Fire & Explosion / CFD
CFD for Fires and Explosions
There is often a need to performed detailed Computational Fluid Dynamics CFD modelling to calculate consequence and exceedence as well as compare layout options, examine the benefit of incorporating additional fire/blast walls, determine Design Accidental Loading (DALs). We have carried out hundreds of such studies including:
• Consequence analysis for targeted events;
• Probabilistic Analysis for onshore and offshore facilities;
• Optimisation of equipment layouts/orientation;
• Maximisation of natural ventilation and blast venting;
• Impact of fire/blast wall layout and additional barriers;
• Benefit of additional fire/blast barriers;
• Optimisation of gaps between modules;
• Plated versus grated decks;
We have designed our own explosion modelling software which is easy to use and far more accurate than existing analytical relations which are the most widely used method ( see video ). Our experts also have unparalleled expertise in a number of other software including FLACS, EXSIM FLUENT and others.
Helideck Studies and Thermal Plume Analysis
Helideck studies are performed using CFD. Typically a study will include simulations of wind flow to assess if general air flow conditions above helideck is in line with requirements of the CAP 437 standard.
The result from the analysis is usually compared to the requirements of the relevant standard ( often CAP 437) and it identifies what percentage of time during a year when requirements are breached. These studies are best carried out using software that has advanced turbulence capabilities such as FLUENT, ACE or CFX.
For thermal plume analysis, simulations of exhaust releases and other potentially relevant release sources (fin fans, large HVAC outlets etc) are carried out using CFD. The objective of these simulations will be to assess whether exhaust releases will affect items in the plume's vicinity such as crane operator cabins and helidecks and cause unacceptable temperature gradients or dangerous operating conditions.
Fire and Gas Detection Studies
We use CFD to model fire and gas detection systems are an important risk reducing measure on facilities where there is potential for fire, explosion, or toxic releases.
The Fire & Gas detection system should enable mitigation of hazardous conditions such as fire or loss of containment by performing three basic functions:
• Detect the Hazard;
• Alert People;
• Initiate Action.
The use of CFD enables the optimisation of detector placement in order to enable the detection of all significant releases, while not unnecessarily hindering facility operation using the minimum number of detectors possible. CFD of fire and gas detection systems are some of the most cost effective studies any major hazard facility can carry out.
We also carry out general purpose Computational Fluid Dynamics (CFD) analysis support in a wide range of applications including
Flow assurance in gas and liquid pipelines
Modelling cavitation and turbulence
Liquid sloshing modelling
Heat exchangers modelling
Pipe and valve erosion
Natural and forced ventilation of buildings
Subsea Releases CFD
Subsea releases are a complex fluid modelling case in which gas and condensate among other components are released at high pressure at the seabed. The release including the gas which is composed of bubbles that tend to break up while being transported upwards under the influence of buoyancy and transported laterally by the currents which has varying speeds and differing directions at various depths below the surface.
The gas then is released from a typically wide area at the sea surface, mixing with the air and forming a flammable and/or toxic cloud.
Other outputs include the forces on the capping stack as it is lowered to the sea bed. These include drag and lift as well as torsion. The forces are important and calculated for operators as guidance for the lowering of the capping stack.