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Explosions and fluid dynamics
DTU Building 421, room 002
Wednesday 5. April 2017,  12.00 - 16.20


DANSIS invites you to a seminar that will be on the fluid mechanics of explosions in different applications. Major explosions accidents are presented. Presentations will describe modelling and experimental investigation of explosions. They will also address risk management of major accident hazards. The program will be updated soon.

 

Program 
11.30 Registration
12.00 Welcome
Kenny Krogh Nielsen, Lloyd's Register
12.10 Explosions and detonations - concepts and basic principles 
Peter Glarborg, DTU Chemical Engineering
Premixed combustion of a flammable fuel-air mixture may result in a deflagration (flame), a detonation, or an explosion, depending on the physical conditions. For most practical applications, detonations and explosions are undesired and it is important to understand what may lead to these phenomena. In this presentation, the characteristics of these phenomena are outlined. Selected examples from industry are discussed.
12.40 Break with sandwiches
13.10 Explosion mechanisms and the Development of risk assessment approaches - experiments, accidents, 3D-modelling of explosions and risk
Olav R. Hansen, Lloyd's Register  slides
The development of explosion phenomena knowledge over the past few decades is described through important large scale experiments, major accidents and the development focus of 3D explosion modelling in risk assessment studies. Different steps of a state-of-the-art explosion risk assessment are shown, the importance of proper modelling is discussed. The more exact and detailed the physics is modelled, the better is the potential for optimizing layout, design and safety measures.
 
13.55 Coherent explosion modeling in KFX™-EXSIM based on the Eddy Dissipation Concept
Kjell Erik Rian, ComputIT    slides
Explosions and fires represent the most serious accidents in the oil and gas industry. To prevent or mitigate explosion and fire related accidents, the industry needs advanced predictive technologies to pre-design the safety measures. Here, the background and development of the industrial CFD tool KFX™-EXSIM for 3D gas explosion analyses in complex geometries is presented. The KFX™ simulation technology uses the same combustion physics modeling concept to model both gas explosions and fires. Furthermore, it is coupled to advanced models for non-linear dynamic structural response analysis and integrated with risk models for consistent, time-dependent risk management and barrier control (named KFX™-RBM). Examples from large-scale validation and industry application are included.
14.40 Coffee break 
15.10 Recent Developments in Safety Analysis: Modeling of Gas explosions in Safety Gaps and FLACS Risk - Next generation of 3D Risk analysis for Dispersion, Fire and Explosions
Franz Zdravistch, Gexcon     slides
FLACS 3D-CFD is already a well established and thoroughly validated technology for predicting the consequences of gas dispersion, fire and explosion events. The accuracy provided by 3D CFD predictions is required whenever structures, equipment, piping or any other geometry is present. However, additional improvements to the existing turbulence and combustion models are currently being developed to validate the flame propagation behaviour in FLACS when applied to safety gaps.  Preliminary results of this research project will be presented. In addition, Gexcon A.S. has recently released the first version of FLACS-Risk, an integrated tool that streamlines the setup, processing and postprocessing of FLACS simulations in order to perform probabilistic risk analysis more efficiently. Traditionally, probabilistic analysis have been done using alternative in-house tools. In this presentation, the FLACS-Risk Project Based approach will be introduced, including details of how to setup, run and postprocess the simulations, as well as 1D and 2D/3D exceedance calculations. Examples for specific cases will be shown and discussed.
15.55 Enhanced gas explosion risk management through improved ignition control of gas turbine air intakes – with a particular focus on fluid mechanics
Ingar Fossan, ComputIT, and Kenny Krogh Nielsen, Lloyd's Register     slides
Currently, the industry does not have a fundamental understanding of the behavior of gas turbines when intake air includes flammable gas. Two incidents has taken place in the North Sea after year 2000 where it is believed that the gas turbine air intake was the source of ignition, one of which occurred at the Danish Continental Shelf. As of today this problem appears to be the most important single source of ignition on many offshore installations. An ongoing Joint Industry Project investigates the ignition mechanisms and exploring ways to mitigate the risk. In this presentation the background problem is presented based on an actual accident investigation. The fluid mechanics aspects of gas dispersion and explosion modelling are represented. The ignition and propagation mechanisms within the gas turbine are governed by fluid mechanics. These are addressed together with potential mitigating measures.
16.25 Closing, future DANSIS activities 
Knud Erik Meyer, DANSIS chairman
16:30 End
16:40 DANSIS general assembly

Members of DANSIS can participate in the seminar free of charge. Non-members are also invited to participate at a fee of 400 DKK.

Register for the meeting
DANSIS - The Danish Society for Industrial Fluid Dynamics     Email: dansis@dansis.dk