CFD-Based Throughflow Solver in a Turbomachinery Design System

2007 ◽  
Author(s):  
Fahua Gu ◽  
Mark R. Anderson
Keyword(s):  
Three Dimensional ◽  
Design System ◽  
Flow Angle ◽  
Stream Surface ◽  
Streamline Curvature ◽  
Machine Performance ◽  
Multi Stage ◽  
Pros And Cons ◽  
Turbomachinery Design ◽  
Different Levels

Throughflow analysis is a critical component for the multi-stage axial turbomachine design. The Euler throughflow approach has been developed over the last couple of decades, but has been less successful than its early peer, the streamline curvature approach. In this paper an Euler throughflow approach is described for engineering applications. It includes the steps needed to construct the stream surface, such as modifications for the incidence and deviation, and the throat area correction. The flow angle difference at the trailing edge and in the downstream non-bladed gap stations is resolved, and the numerical loss from solving the Euler equation is removed as well. This solver has been integrated into a comprehensive turbomachinery design system. It creates and modifies the machine geometries and predicts the machine performance at different levels of approximation, including one-dimensional design and analysis, quasi-three-dimensional methods (blade-to-blade and throughflow) and full-three-dimensional steady-state CFD analysis. The flow injection and extraction functions are described, as is the implementation of the radial mass distribution. Some discussion is dedicated to the shock calculation. Finally, examples are provided to demonstrate the pros and cons of the Euler throughflow approach and also to demonstrate the potential to solve for a wider range of flow conditions, particularly choked and transonic flows that limit stream function based solvers.

Multall—An Open Source, Computational Fluid Dynamics Based, Turbomachinery Design System

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
John D. Denton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design System ◽  
Input File ◽  
Stream Surface ◽  
Source Codes ◽  
Overall Performance ◽  
Complex Features ◽  
Turbomachinery Design

Turbomachinery design systems are usually the jealously guarded property of large companies, and the author is not aware of any for which the source code is freely available. This paper is aimed providing a freely available system that can be used by individuals or small companies who do not have access to an in-house system. The design system is based on the three-dimensional (3D) computational fluid dynamics (CFD) solver Multall, which has been developed over many years. Multall can obtain solutions for individual blade rows or for multistage machines, and it can also perform quasi-3D (Q3D) blade-to-blade calculations on a prescribed stream surface and axisymmetric throughflow calculations. Multall is combined with a one-dimensional (1D) mean-line program, Meangen, which predicts the blading parameters on a mean stream surface and writes an input file for Stagen. Stagen is a blade geometry generation and manipulation program which generates and stacks the blading, combines it into stages, and writes an input file for Multall. The system can be used to design the main blade path of all types of turbomachines. Although it cannot design complex features such as shroud seals and individual cooling holes, these features can be modeled, and their effect on overall performance predicted. The system is intended to be as simple and easy to use as possible, and the solver is also very fast compared to most CFD codes. A great deal of user experience ensures that the overall performance is reasonably well predicted for a wide variety of machines. This paper describes the system in outline and gives an example of its use. The source codes are written in FORTRAN77 and are freely available for other users to try.

Viscous Throughflow Modelling for Multi-Stage Compressor Design

1992 ◽  
Author(s):  
M. A. Howard ◽  
S. J. Gallimore
Keyword(s):  
Shear Force ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design System ◽  
Flow Angle ◽  
Axial Compressors ◽  
Multi Stage ◽  
Viscous Shear ◽  
Compressor Design

An existing throughflow method for axial compressors, which accounts for the effects of spanwise mixing using a turbulent diffusion model, has been extended to include the viscous shear force on the endwall. The use of a shear force, consistent with a no-slip condition, on the annulus walls in the throughflow calculations allows realistic predictions of the velocity and flow angle profiles near the endwalls. The annulus wall boundary layers are therefore incorporated directly in the throughflow prediction. This eliminates the need for empirical blockage factors or independent annulus boundary layer calculations. The axisymmetric prediction can be further refined by specifying realistic spanwise variations of loss coefficient and deviation to model the three-dimensional endwall effects. The resulting throughflow calculation gives realistic predictions of flow properties across the whole span of a compressor. This is confirmed by comparison with measured data from both low and high speed multi-stage machines. The viscous throughflow method has been incorporated into an axial compressor design system. The method predicts the meridional velocity defects in the endwall region and consequently blading can be designed which allows for the increased incidence, and low dynamic head, near to the annulus walls.

scholarly journals Numerical Investigations on the Optimum Design of Return Channels of Multi-Stage Centrifugal Compressors

1999 ◽  
Author(s):  
L. J. Lenke ◽  
H. Simon
Keyword(s):  
Flow Structure ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Secondary Flows ◽  
Load Range ◽  
Flow Angle ◽  
Numerical Investigations ◽  
Streamline Curvature ◽  
Multi Stage ◽  
Return Channel

Numerical simulations of the flow within return channels for the aerodynamic design are presented. The investigated return channels are typical to join the exit from one stage of a centrifugal machine to the inlet of the next stage and cover the range of high flow coefficients. Due to the strongly three-dimensional flow structure with high streamline curvature and secondary flows on hub and shroud of the return channel vanes, a modified explicit algebraic Reynolds stress model will be used. Starting with a comparison between measurements and numerical results to demonstrate the performance of the turbulence model in the prediction of losses, exit flow angle and separation behavior, further numerical investigations with different variations of the geometry of the channel will be considered. 3-D turbulent calculations at the design point and part load range show the influence of the design especially of the crossover bend onto the flow structure.

Multall: An Open Source, CFD Based, Turbomachinery Design System

2017 ◽  
Author(s):  
John D. Denton
Keyword(s):  
Design System ◽  
Small Companies ◽  
Input File ◽  
Stream Surface ◽  
Source Codes ◽  
Multi Stage ◽  
Design Systems ◽  
Overall Performance ◽  
Complex Features ◽  
Turbomachinery Design

Turbomachinery design systems are usually the jealously guarded property of large companies, the author is not aware of any for which the source code is freely available. The present paper is aimed providing a freely available system that can be used by individuals or small companies who do not have access to an in-house system. The design system is based on the 3D CFD solver Multall, which has been developed over many years. Multall can obtain solutions for individual blade rows or for multi-stage machines, it can also perform quasi-3D blade-to-blade calculations on a prescribed stream surface and axisymmetric throughflow calculations. Multall is combined with a one-dimensional mean-line program, Meangen, which predicts the blading parameters on a mean stream surface and writes an input file for Stagen. Stagen is a blade geometry generation and manipulation program which generates and stacks the blading, combines it into stages, and writes an input file for Multall. The system can be used to design the main blade path of all types of turbomachines. Although it cannot design complex features such as shroud seals and individual cooling holes these features can be modeled and their effect on overall performance predicted. The system is intended to be as simple and easy to use as possible and the solver is also very fast compared to most CFD codes. A great deal of user experience ensures that the overall performance is reasonably well predicted for a wide variety of machines. This paper describes the system in outline and gives an example of its use. The source codes are written in FORTRAN77 and are freely available for other users to try.

Inverse Design of 3D Multi-Stage Transonic Fans at Dual Operating Points

2013 ◽  
Author(s):  
James H. Page ◽  
Paul Hield ◽  
Paul G. Tucker
Keyword(s):  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Inverse Design ◽  
Flow Angle ◽  
Trade Offs ◽  
Multi Stage ◽  
Full Speed ◽  
Computational Fluid Dynamics Cfd ◽  
Operating Points

Semi-inverse design is the automatic re-cambering of an aerofoil, during a computational fluid dynamics (CFD) calculation, in order to achieve a target lift distribution while maintaining thickness, hence “semi-inverse”. In this design method, the streamwise distribution of curvature is replaced by a stream-wise distribution of lift. The authors have developed an inverse design code based on the method of Hield (2008) which can rapidly design three-dimensional fan blades in a multi-stage environment. The algorithm uses an inner loop to design to radially varying target lift distributions, an outer loop to achieve radial distributions of stage pressure ratio and exit flow angle, and a choked nozzle to set design mass flow. The code is easily wrapped around any CFD solver. In this paper, we describe a novel algorithm for designing simultaneously for specified performance at full speed and peak efficiency at part speed, without trade-offs between the targets at each of the two operating points. We also introduce a novel adaptive target lift distribution which automatically develops discontinuous changes of calculated magnitude, based on the passage shock, eliminating erroneous lift demands in the shock vicinity and maintaining a smooth aerofoil.

A Reynolds-Averaged Navier-Stokes Solver in a Turbomachinery Design System

2007 ◽  
Author(s):  
Fahua Gu ◽  
Mark R. Anderson
Keyword(s):  
Turbulence Model ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Integrated Design ◽  
Navier Stokes ◽  
Design System ◽  
Navier Stokes Equations ◽  
Wall Functions ◽  
Machine Performance ◽  
Reynolds Averaged Navier Stokes

The design of turbomachinery has been focusing on the improvement of the machine efficiency and the reduction of the design cost. This paper presents an integrated design system to create the machine geometry and to predict the machine performance at different levels of approximation, including one-dimensional design and analysis, quasi-three-dimensional-(blade-to-blade, throughflow) and full-three-dimensional-steady-state CFD analysis. One of the most important components, the Reynolds-averaged Navier-Stokes solver, is described in detail. It originated from the Dawes solver with numerous enhancements. They include the use of the low speed pre-conditioned full Navier-Stokes equations, the addition of the Spalart-Allmaras turbulence model and an improvement of wall functions related with the turbulence model. The latest upwind scheme, AUSM, has been implemented too. The Dawes code has been rewritten into a multi-block solver for O, C, and H grids. This paper provides some examples to evaluate the effect of grid topology on the machine performance prediction.

The Importance of Circumferential Non-uniformities in a Passage-Averaged Quasi-Three-Dimensional Turbomachinery Design System

1986 ◽  
Vol 108 (2) ◽  
pp. 240-245 ◽  
Author(s):  
I. K. Jennions ◽  
P. Stow
Keyword(s):  
Pressure Gradient ◽  
Guide Vane ◽  
Three Dimensional ◽  
Radial Pressure ◽  
Turbine Rotor ◽  
Design System ◽  
Radial Pressure Gradient ◽  
Flow Effects ◽  
Nozzle Guide ◽  
Turbomachinery Design

The purpose of this paper is to show, for both rotating and non-rotating blade rows, the importance of including circumferential non-uniform flow effects in a quasi-three-dimensional blade design system. The paper follows from previous publications on the system in which the mathematical analysis and computerized system are detailed. Results are presented for a different stack of the nozzle guide vane presented previously and for a turbine rotor. In the former case it is again found that the blade force represents a major contribution to the radial pressure gradient, while for the rotor the radial pressure gradient is dominated by centrifugal effects. In both examples the effects of circumferential non-uniformities are detailed and discussed.

A Quasi-Three-Dimensional Turbomachinery Blade Design System: Part I—Throughflow Analysis

1985 ◽  
Vol 107 (2) ◽  
pp. 301-307 ◽  
Author(s):  
I. K. Jennions ◽  
P. Stow
Keyword(s):  
Three Dimensional ◽  
Computing System ◽  
Design System ◽  
Blade Design ◽  
Weighted Averages ◽  
Streamline Curvature ◽  
Blade Row ◽  
Blade Section ◽  
System Part ◽  
Analysis System

The purpose of this work has been to develop a quasi-three-dimensional blade design and analysis system incorporating fully linked throughflow, blade-to-blade and blade section stacking programs. In Part I of the paper, the throughflow analysis is developed. This is based on a rigorous passage averaging technique to derive throughflow equations valid inside a blade row. The advantages of this approach are that the meridional streamsurface does not have to be of a prescribed shape, and by introducing density weighted averages the continuity equation is of an exact form. Included in the equations are the effects of blade blockage, blade forces, blade-to-blade variations and loss. The solution of the equations is developed for the well-known streamline curvature method, and the contributions from these extra effects on the radial equilibrium equation are discussed. Part II of the paper incorporates the analysis into a quasi-three-dimensional computing system and demonstrates its operational feasibility.

Application and Validation of CFD in a Turbomachinery Design System

2003 ◽  
Author(s):  
Mark R. Anderson ◽  
Fahua Gu ◽  
Paul D. MacLeod
Keyword(s):  
High Performance ◽  
Fluid Dynamic ◽  
Detailed Comparison ◽  
Design System ◽  
Flow Solver ◽  
Streamline Curvature ◽  
Wide Range ◽  
Analysis System ◽  
Pressure Changes ◽  
Turbomachinery Design

CFD (Computational Fluid Dynamics) has enjoyed widespread use in the turbomachinery industry for some time. When coupled with other solvers, such as meanline and streamline curvature, it can be an integral part of a comprehensive design and analysis system. The pbCFD (Pushbutton CFD®) product is the CFD component of Concepts NREC’s Agile Engineering Design System®. It is a structured grid CFD flow solver optimized for turbomachinery analysis. Concepts NREC has made an extensive validation effort over a wide range of diverse turbomachinery stages including, compressors, pumps, and turbines for both radial and axial machines. Detailed comparison to test data of 10 different stages is shown in this paper and clearly demonstrates the high performance of pbCFD in quantifying fluid dynamic losses and pressure changes over a wide range of geometries and flow conditions.

Viscous Throughflow Modeling for Multistage Compressor Design

1993 ◽  
Vol 115 (2) ◽  
pp. 296-304 ◽  
Author(s):  
M. A. Howard ◽  
S. J. Gallimore
Keyword(s):  
Shear Force ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design System ◽  
Flow Angle ◽  
Axial Compressors ◽  
Dynamic Head ◽  
Viscous Shear ◽  
Compressor Design

An existing throughflow method for axial compressors, which accounts for the effects of spanwise mixing using a turbulent diffusion model, has been extended to include the viscous shear force on the endwall. The use of a shear force, consistent with a no-slip condition, on the annulus walls in the throughflow calculations allows realistic predictions of the velocity and flow angle profiles near the endwalls. The annulus wall boundary layers are therefore incorporated directly into the throughflow prediction. This eliminates the need for empirical blockage factors or independent annulus boundary layer calculations. The axisymmetric prediction can be further refined by specifying realistic spanwise variations of loss coefficient and deviation to model the three-dimensional endwall effects. The resulting throughflow calculation gives realistic predictions of flow properties across the whole span of a compressor. This is confirmed by comparison with measured data from both low and high-speed multistage machines. The viscous throughflow method has been incorporated into an axial compressor design system. The method predicts the meridional velocity defects in the endwall region and consequently blading can be designed that allows for the increased incidence, and low dynamic head, near the annulus walls.

Sign in / Sign up

Export Citation Format

Share Document