Sealing matters have many different aspects. Thanks to its various skills and advanced equipment, OCAS is in a good position to look at sealing-related problems from all angles.
Over the past years, OCAS has been actively involved in various projects dealing with the sealing of metallic components. This has resulted in the development of experimental test set-ups with the support of our engineering team. The results of these tests have been translated into numerical models.
Assess and predict leakage
Prediction and evaluation of leakage and leak tightness is an important issue in a multitude of high-pressure applications, such as valves, flanges and threaded pipe connections that are used under extreme service conditions.
To assess the leak tightness of a seal several empirically derived correlations with macroscopic properties (such as the maximum contact pressure and the contact width) have been reported in literature. These correlations have given rise to broad-stroke requirements laid out in international standards for liquid and gas tightness.
Such correlations are practical in every-day use, but they ignore the influence of the surface topology on the leakage behaviour of a seal. Moreover, the seal surface conditions can change due to the tightening method and operational conditions.
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Experiments and numerical simulations
Therefore, the OCAS team carried out a large number of experiments using an in-house developed set-up to fine-tune and validate numerical models.
In these experiments, the leak pressure in function of the contact pressure and internal pressure of seals has been measured for different surface topologies.
The first steps were taken to extend the existing model for calculating leak rate where the contact pressure is not uniform over the sealing width. To this end, a cellular automaton was programmed to model percolation with non-uniform contact probability.
“When pressure is high, accurate knowledge on sealing is required to guarantee operational safety and minimize fugitive emissions.”
Related scientific papers
Jeroen VAN WITTENBERGHE and John VANDE VOORDE, “Prediction of the leakage threshold for Hertzian contact seals: an experimental approach”, Proceedings of the ASME 2018 Pressure vessels and Piping Conference PVP 2018, July 15-20, 2018, Prague, Czech Republic, PVP2018-84622
John VANDE VOORDE and Jeroen VAN WITTENBERGHE, “Prediction of the leakage threshold for Hertzian contact seals: a cellular automata model”, Proceedings of the ASME 2018 Pressure vessels and Piping Conference PVP 2018, July 15-20, 2018, Prague, Czech Republic, PVP2018-84404
