Prediction of Blowdown Forces and Impingement Pressures From a Partial Pipe Rupture for Hazard Analyses
Notice bibliographique
Résumé
In the design of pipelines, various risk evaluations are undertaken to assess the threat to adjacent pipeline, structures and the surrounding population. This paper addresses how to assess the magnitude of a partial rupture in a high vapor pressure [HVP, Y-grade (combined ethane, propane, butane from fracking) liquid] pipeline with very high Charpy energy. The methodology is applicable to pipelines containing other fluids as well, but substantial development was needed to assess the example case presented. In this assessment it was found that a very quick arrest could occur due to the specific design variables, material toughness, and saturation pressure of the product, but the methodology to assess the length and opening area of such a partial rupture had to be developed. Based on past partial rupture pipe burst tests, the length of crack propagation first proposed by Maxey was extended to much tougher pipe cases that had more limited axial crack extension. The Maxey work had actual toughness to minimum arrest toughness values of up to ∼2, whereas the ratio for this sample case was 11. Data from a number of recent and past pipe burst tests with limited ruptures were used to further extend the Maxey correlation to cases of much shorter crack extensions during a rupture. Rupture length was determined as a function of design variables, material toughness and saturation pressure, enabling extension of this approach to a broad range of applications to either natural gas or high vapor pressure (HVP)/Y-grade liquid pipelines. Once the rupture length is known, then the crack-opening area of the resulting rupture is needed for blowdown calculations and hazard assessments. Some data were available from nuclear piping tests in the UK by CEGB, but a significant amount of additional data were added for the determination of the opening area in the shorter rupture length region of interest. Additionally, a small survey of service failures was conducted to determine the size of the crater from such ruptures. Once the opening area was known, then the PipeTech© software was used to determine the static pressure at the rupture mouth, and the mass flow rate. Additional analyses were used to determine the effect of the mass flow rate on creating a dynamic pressure from the impingement of the exhausting fluid on an adjacent parallel pipeline. For the case of an adjacent pipeline, this peak dynamic force was used in a FE analysis including the loss of soil support on the adjacent pipe from the crater created. It was determined that for cases where rupture length is limited by toughness, the loads on adjacent piping can be quite small, even with a number of conservative assumptions applied, suggesting that for the conditions explored, close spacing between adjacent pipelines can be tolerated without having to include the rupture of the smaller pipe in the hazard zone region. This analysis did not involve a thermal or debris analyses, although the opening areas calculated could be used for more precise evaluations of those concerns.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».