Session: DA-02-01: Design & Analysis of Piping and Components I

Paper Number: 61797

Start Time: Tuesday, July 13, 2021, 09:00 AM

61797 - Assessment of Dynamic High Momentum Slug Loads on Piping Following STHE Tube Rupture 

Transient fluid loads in process piping have gained renewed focus recently with the design and construction of many new Liquefied Natural Gas (LNG) Plants.  Shell and tube heat exchangers (STHEs) are sometimes used in inlet areas of LNG Plants to heat high pressure incoming feed gas.  The tube side contains high-pressure feed gas while the shell side contains a relatively low-pressure heating medium liquid. Tube rupture can lead to transient fluid loads in the form of an initial shockwave (waterhammer) event followed by high momentum slug flow in the liquid piping.  While the waterhammer event has been reasonably well studied, less attention has been paid to the high momentum slug flow that can occur afterwards when liquid slugs are accelerated in the piping by the gas.  The high velocities combined with the liquid densities of the slugs can result in severe loads on piping and piping supports.

This paper will examine some of the practical considerations for assessing the dynamic loads resulting from this high momentum slug flow. A method to obtain the force vector for any three-dimensional change in piping direction will be presented.  The use of dynamic load factors (DLFs) for loads where a detailed time history profile is available will be discussed.   The possibility of taking credit for simultaneously acting forces will be investigated. The applicability of the of the B31.3 allowable stress for occasional loads will be examined and compared against more advanced finite element models using shell elements.

Presenting Author: Robert Weyer Amesk

Authors: