CFD for consequence prediction by gyvwpsjkko



FLACS User Group                                                                                                                    
                                                                                                                                                                                       Contact address:
                                                                                                                                                                                       GexCon, Box 6015, NO-5892 Bergen, Norway
                                                                                                                                                                                       Tel.: +47 5557 4330, Fax: +47 5557 4331
One of the obligations for GexCon stated in
FLACS contracts is to organise an active FLACS
user group (FLUG). There are regular FLUG mee-
tings twice a year, usually combined with techni-
cal workshops.

The FLUG spring meetings are held in Bergen in May.
In addition to this, meetings have been organised in
connection to AIChE Spring meetings in April. In Oc-
tober/November the autumn meeting is normally held             FLACS Hands-on workshop for 60 students at Hydrogen Safety Summer School
at the premises of one of the users, this is often combi-
ned with an open industry seminar. At the meetings in          FLACS Training and workshops
Zurich in 2006, more than 50 participants attended the
industry workshop, and 25 FLACS users contributed              6-10 times a year a FLACS-I training course is held either at
to interesting discussions during the FLUG meeting.            GexCon offices or at the premises of a customer. During the
                                                               FLUG spring meetings an advanced training course will be
                                                               held. In addition to this occasional workshops are sometimes

                                                               One essential requirement for
                                                               good quality predictions among
                                                                                                      a 3 days’ FLACS-I introductory
                                                                                                      course is:
                                                                                                                                               CFD for consequence prediction                                                                      Contents
                                                               users is that they receive pro-                                                                                                                                              2      FLACS R&D History
                                                               per training. For about 10 years       • Introduction to explosions,            FLACS has been the leading tool for explosion consequence prediction on
                                                                                                                                               offshore oil and gas installations for more than a decade. Every year FLACS                         Read about the extensive work
                                                               there has been a 3 days begin-           R&D and mitigation
                                                                                                                                               is used in safety studies and risk assessments on more than a hundred off-                          behind the development and vali-
                                                               ners course. A training for ex-        • FLACS interfaces, define sce-
                                                                                                                                               shore facilities in most parts of the world.                                                        dation of the CFD-tool FLACS
                                                               perienced users is carried out           nario, geometry, grid embed-
                                                               during spring meetings 2007.             ding, and extract results                                                                                                                  Who is using FLACS?
                                                               Prior to this training course          • Hands-on exercises (disper-            More than 25 years of dedicated development in close cooperation with leading                       In-house used in more than 40
                                                               users will perform homework              sion and explosion)                    oil and gas companies is behind FLACS. With increased precision level of risk as-                   companies and organizations
FLACS User Group is watching a propane explosion demon-        exercises that will be discussed       • Validation and quality assu-           sessments, the modeling of ventilation and dispersion have become very important                    from 15 countries and various in-
stration test at GexCon test site at spring meeting May 2006   during training. The content of          rance (QA)                             elements of explosion safety studies and, therefore, dispersion functionality is well               dustries. 100s of companies have
                                                                                                                                               integrated in FLACS. During the last decade the use of FLACS on landbased                           used FLACS through consultants.
                                                                                                                                               petrochemical plants and for other industries has increased strongly, including              3      Different FLACS tools
GexCon -the explosion expert                                                                                                                   several incident/accident investigations.                                                           Dedicated tools are developed to
                                                                                                                                                                                                                                                   address the needs for different in-
The explosion activities at GexCon (CMR/CMI)                                                                                                   Continuous efforts are invested to improve FLACS and extend the applicability.                      dustries and application areas.
started 30 years ago. Today GexCon has 3 depart-                                                                                               Recently there have been significant efforts to extend and improve the dispersion
                                                                                                                                               capabilities of FLACS. GexCon has worked hard to establish FLACS as the lead-                       User interfaces and applicability
ments all working with different aspects of explo-                                                                                                                                                                                                 Learn about the tailor-made user
                                                                                                                                               ing hydrogen safety CFD-tool. To address explosion safety in the process industry
sion safety.                                                                                                                                   handling powder, a dedicated dust explosion tool, DESC, has been developed.                         interfaces of FLACS
GexCon Software department:                                                                                                                                                                                                                 4      FLACS training courses
• Sale and lease of FLACS and DESC software tools                                                                                              For a consequence tool like FLACS to be accepted by industry, a proper validation                   Proper training is needed to ensure
• Specialist consulting, advanced use of FLACS                                                                                                 against experiments is essential. User guidelines have been developed based on                      quality of predictions and limit user
• FLACS development, explosion contract research                                                                                               the validation to minimize user dependency. It is also important that the tool is ef-               dependency
                                                                                                                                               ficient in use, with short preparation and calculation times. Other advantages with                  FLACS Users Group FLUG
GexCon Consulting department:                                                                                                                  FLACS is a competent and active support team, frequent training courses, and an                     Forum for exhange of knowledge
• FLACS explosion assessments and safety studies                                                                                               active user group. The license structure is flexible, allowing short and long term                   and experiences
• Accident/incident investigations                                                                                                             leases in addition to perpetual licenses.
                                                                                                                                                                                                                                                   About GexCon
• Offshore/onshore petrochemical plants and other                Examples of scenarios for which explosion safety studies have been perfor-
  situations where flammable gases are handled                    med are refineries, transformers in power plants and gas powered ferries.

GexCon Process Safety department:
• Test laboratory and large-scale experimental site                                                                                                                                                                                                Could FLACS be
• ATEX risk assessments and testing for certification                                                                                           Reasons to use FLACS                                                                                useful to you?
• Dust explosion / process safety consulting                                                                                                   •   Efficient geometry handling through CAD-import and distributed porosity concept                  Contact us for information about
                                                                                                                                               •   User guidelines based on extensive validation against experiments                               the next FLACS training course!
GexCon Software and Consulting are providing servi-                                                                                            •   Developed in close cooperation with oil and gas industry                                        Register for a 3-days begin-
ces to customers all over the world. For Process Sa-                                                                                           •   Wide applicability: ventilation, dispersion, explosion, dust, hydrocarbon and hydrogen          ner course and obtain a free
fety the main markets are the Scandinavian countries                                                                                                                                                                                               evaluation period afterwards.
and Europe. GexCon is an SME owned by the rese-
arch institute CMR, with the University of Bergen as
majority owner.                                                   Vented flame from dust explosion testing at GexCon test site
2                                                                                                                                                                                                                                                                     3

FLACS R&D history                                                                                                                             Different FLACS tools and pricing
The FLACS development started in 1980. With mas-                                                                                              The FLACS applicability is gradually enhanced and the validity improved through continuous development. In
sive support from 7 major oil and gas companies the                                                                                           order to address the market better, dedicated tools have been developed or defined which are either reduced
first version, FLACS-86, was developed in parallel                                                                                             versions of FLACS, or tools with specialized functionality.
with an extensive experimental test activity. The de-
velopment initiative remained with the oil industry                                                                                           The full version of FLACS includes        FLACS pricing depends on tool (Full     • International Consulting (unlimited
until 2000. In recent years a reduced R&D volume                                                                                              the functionality of most tools (ex-      FLACS or Reduced), number of li-          use)
from industry has been compensated with increa-                                                                                               cept Aerosol & DESC). The following       censes, purchase or lease (short        • Domestic consulting (geographical
sed funding from the EU, Norwegian Research Co-                                                                                               FLACS versions with reduced or dif-       term or long term) options and li-        limitation)
uncil (NFR), and gradually an increasing volume of                                                                                            ferent functionality exist or are under   cense level. Details about this can     • Company Internal Use (no exter-
                                                                                                                                              development:                              be found in our global price list (e-     nal consulting)
maintenance payments from users.
                                                              Extensive test programmes were carried out in parallel with model development                                             mail for pricing        • Non-commercial R&D and Acade-
 Through 1980s and 1990s the main            formed elsewhere to validate FLACS.         involved in various networks and R&D                 • FLACS-DISPERSION - ventilation          information). The different license       mic licenses may be issued when
focus in the FLACS development               The dispersion models were further          activities within hydrogen safety, and                 and dispersion                          categories are:                           of strategic value to GexCon
was the needs of the oil and gas             developed and validated for atmosp-         FLACS is becoming a leading tool for                 • FLACS-HYDROGEN - hydrogen
industries. GexCon (CMR/CMI) per-            heric dispersion, including the spread      hydrogen safety consequence mode-                      safety
formed 100s of experiments to build          of non-flammable substances. The             ling.                                                • FLACS-GASEX - gas explosions
up an understanding of the physics           development of liquid pool models                                                                • FLACS-ENERGY - secondary
                                                                                         In cooperation with several European
of gas explosions. With improved             predicting spread and evaporation of                                                               transformer explosions
                                                                                         organisations and with support from
precision of the prediction tools, the       liquified gases (e.g. LNG) is one of                                                              • DESC - dust explosion
                                                                                         EU, the DESC dust explosion tool was
development focus shifted towards            the more recent improvements. The                                                                • FLACS-TNT - Simplified repre-
                                                                                         developed based on FLACS techno-
topics like modeling of water mitiga-        distributed porosity concept, which is                                                             sentation of high explosives (Add-
                                                                                         logy. DESC is a dedicated simulation
tion, gas dispersion and explosion           very important for the explosion mo-                                                               on to full FLACS)
                                                                                         tool for dust explosion safety and can
of non-homogeneous gas clouds,               deling with FLACS, also represents                                                               • FLACS-AEROSOL - aerosol parti-
                                                                                         be used to evaluate the safety of pro-
and tests to validate more advanced          a significant advantage compared to                                                                 cles (in-house R&D version under
                                                                                         cesses where standards and guideli-
CFD-based risk assessment appro-             competing dispersion models.                                                                       development)
                                                                                         nes have limitations.
aches.                                                                                                                                        • FLACS-FIRE - modeling of fires
                                             With the increased focus on envi-           Ongoing modeling efforts include fire                   (under development)
At this stage the development focus          ronment and hydrogen as an energy           modeling, improved CAD-import filters
gradually changed to address new             carrier, hydrogen safety has become         and the development of the next gene-
application areas, and also to a gre-        an important topic to address. With         ration GUI available on Windows and
ater extent using experiments per-           support from EU and NFR GexCon is           Linux.

Who is using FLACS, for what?                                                                                                                 FLACS user interfaces and efficiency
In the early years around 1990 major oil and gas companies                                                                                    For a consequence prediction tool not only the applicability and vali-
were the only in-house users of FLACS. In 1996 FLACS be-                                                                                      dity are important, but also the efficiency when preparing and perfor-
came commercially available. With the spread geographically                                                                                   ming calculations. FLACS is efficient compared to similar tools. This
and in application area seen today a typical FLACS user no                                                                                    applies even more for complex geometries with 100.000 geometry
longer exists.                                                                                                                                primitives or more.

The first commercial users were          that, other industries may have other                                                                Whether the geometry studied has          FEM or structural strenght assess-
consulting companies offering simu-      focus areas. Some examples are:                                                                      100.000 or 20 geometry objects does       ments. Preparation or simulation
lations to clients world-wide, mainly                                                                                                         not influence the calculation times        times for an experienced user would
within the oil industry. Gradually       •   Quantitative risk assessments                                                                    signicantly with FLACS. The geome-        depend on complexity of case:
new industries started to see the        •   Accident/incident investigations                                                                 try import programme geo2flacs, can
benefits from using FLACS inclu-          •   Identify/evaluate worst-case                                                                     import 100.000 or more objects fairly     • CAD geo import 1h to 1 week
ding loss prevention departments of      •   Safety evaluation of modifcations                                                                efficiently from CAD. For an experi-       • Geometry by hand 1h to 3 months
chemical companies, nuclear safety       •   Explosion venting of coupled and                                                                 enced user, dispersion or explosion       • Prepare first scenario 10 min to 8h
companies, manufacturers of safety           non-standard vessels                                                                             scenarios can thereafter be prepared      • Prepare new scenario 1 min to 1h
equipment, shipyards, construction/      •   Room/module layout optimisation                                                                  quickly using the dedicated CASD          • Explosion sim 10 min to 6h / CPU
engineering, research organisations,     •   Predicting the effect of mitigation                                                              preprocessor. Calculations (1 CPU)        • Dispersion sim 1h to 48h / CPU
as well as governmental institutions     •   Blast waves and control rooms                                                                    are generally fast. If you have many      • Result generation 5 min to 2h
and universities.                        •   Drag loads on piping                                                                             jobs to run these can be distributed
                                         •   Exhaust pipe explosions                                                                          to different CPUs, e.g. with 10 CPUs      The same geometry model can be
The application of FLACS is quite        •   Toxic gas dispersion                                                                             in a network. Result presentation is      used for dispersion and explosion.
varied among the different users.        •   Helideck studies                                                                                 done with our FLOWVIS postpro-            Consultants may perform 100 or
On petrochemical installations and       •   LNG dispersion studies                                                                           cessor, which can produce plots and       more simulations in connection to       FLACS has a dedicated pre- and post-proces-
plants the main concern may be sig-      •   Gas detector optimisation                                                                        animations directly. Possibilities also   e.g a QRA-project.                      sor. A current porting process to QT/Windows
nificant hydrocarbon releases, and        •   Planning and QA of experiments                                                                   exist for export to ASCII for input to                                            will further modernize these.
the possible consequences from           •   Assist certification processes                      Geographic distribution of FLACS users

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