Internal Fluid |
 
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Internal Fluid |
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Flexcom provides a comprehensive internal fluid modelling capability. Stationary internal fluids, uniform steady state internal fluid flow and multi-phase slug flow may all be modelled. If slugs are present in an analysis, they are displayed visually in the structural animation.
A stationary internal fluid in Flexcom is characterised by its mass density, pressure above hydrostatic and the height above zero datum to which it extends. The height input is used to determine whether elements are fully filled with fluid, partially filled or empty.
A fluid velocity may be optionally specified, indicating that steady state internal fluid flow is being modelled. Steady state internal fluid flow induces both a centrifugal force (related to pipe curvature) and a Coriolis force (related to pipe rotation). An additional dynamic pressure term which affects pipe wall tension is also modelled. Options are provided to suppress any of these terms in a particular analysis, allowing the relative significance of each term to be assessed.
Note that where a moving internal fluid is being modelled, the direction of flow is assumed to be consistent with the definition of the element set in which the fluid is present – i.e. the fluid flows from the start element of the set towards the end element. If you wish to reverse the direction of fluid flow, you should reorder the relevant element set definition, or specify a negative value for fluid velocity.
Further information on this topic is contained in the following sections:
•Gravitational and Inertial Forces
•*INTERNAL FLUID is used to define the properties of an internal fluid.
•*SLUGS is used to specify parameters relating to slug flow.
•*PRINT is used to request additional printed output to the main output file. Specifically, the OUTPUT=SLUG FLOW option is used to request additional data pertaining to fluid/slug flow.
If you would like to see an example of how these keywords are used in practice, refer to G03 - Rigid Spool.