Semi-Inverse Design Applied to an Eight Stage Transonic Axial Flow Compressor

2008 ◽  
Author(s):  
Paul Hield
Keyword(s):  
Thickness Distribution ◽  
Axial Flow ◽  
Direct Analysis ◽  
Current Approach ◽  
Three Dimensions ◽  
Inverse Design ◽  
System Level ◽  
Design Intent ◽  
Axial Flow Compressor ◽  
Flow Compressor

Semi-Inverse Design is a class of Computational Fluid Dynamics (CFD) procedures for calculating aerofoil geometry from prescriptions of pressure loading and thickness distribution; when describing an aerofoil in three dimensions a stacking axis is also needed. All sixteen blade rows of an eight stage transonic axial flow compressor have been simultaneously designed in a single inverse 3D CFD calculation. The tip Mach number of the first rotor was just over sonic with a peak value in excess of 1.25. Apart from the substitution of geometric by aerodynamic aerofoil boundary conditions, the CFD model is the same as that used for direct analysis and includes rotor and stator clearance gaps as well as stator shroud leakage flows. This has profound implications for 3D CFD in the context of the total design process at a system level. The technique allows 3D CFD to behave like a design point through flow in the sense that we can now ask the question of 3D CFD - “what is the performance of a turbo-machine that has this design intent?” as opposed to “does this set of aerofoils meet the design intent and if they do what is its performance? And if they do not how should they be changed?” Inverse design provides a means of conveying design intent up through the “fidelity levels” from 1-D and 2-D, through Low Fidelity 3D CFD to High Fidelity CFD. Thus the desired loading distribution may be determined cheaply using 2D blade to blade analysis, either by iterative direct analysis (the current approach) or using a semi-inverse technique in 2D. As an illustration of this, a 1-D tool will be presented which produces estimates of aerofoil shape and surface velocities in real time to enable the designer to manipulate the loading distributions which are then used in Inverse 3D CFD to realize the final geometry.

Inverse Design of Axial-Flow Compressor Blades Using Elastic Surface Algorithm in Subsonic and Transonic Flow Regimes With Separation

2016 ◽  
Author(s):  
M. H. Noorsalehi ◽  
M. Nili-Ahamadabadi ◽  
E. Shirani ◽  
M. Safari
Keyword(s):  
Pressure Distribution ◽  
Transonic Flow ◽  
Design Method ◽  
Axial Flow ◽  
Flow Regimes ◽  
Inverse Design ◽  
Elastic Surface ◽  
Axial Flow Compressor ◽  
Inverse Design Method ◽  
Flow Compressor

In this study, a new inverse design method called Elastic Surface Algorithm (ESA) is developed and enhanced for axial-flow compressor blade design in subsonic and transonic flow regimes with separation. ESA is a physically based iterative inverse design method that uses a 2D flow analysis code to estimate the pressure distribution on the solid structure, i.e. airfoil, and a 2D solid beam finite element code to calculate the deflections due to the difference between the calculated and target pressure distributions. In order to enhance the ESA, the wall shear stress distribution, besides pressure distribution, is applied to deflect the shape of the airfoil. The enhanced method is validated through the inverse design of the rotor blade of the first stage of an axial-flow compressor in transonic viscous flow regime. In addition, some design examples are presented to prove the effectiveness and robustness of the method. The results of this study show that the enhanced Elastic Surface Algorithm is an effective inverse design method in flow regimes with separation and normal shock.

Application of an Inverse Design Method to Meet a Target Pressure in Axial-Flow Compressors

2011 ◽  
Author(s):  
Ali Madadi ◽  
Mohammad Jafar Kermani ◽  
Mahdi Nili-Ahmadabadi
Keyword(s):  
Flow Field ◽  
Pressure Distribution ◽  
Axial Flow ◽  
Inverse Design ◽  
Design Algorithm ◽  
Axial Flow Compressor ◽  
Differential Movement ◽  
Target Pressure ◽  
Flow Compressor ◽  
Blade Geometry

Numerous methods have been developed to design axial-flow compressor blades. These methods are generally categorized into inverse or direct approaches. In the inverse design methods, a distribution of an aerodynamic parameter such as pressure or velocity on the blade surfaces is given, and the target blade geometry that can provide the corresponding distribution is to be determined. In the present work, a novel inverse design algorithm called Ball Spine Algorithm (BSA) is developed to design an axial-flow compressor on the blade to blade surface. In the BSA, the blade surfaces are considered as a set of virtual balls that move freely along the specified directions, called ‘spines’. At first, initial blade geometry is guessed and the blade-to-blade flow field is analyzed by an in-house inviscid flow solver based on the Roe scheme. Comparing the computed pressure distribution (CPD) on the blade surfaces with the target pressure distribution (TPD), gives a guideline in a differential movement for the balls to obtain a modified geometry. For the flow field analysis on the modified geometry, new grids are generated by a combined algebraic-elliptic code. The sequence is repeated until the target pressure is reached. For validation, the approach is applied on an arbitrary blade profile.

An Implicit Off-Design Deviation Angle Correlation of Axial Flow Compressor Blade Elements

2017 ◽  
Author(s):  
Wu Dong-run ◽  
Teng Jin-fang ◽  
Qiang Xiao-qing ◽  
Feng Jin-zhang
Keyword(s):  
Experimental Data ◽  
Incidence Angle ◽  
High Reliability ◽  
Axial Flow ◽  
Compressor Blade ◽  
Deviation Angle ◽  
Axial Flow Compressor ◽  
New Correlation ◽  
Classical Correlations ◽  
Flow Compressor

This paper applies a new analytical/empirical method to formulate the off-design deviation angle correlation of axial flow compressor blade elements. An implicit function of deviation angle is used to map off-design deviation curves into linear correlations (minimum linear correlation coefficient R = 0.959 in this paper). Solution of the coefficients in the correlation is given through the study of classical theories and statistical analysis of the experimental data. The off-design deviation angle can be calculated numerically. The approach requires only knowledge of the blade element geometry. The comparison among 2 classical correlations and the new correlation proposed in this paper shows the new correlation has minimum error over the entire range of incidence angle while classical correlations show high reliability only in a limited range. Experimental data in this paper is collected from NASA’s open technical reports. Rotors and stators are studied together. Considering there is significant deviation angle variation along spanwise direction, only data at 50% span is studied, if possible. The error among experimental data, statistical regressions of the experimental data, and numerical results based on the new correlation is discussed. It has to be noted that the influence of the flow condition other than incidence angle is only being discussed but with less break through.

The Development of an Aerodynamic Performance Prediction Tool for Modern Axial Flow Compressor Profiles

2006 ◽  
Author(s):  
Dario Bruna ◽  
Carlo Cravero ◽  
Mark G. Turner
Keyword(s):  
Performance Prediction ◽  
Parametric Design ◽  
Flow Analysis ◽  
Axial Flow ◽  
Navier Stokes ◽  
Flow Angle ◽  
Flow Solver ◽  
Aerodynamic Loss ◽  
Axial Flow Compressor ◽  
Flow Compressor

The development of a computational tool (MP-LOS) for the aerodynamic loss modeling and prediction for axial-flow compressor blade sections is presented in this paper. A state-of-the-art quasi 3-D flow solver, MISES, has been used for the flow analysis on existing airfoil geometries in many working conditions. Different values of inlet flow angle, inlet Mach number, AVDR, Reynolds number and solidity have been chosen to investigate a possible working range. The target is a loss prediction formulation that will be introduced into throughflow or axisymmetric Navier-Stokes codes for the performance prediction of multistage axial flow compressors. The loss coefficient has been correlated to the flow parameters that have shown an influence on the profile loss for the blades under study. The proposed correlation, using the described computational approach, can be extended to any profile family with the aid of any code for the parametric design of blade profiles.

Aspirating Probe Measurements of the Unsteady Total Temperature Field Downstream of an Embedded Stator in a Multistage Axial Flow Compressor

1996 ◽  
Author(s):  
N. Suryavamshi ◽  
B. Lakshminarayana ◽  
J. Prato
Keyword(s):  
Axial Flow ◽  
Pressure Data ◽  
Peak Efficiency ◽  
Axial Flow Compressor ◽  
Composite Flow ◽  
Total Temperature ◽  
Temperature And Pressure ◽  
Flow Compressor ◽  
Isentropic Efficiency ◽  
Probe Measurements

The results from the area traverse measurements of the unsteady total temperature using a high response aspirating probe downstream of the second stator of a three stage axial flow compressor are presented. The measurements were conducted at the peak efficiency operating point. The unsteady total temperature data is resolved into deterministic and unresolved components. Hub and casing regions have high levels of unsteadiness and consequently high levels of mixing. These regions have significant levels of shaft resolved and unresolved unsteadiness. Comparisons are made between the total temperature and the total pressure data to examine the rotor 2 wake characteristics and the temporal variation of the stator exit flow. Isentropic efficiency calculations at the midpitch location show that there is about a 4% change in the algebraically averaged efficiency across the blades of the second rotor and if all the rotor 2 blades were behaving as a “best” blade, the improvement in efficiency would be about 1.3%. An attempt is made to create a composite flow field picture by correlating the unsteady velocity data with temperature and pressure data.

scholarly journals Computation of Secondary Flows in an Axial Flow Compressor Including Inviscid and Viscous Flow Computation

1984 ◽  
Author(s):  
Francis Leboeuf
Keyword(s):  
Boundary Layer ◽  
Viscous Flow ◽  
Axial Flow ◽  
Inviscid Flow ◽  
Secondary Flows ◽  
Computational Method ◽  
Flow Computation ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Highly Loaded

A computational method for secondary flows in a compressor has been extended to treat stalled flows. An integral equation is used which simulates the inviscid flow at the wall, under the viscous flow influence. We present comparisons with experimental results for a 2D stalled boundary layer, and for the secondary flow in a highly loaded stator of an axial flow compressor.

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