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A Preliminary Design Tool for Radial Compressors

Schiff, Johannes (2013) In ISRN LUTMDN/TMHP--13/5287--SE
Department of Energy Sciences
Abstract
The aim of this thesis has been to implement a computer program capable of modelling
radial compressors. The work was conducted at the Division of Thermal Power Engineering,
Department of Energy Sciences at the Faculty of Engineering, Lund University.
With such a large field as radial compressors, some decomposition of the subject was
necessary. This thesis focuses on modelling the impeller and diffuser of the compressor, where
the components are individually studied. By doing this division between different parts of the
compressor, the individual components can be designed in isolation. If, for instance, only a
vaned diffuser is to be designed, no impeller design must first be found.
The resulting computer program called LURC... (More)
The aim of this thesis has been to implement a computer program capable of modelling
radial compressors. The work was conducted at the Division of Thermal Power Engineering,
Department of Energy Sciences at the Faculty of Engineering, Lund University.
With such a large field as radial compressors, some decomposition of the subject was
necessary. This thesis focuses on modelling the impeller and diffuser of the compressor, where
the components are individually studied. By doing this division between different parts of the
compressor, the individual components can be designed in isolation. If, for instance, only a
vaned diffuser is to be designed, no impeller design must first be found.
The resulting computer program called LURC (Lund University Radial Compressor) have
two different design tools for the impeller, one in-depth impeller flow analysis, one vaneless
diffuser design tool and one vaned diffuser design tool. The compressor designer can easily
perform different analyses with LURC, all design tools being easily accessible at all times. Also,
several of the different analysis tools are interconnected, allowing easy data exchange.
The so-called preliminary impeller design tool requires minimum input data from the
user, quickly yielding a promising impeller design. It is a one-dimensional analysis method,
where most parameters are specified on the mean streamline. The complete impeller geometry
is directly generated, making it a perfect tool for the non-experienced compressor designer.
Further, the result can be used as input data in any of the two diffuser analyses.
In the detailed impeller design tool more input data must be specified. Also, the geometry
and blade shapes are under full control of the designer. This analysis is also one-dimensional
but has the capability of creating three-dimensional impeller geometries. Such a tool is well
suited to the more experienced designer, knowing what he or she want to achieve. The result
can be used in both diffuser analyses, but also in the in-depth impeller flow analysis.
The in-depth impeller flow analysis is based on a quasi three-dimensional calculation
method. In this case a streamline curvature method is coupled with a stream function flow
analysis, allowing the three-dimensional problem to be composed of two two-dimensional ones.
From this analysis tool the velocity distributions along the blades may be found, giving the
experienced designer a vital piece of information.
Vaneless diffusers are very common in radial compressors, making it important to incorporate
these in LURC. Input data may be entered manually or imported from a previous impeller
analysis. The analysis is based on one-dimensional theory, including effects of wall friction. The
complete geometry is generated and the key results, such as discharge pressure and velocity,
are calculated.
The vaned diffuser design tool are focused on channel diffusers of the wedge type. Also
included in the analysis are the vaneless space right after the impeller discharge. As was the
case for the vaneless diffuser design tool, inlet data can be entered either manually or fetched
from an impeller analysis conducted earlier. The whole diffuser geometry is generated, that is,
both the vaneless space and the channel diffuser part. One-dimensional compressible channel
flow is the basis for this analysis.
LURC fulfils its main objective; being a fast design tool for establishing promising compressor
stage designs. Although mainly based on one-dimensional analyses, it is a very efficient and
powerful tool for determining important design parameters in a timely fashion. (Less)
Please use this url to cite or link to this publication:
author
Schiff, Johannes
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
Design Tool, Radial Compressors, design system, LURC
publication/series
ISRN LUTMDN/TMHP--13/5287--SE
report number
5287
ISSN
0282-1990
language
English
id
3920451
date added to LUP
2013-07-10 11:13:58
date last changed
2013-07-10 11:13:58
@misc{3920451,
  abstract     = {The aim of this thesis has been to implement a computer program capable of modelling
radial compressors. The work was conducted at the Division of Thermal Power Engineering,
Department of Energy Sciences at the Faculty of Engineering, Lund University.
With such a large field as radial compressors, some decomposition of the subject was
necessary. This thesis focuses on modelling the impeller and diffuser of the compressor, where
the components are individually studied. By doing this division between different parts of the
compressor, the individual components can be designed in isolation. If, for instance, only a
vaned diffuser is to be designed, no impeller design must first be found.
The resulting computer program called LURC (Lund University Radial Compressor) have
two different design tools for the impeller, one in-depth impeller flow analysis, one vaneless
diffuser design tool and one vaned diffuser design tool. The compressor designer can easily
perform different analyses with LURC, all design tools being easily accessible at all times. Also,
several of the different analysis tools are interconnected, allowing easy data exchange.
The so-called preliminary impeller design tool requires minimum input data from the
user, quickly yielding a promising impeller design. It is a one-dimensional analysis method,
where most parameters are specified on the mean streamline. The complete impeller geometry
is directly generated, making it a perfect tool for the non-experienced compressor designer.
Further, the result can be used as input data in any of the two diffuser analyses.
In the detailed impeller design tool more input data must be specified. Also, the geometry
and blade shapes are under full control of the designer. This analysis is also one-dimensional
but has the capability of creating three-dimensional impeller geometries. Such a tool is well
suited to the more experienced designer, knowing what he or she want to achieve. The result
can be used in both diffuser analyses, but also in the in-depth impeller flow analysis.
The in-depth impeller flow analysis is based on a quasi three-dimensional calculation
method. In this case a streamline curvature method is coupled with a stream function flow
analysis, allowing the three-dimensional problem to be composed of two two-dimensional ones.
From this analysis tool the velocity distributions along the blades may be found, giving the
experienced designer a vital piece of information.
Vaneless diffusers are very common in radial compressors, making it important to incorporate
these in LURC. Input data may be entered manually or imported from a previous impeller
analysis. The analysis is based on one-dimensional theory, including effects of wall friction. The
complete geometry is generated and the key results, such as discharge pressure and velocity,
are calculated.
The vaned diffuser design tool are focused on channel diffusers of the wedge type. Also
included in the analysis are the vaneless space right after the impeller discharge. As was the
case for the vaneless diffuser design tool, inlet data can be entered either manually or fetched
from an impeller analysis conducted earlier. The whole diffuser geometry is generated, that is,
both the vaneless space and the channel diffuser part. One-dimensional compressible channel
flow is the basis for this analysis.
LURC fulfils its main objective; being a fast design tool for establishing promising compressor
stage designs. Although mainly based on one-dimensional analyses, it is a very efficient and
powerful tool for determining important design parameters in a timely fashion.},
  author       = {Schiff, Johannes},
  issn         = {0282-1990},
  keyword      = {Design Tool,Radial Compressors,design system,LURC},
  language     = {eng},
  note         = {Student Paper},
  series       = {ISRN LUTMDN/TMHP--13/5287--SE},
  title        = {A Preliminary Design Tool for Radial Compressors},
  year         = {2013},
}