Pipeline vibrations. Computer program for the prediction of fluid transients in flexible, unbranched three-dimensional piping systems.
Abstract:ESDU 93031 introduces a program, ESDUpac A9331, that directly accounts for the mutual coupling between internal pressure and flow conditions, and the stresses and structural motion of the pipework. The system must consist of straight pipes each of uniform cross-section and material properties running full of liquid and each aligned with one of a set of orthogonal axes. It is assumed that all bends remain right angles and do not flex. Externally-acting rigid supports can be modelled at any location in any or all the three translational and three rotational degrees of freedom. The system can have a reservoir or a centrifugal pump (running at constant speed or running down after trip) at the upstream end, and a reservoir or a valve (opening, closing or fixed) at the downstream end. Data on the pump characteristics and rotor inertia are required (although default data are included) and allowance may be made for backflow. The valve may be closed instantaneously, with a linear area change with time, or an area/time closure curve may be input. Output includes steady-state values, together with maximum and minimum values and their location, of pressure, velocity, pipe displacement, axial and shear forces in the walls, and torsional and bending moments in the walls; the time variation of user-chosen variables at selected locations over the run time can also be provided. Criteria by which it can be established whether structural coupling is important are defined and their use discussed.
|Data Item ESDU 93031|
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