Piping Slug Flow Simulation





Piping, CFD, Fluid dynamics, Cradle


UK, Cheshire


Multiphase flow occurs when different fluid phases are mixed and flow along the pipe. Because of the phase velocities, densities and the ratio of liquid to gas, different flow regimes might exist , i.e. stratified, slug or annular flow.

Perhaps the most damaging is the presence of fast moving liquid slug flow as this may cause structural problems with the existing pipework. For example, small liquid slugs with higher frequency may cause vibration leading to fatigue over time. Large liquid slugs that occur less often may lead to a pipeline overload with catastrophic results.

However, these slugging problems may be anticipated and mitigated by detailed CFD analysis using software such as Cradle. Cradle is a proven, state of art, world-leading CFD simulation software.

The challenge

This kind of phenomenon involves the presence of fast-moving liquid slug flow which may cause structural problems during impact with the pipework. A CFD simulation involving non-homogeneous multi-phase slug flows through a piping system such as those performed by MSC Cradle, or a simpler 1D fluid assessment such as in FLOWNEX, can be used to approximate the exact forces generated in a piping system during specific transient regimes.


The DOCAN solution

A time-history of forces acting on each bend can then be exported to use as input to appropriate software, in order to allow transient stress and deflection studies to be carried out.


The outcome

This method of calculating forces due to slug flow can highlight areas of the pipework and support structures which may have been calculated as overstressed using traditional code-based approaches, but which actually may not be overstressed.

DOCAN are familiar with a variety of software and programs such as Fluent or OpenFOAM and can be used at the client’s request.


Project summary

TaskApplicationDOCAN design expertiseSolidworksCFDCradle
CAD geometryBuild 3D model
CFD model bulidingModified Parts and Meshing
Flow rates & boundary conditions
Piping AnalysisTransient Scenario
Multiphase flow
Vibration and fatigue

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