School
of Engineering and Mathematical Sciences
COMPUTATIONAL FLUID DYNAMICS IN City University, London,
7-8 September 2013 Organised prior to the 8th
International Conference on Compressors and Their Systems, City University, London, 9-10
September 2013 |
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Outline
The University will present the second series of courses on compressor technology with emphasis on screw compressors. This course is dedicated to advanced topics in application of CFD to rotary positive displacement machines for industrial use and research. Topics to be covered include: grid generation for complex geometries, advances in CFD methods, turbulence modelling and validation of CFD performance prediction, Integration with CAD and Industrial applications. It will be delivered by the leading experts in CFD, vendors of CFD codes, academics and industrial users. The course and forum will take place at the Northampton Square site of City University London prior to the 8th Conference on Compressors and their Systems on Saturday 7th and Sunday 8th September 2013. The course will be delivered in 6 sessions which last 1hr and 30 minutes each. Each block will consist of 1 to 3 lectures. Three blocks will be delivered on each day of the course. The discussion forum will take place at the end of each day in order to address the issues identified during the course. |
Express interest to attend & Register |
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Objectives
1)
To provide forum for discussion wide range of issues on CFD in
positive displacement machines. 2)
To hear about latest developments in this area from world leading
experts 3)
To enable industry and academia meet with CFD and Grid generation
vendors 4)
To provide directions for future developments in CFD for positive
displacement machines Program
Saturday, 7th September 9,00-16,00 0900- 0905 Welcome and Introduction 0905-1045 Session 1: General CFD
with emphasis on modelling positive displacement machines, by Prof Milovan Peric – CD-adapco, Germany 1045-1100 Coffee break 1100-1230 Session 2: Grid generation theory and practice 1)
Grid
generation and CFD analysis in Screw Compressors 2) ANSA and META for pre and post processing of
industrial applications 1230-1330 Lunch 1330-15000 Session 3: Available CFD codes, theory and practice 1) Use of Ansys CFX and Fluent for analysis of positive
displacement machines by Mike Chudiak - Ansys, Canada 2) Application of full 3D
and 1D/3D modelling in IC engines by Dr Vlado Przulj, Ricardo, Nick Tiney –
Ricardo, UK 1500-1515 Coffee break 1515-1600 Forum 1: CFD and Grid Generation Sunday, 8th September 9,30-16,45 0930-1100 Session 4: Application
of CFD in other Positive displacement machines 1)
PumpLinx: Virtual Testing of Fluid Pumps, Motors, Compressors, Valves and
Systems by Sam Lawry and Jiang Yu - Simerics,
USA 2)
Application of CFD in piston compressors 1100-1115 Coffee break 1115-1245 Session
5:
Industrial application of CFD in screw compressors 1) Jack Sauls,
Scott Branch - Trane, Ingersoll Rand,
USA 2)
Dr Maria Pascu -
Howden Compressors Ltd, Glasgow UK 1245-1400 Lunch 1400-1530 Session 6: Future CFD developments in positive displacement compressors 1) Recent developments in
grid generation for Screw Compressors by Mr. Sham Rane -
City University London, UK 2)
Opportunities for modelling multiphase flows in positive displacement
machines 1530-1545 Coffee 1545-1645 Forum 2: Future of CFD in positive displacement compressors 1800-2000 8th International
Conference on Compressors and their Systems
–
Reception and Early Registration Lecturers
Prof
Milovan Peric - CD-adapco, Germany
Positive displacement machines are characterized by
moving parts, so the main feature of a CFD method applicable to such machines
is the ability to account for various motion patterns. Finite volume methods
commonly employed in CFD codes are well suited for moving and deforming
boundaries, provided that the space conservation law is properly accounted
for in the discretized equations. The main challenge is simulating flows in
positive displacement machines lies in accounting for grid motion and its
adaptation to moving walls, such that an acceptable grid quality is
maintained. In this lecture, conservation equations for
moving/deforming control volumes and their discretization using second-order
methods and arbitrary polyhedral control volumes will be presented first. Different
possibilities to account for motion of various parts (morphing of grids with
a constant topology, re-gridding, sliding of grid blocks attached to moving
and fixed parts along curved surfaces, overlapping grids etc.) will be
discussed next. Accounting for multiple phases (primarily liquids and gases)
and fluid-structure interaction will also be briefly addressed. Some examples
of application of STAR-CCM+ software to flows in various positive
displacement machines will be shown before trends for future development in
this area are introduced (overset grids, automatic local grid adaptation,
coupled simulation of flow, heat transfer and deformation of solid structures
etc.) and discussed. Prof. Ahmed Kovacevic - City University
London
Prof Kovacevic is Howden Chair Professor of
Engineering Design at City University in London. His main research interests
are in the integration of computer aided design for positive displacement
compressors, Computational Continuum Mechanics in positive displacement machines,
research and development of positive displacement compressors with the main
focus on screw compressors. As educator he is interested in engineering and
mechanical design principles, integration of design methods and tools by use
of computers and the international collaborative educational programme. Computational Fluid Dynamics (CFD) can be readily
used for the flow prediction and analysis of screw compressors. Several case
studies are presented here to show the scope and applicability of such
methods. These include solid-fluid interaction in screw compressors,
prediction of flow generated noise in screw machines, cavitation modelling in
gear pumps, and flow in multiphase pumps for oil and gas industry. Numerical
grids for all these cases were generated by us of an in-house grid generator
SCORG(C), while the CFD calculations were performed with a variety of
commercially available CFD codes. Dr Dimitris Soliotis - Beta
CAE Systems S.A. Greece
Dr Dimitris Souliotis works in Customers Service Department
responsible for CFD applications. Graduate of the Aristotle University of
Thessaloniki (AUTh), Department of Mechanical
Engineering. Dimitris holds a Ph.D
from AUTh. Dimitris is
participating in various International Conferences. The application of CFD in modern industrial design
and analysis has brought up a new field of development across a series of
processes and tools. The ability to model complex flow problems on
multicomponent assemblies has increased the need for automation in the model
pre and post processing. Furthermore the need for constant movement of such
models requires high level of automation and robustness in the meshing field. BETA CAE SYSTEMS S.A. has a long history in the
development of CFD pre and post processing multidisciplinary tools that
interface with an extended list of software in CAE. It has developed several
proprietary meshing tools and algorithms that respond to the needs of a
variety of applications and industries in the CFD field. Additionally all the
observed phenomena can be automatically processed and realized within the
multidisciplinary post processing environment of META. Within this context we will also emphasize on the
tools that will allow the generation of the positive displacement models
while interfacing with DISCO software. We will focus on the generation of
hybrid mesh in ANSA within an automated process that will produce all the
required girds for each time step. The whole process is based on high quality
surface representation that ensures the accuracy of the modelling and
consequently the accuracy of the simulation. A real time showcase of the grid
generation in ANSA will be carried out on a simplified design of a screw
compressor coupled with data provided by City University. Mr Mike Chudiak
– Ansys,Canada
Mr Chudiak is a Lead
Technical Specialist at ANSYS Inc.
Located in Waterloo, Canada, Mike manages a team of engineers in the
support and services function. He has
been involved with CFD since 1995, and has been at ANSYS for the past 12
years. The motion of positive displacement machines adds a
unique complication in the accurate modelling of their operation in fluid
dynamic calculations. The computational meshes need to dynamically adjust to
the movement of the machine parts. Changes to the geometry of the fluid-space
can be accounted for in the discretized representation of the volume through
various approaches, such as local/global re-meshing, cell layering, mesh
deformation, immersed solids, or a combination of multiple techniques. Each
method has a cost/benefit balance that needs to be taken into consideration.
The best approach for modelling one particular machine may not be optimal (or
even possible!) for another. In this presentation an overview of these techniques
and the functionality available in ANSYS CFX and ANSYS Fluent computational
fluid dynamic software tools is reviewed. Some example machine applications
and solutions will be discussed. Dr Vlado Przulj and Nick Tiney - Ricardo,
UK
Dr Przulj is a
Computational Fluid Dynamics professional with more than 20 years of wide
experience in mathematical modelling of fluid flows and heat transfer, the
algorithm development, associated solution methods and the code development.
He is a principal developer in Ricardo Software. Before joining Ricardo he
worked for AVL List where he contributed to the development of the AVL FIRE
CFD code. His CFD experience encompasses cell-centred, finite-volume pressure
based methods applicable to flows at all speeds as well as design of
multi-domain and multi-phase object oriented code architecture supporting
multi-physics simulations. VECTIS is a general purpose CFD tool extensively
used in engine design where in-cylinder simulations are performed to
investigate various phenomena such as fuelling effects, spray injector
positioning, piston shape and bowl design and the effects these have on
combustion and emissions. These simulations require comprehensive models for
fuel sprays and combustion as well as the deployment of moving grid
technology. Considering that a moving grid problem is the
generic one, this lecture provides a short theoretical background to moving
grids. The emphasis is on the dynamic grids which describe combined deforming
and topology modified grids. Topological changes can be introduced by
employing either topology modifiers (addition/removal of cell layers, sliding
interfaces, local re-meshing) or complete re-meshing. The latter approach is
implemented in the VECTIS solver where deforming grid steps using Laplacian smoothing are followed by complete domain
re–meshing. Other important elements of in-cylinder simulations such as
geometry and grid setup, definition of motion for the valves and piston,
strategy and control of in-cylinder events, and resolution of issues
associated with opening/closing of the intake and exhaust valves, are also
discussed. The results of 1D WAVE code simulations are typically used as
initial conditions in the ports and combustion chamber. Practical demonstration of a typical in-cylinder
simulation is also planned. The demonstration will involve preparation of a
run strategy, import of the CAD geometry, generation of multiple grid files,
definition of moving boundaries and their motion, and presentation of the
selected results. Dr Sam Lawry - Simerics,
USAil
Dr. Lowry has served as President of Simerics, Inc. since its founding in 2005. He received an
A.B. in Engineering and Applied Physics from Harvard College, an M.S. in
Mechanical Engineering from Case Western Reserve University and a Ph.D. in
Engineering Sciences from the University of Tennessee Space Institute. Dr. Lowry's prior work experience includes more than 10
years at CFD Research Corporation, concluding as Director of Advanced
Technology, and five years as a NASA engineer in the Turbomachinery
Branch at the Marshall Space Flight Center.. Computer simulations of pumps and compressors can
now serve the same function as hardware testing. These simulations can be
done in less time with less cost while providing engineering data of similar
quality as experiments. Furthermore, computer modeling
can be performed directly by the engineer doing the hardware design, thus
providing a tight link between analysis and design optimization. Virtual
testing can also be used to analyze problems with
existing hardware, either as standalone components or in the context of a
system. This presentation focuses on PumpLinx, a
Computational Fluid Dynamics (CFD) tool that serves as a virtual test bed. PumpLinx predicts the performance of pumps and
compressors in terms of head rise, power, efficiency, cavitation effects,
noise, and/or damage. PumpLinx starts with existing
designs created in a third party CAD package. Once the geometry is imported,
the pump is meshed, modeled, simulated and analyzed, all in a single interface. Various operating
conditions and fluid properties can be input to simulate the pump or
compressor over a range of operating conditions. The output is similar to
what would be measured for a fully instrumented test, with additional flow
visualization and integrated quantities. This presentation will provide
selected examples of the simulation of compressors and pumps. Prof Cesar J. Deschamps
- Federal University of St.Catarina - Brasil
Prof. Deschamps
received his Ph.D. degree in Mechanical Engineering from the University of
Manchester, UK, in 1994. He is currently Associate Professor of Mechanical Engineering
at the Federal University of Santa Catarina,
Brazil, where he has taught courses on Fluid Mechanics, Turbulent Flow and
Compressor Thermodynamics. His research interests includes
refrigeration compressors, with emphasis on automatic valves and thermal
management, as well as turbulent flow and aeroacoustics. Reciprocating compressors are commonly used in
refrigeration systems and can be manufactured economically in a wide range of
sizes. The design of a compressor must be assessed by a number of key
parameters, such as energy consumption, environmental impact and
manufacturing cost. Computational Fluid Dynamics (CFD) allows a reduction in
the development of compressors and also the analysis of phenomena that are
difficult to assess through experimental investigation. For instance, suction
and discharge systems are crucial components of reciprocating compressors,
affecting to a great extent their isentropic and volumetric efficiencies,
reliability and acoustic noise. Simulation models can be developed to analyze in details pressure pulsation in mufflers, flow
irreversibility and valve dynamics. CFD can also be applied in the thermal
management of compressors in order to assist the development of technologies
to manage thermal energy, its generation, dissipation and recovery. Numerical
models are particularly useful for thermal analysis of components and
simulation of extensive system interconnections. Mr Jack Sauls and Mr Scott Branch - Trane,
Ingersoll Rand, USA
Jack Sauls, Technology Leader Scott Branch, Compressor Design Engineer This brief presentation will focus
on examples of how CFD has been used to make specific decisions in the design
of refrigeration screw compressors for use in water chillers
for comfort cooling applications. Dr Maria Pascu - Howden Compressors
Ltd, Glasgow UK
Graduated from the Power Engineering Faculty,
University "Politehnica" Bucharest in
2005 with a major degree in Nuclear Power Plants -Obtained her Phd at the
Institute of Fluid Mechanics, LSTM Erlangen, Friedrich-Alexander University
Nuremberg, Germany in 2009 -Currently employed by Howden Compressors Ltd in the
position of R&D engineer -area of expertise: CFD in rotating machinery;
published one manuscript "Axial fan design. Modern layout and design
strategy for fan performance optimization" (2009) and over 15 journal
and conference papers. The shape of the suction port in a twin screw
compressor is often the subject of experimental investigations and the
general belief is that by opening the gas admission through a radial port at
the suction will have a positive effect on the compressor performance, as it
would improve the chamber filling process by reducing the throttling losses.
This hypothesis was tested against a standard WRV163145 compressor and two
suction scenarios were analyzed, both
experimentally and numerically: one with axial port at the compression
chamber entry (the original compressor), the second including the same axial
port, as well as a radial port machined-off from the inner casing wall (the
modified compressor). Mr. Sham Rane - City University
London, UK
BE(Mech), MTech(Mech), PhD Student at
Centre for Positive Displacement Compressor Technology Research Interests • CFD solver and application development • Customized Grid Generation for Positive
Displacement Machines like screw compressors. • Uni-directional and Bi-directional
code coupling for multi-physics simulations The biggest challenge in 3D Transient CFD analysis
of Positive Displacement Screw Machines has been the availability of dynamic
deforming grids on which the conservation equations need to be solved. A remarkable
advancement was achieved in 1999 with the development of SCORG at City
University London. This tool is based on techniques of Algebraic Grid
generation with Transfinite Interpolation and Boundary Adaptation. SCORG has
been successfully used for Twin screw parallel axis machines for a long time. As the industry sees development of new types of
screw machines like Variable Lead, Variable Profile rotors, there is a need
to develop grid generation methods suitable for such variations and also for
existing machines like Single Screw Compressors. This lecture will demonstrate how customized grid
generation principles and tools can be developed and help CFD development of
screw machines. Some examples of recent upgrades of SCORG to generate grids
for Variable geometry rotors will be presented. Prof. Manolis Gavaises - City
University London, UK
Prof Gavaises is the director of Energy &
Transport Research Centre at City University London. He is a member of the
editorial board of Atomisation & Sprays, Applied Mathematics and
International Journal of Engine Research. He is on the organisation committee
of the IMechE Conference for Fuel Injection Systems for IC Engine, the SIA
Conference on Diesel Powertrains and he is the Chairman of the 2013
ILASS-Europe Conference. CFD simulation of the flow in screw compressors is a
complex task: the changing geometry and the very small leakage passages pose
difficulties not only to the creating of numerical grids but also on the
implementation of methodologies able to resolve the detailed fluid dynamics
in such areas. In case of multi-phase flow formation, things become even more
complex as there is no experimental information on what type of flows may
exist and what models are appropriate for their simulation in such machines.
In light of that, this presentation provides a review of relevant multi-phase
flow models, their applicability range and their relevance to flow conditions
realised in screw compressors. Without having attempted yet to simulate such
cases, it is speculated which methodologies sound more appropriate for
resolving such cases and what experiments could be designed for their
experimental validation. Costs
The
fee for the course is £360 for conference delegates and £480 for those
attending course only. The fee
includes lecture materials on CD and in the paper form, refreshments, lunches
and the evaluation copy of DISCO software with the training lesson. Register
To express interest in attending the course and to
register for the course please see: Compressors Conference pages on our online store |
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prepared and maintained by: Prof
Ahmed Kovacevic
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