparison of the compressor performances achieved by using of these two methods among themselves and with the experimental data has shown their good agreement. The approach used to simulate the flow in compressors makes it possible to estimate, by calculation, the surge margin, to consider the incidence angles and other flow parameters in the blade gaps in a wide range of GTE operation modes. Such results, as well as a comparison with experimental data, are presented in the article. The article also demonstrates the results of applying the described above model to the gas turbine engine performances calculation. The engine has the 12-stage axial compressor with the stator blades position of the first stages regulation. The calculated line of joint operation modes of the gas generator units, the dependence of the power and specific fuel consumption on the rotational speed. Presented are the processes in GTE on stationary modes analyzing results given in the article showed the used model advantage, reliability and expediency of its practical application.

scholarly journals A Comparison of Zero and One Equation Turbulence Modelling for Turbomachinery Calculations

1990 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Experimental Data ◽  
Transport Equation ◽  
Turbulence Model ◽  
Axial Compressor ◽  
Compressor Blade ◽  
Mixing Length ◽  
Equation Approach ◽  
Flow Development ◽  
Standard Models

The aim of this paper is to compare viscous predictions for two turbomachinery geometries performed with a simple mixing length turbulence model and a more advanced transport equation approach. The mixing length approach is simple and crude, but cheap; more sophisticated transport schemes are more physical but more expensive. This paper compares the performance of two standard models, in one host code, with experimental data for axial turbine secondary flow development and for axial compressor blade loss-incidence variation. Although the more sophisticated turbulence model does produce detail improvements in the quality of the predictions, as far as loss generation is concerned it is concluded there is little difference between the two models. The reasons for this are discussed in some detail.

Modal Analysis of the Axial Compressor Blade: Advanced Time-Dependent Electronic Interferometry and Finite Element Method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mykhaylo Tkach ◽  
Serhii Morhun ◽  
Yuri Zolotoy ◽  
Irina Zhuk
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Finite Element ◽  
High Reliability ◽  
Axial Compressor ◽  
Time Dependent ◽  
Experimental Setup ◽  
Vibration Modes ◽  
Compressor Blades ◽  
Isoparametric Finite Element

AbstractNatural frequencies and vibration modes of axial compressor blades are investigated. A refined mathematical model based on the usage of an eight-nodal curvilinear isoparametric finite element was applied. The verification of the model is carried out by finding the frequencies and vibration modes of a smooth cylindrical shell and comparing them with experimental data. A high-precision experimental setup based on an advanced method of time-dependent electronic interferometry was developed for this aim. Thus, the objective of the study is to verify the adequacy of the refined mathematical model by means of the advanced time-dependent electronic interferometry experimental method. The divergence of the results of frequency measurements between numerical calculations and experimental data does not exceed 5 % that indicates the adequacy and high reliability of the developed mathematical model. The developed mathematical model and experimental setup can be used later in the study of blades with more complex geometric and strength characteristics or in cases when the real boundary conditions or mechanical characteristics of material are uncertain.

Experimental Investigation Into the Effects of the Steady Wake-Tip Clearance Vortex Interaction in a Compressor Cascade

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Andreas Krug ◽  
Peter Busse ◽  
Konrad Vogeler
Keyword(s):  
Flow Field ◽  
Experimental Studies ◽  
Axial Compressor ◽  
Field Measurements ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Unsteady Interaction ◽  
Linear Compressor Cascade ◽  
Tip Clearance Vortex ◽  
The Impact

An important aspect of the aerodynamic flow field in the tip region of axial compressor rotors is the unsteady interaction between the tip clearance vortex (TCV) and the incoming stator wakes. In order to gain an improved understanding of the mechanics involved, systematic studies need to be performed. As a first step toward the characterization of the dynamic effects caused by the relative movement of the blade rows, the impact of a stationary wake-induced inlet disturbance on a linear compressor cascade with tip clearance will be analyzed. The wakes were generated by a fixed grid of cylindrical bars with variable pitch being placed at discrete pitchwise positions. This paper focuses on experimental studies conducted at the newly designed low-speed cascade wind tunnel in Dresden. The general tunnel configuration and details on the specific cascade setup will be presented. Steady state flow field measurements were carried out using five-hole probe traverses up- and downstream of the cascade and accompanied by static wall pressure readings. 2D-particle image velocimetry (PIV) measurements complemented these results by visualizing the blade-to-blade flow field. Hence, the structure of the evolving secondary flow system is evaluated and compared for all tested configurations.

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