Catastrophic failure of large storage facilities, containing cryogenic fluids
Author(s)
Su, Rochmadi
Type
Thesis
Abstract
The sudden release of cryogenic liquid resulting from Catastrophic Tank Failure (CTF) and its interaction with vertical bunds has been investigated theoretically. Once the tank wall has ruptured, the phenomenon of CTF itself is regarded as a collapse of a vertical, squat liquid column under its own weight. The resulting flow rushes to and collides with a vertical cylindrical bund, coaxial with the liquid column, and returns to the column axis as a strong hydraulic shock. If the bund is low, overflow occurs. The flow description is based on Shallow Water theory, and the governing equations are solved by the Method of Characteristics. Consistency of the results has been checked against the principle of mass and energy conservation. In preparation, the first part of the work is concerned with re-investigation of non-boiling liquid release, which has already been examined theoretically and experimentally by several authors. The calculated energy loss at the shock agrees within 1 % with the energy discrepancy, defined as the calculated total energy content at any time level less the total theoretical initial energy content. The calculated amount of overflowing liquid also agrees within 1 % with the mass discrepancy ( the calculated total mass less the total theoretical initial mass ). The maximum shock height at the bund is equal to that estimated previously (Kleyn, 1983), but such work under estimated the amount of overflowing liquid. The results of this study also roughly agree with the experimental results (Greenspan and Johansson, 1981; Sharifi, 1987). Cryogenic liquid release is described in the second part of the work. As cryogenic liquids boil vigorously on contact with the ground, the proposed model considers that the cryogenic liquid flow contains vapour, which forms a two-phase layer on the ground surface. The two-phase layer thick ness depends on: boiling rate, horizontal flow velocity, column height and diameter, physical properties of liquid and vapour, and the vapour motion in the flow. The flow region is divided into: non-boiling, density-change and vapour-release regions, with each region having its own governing equations. This work only gives general description of the two-phase, unconfined and confined flow. Further theoretical and experimental investigations are
needed. The theoretically predicted propagation velocity of the moving front is around 1.7-1.83. Comparison with results for non-boiling liquid flow has shown that for cryogenic liquid flow, the shock height at the bund and the amount of overflowing liquid are higher than for non-boiling liquid flow. It is concluded that the model for non-boiling flow cannot be used to describe appropriately cryogenic liquid flow.
needed. The theoretically predicted propagation velocity of the moving front is around 1.7-1.83. Comparison with results for non-boiling liquid flow has shown that for cryogenic liquid flow, the shock height at the bund and the amount of overflowing liquid are higher than for non-boiling liquid flow. It is concluded that the model for non-boiling flow cannot be used to describe appropriately cryogenic liquid flow.
Date Issued
1991
Date Awarded
1991
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Michels, Dr. H.J.
Sponsor
Inter University Center Engineering section at Gadjah Mada University
Publisher Department
Chemical Engineering and Chemical Technology
Publisher Institution
University of London - Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)