This paper summarises the results from a blind-prediction study for models developed for estimating the consequences of vented hydrogen deflagrations. The work is part of the project Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations (HySEA). The scenarios selected for the blind-prediction entailed vented explosions with homogeneous hydrogen-air mixtures in a 20-foot ISO container. The test program included two configurations and six experiments, i.e. three repeated tests for each scenario. The comparison between experimental results and model predictions reveals reasonable agreement for some of the models, and significant discrepancies for others. It is foreseen that the first blind-prediction study in the HySEA project will motivate developers to improve their models, and to update guidelines for users of the models.
Les évents d'explosion sont couramment utilisés dans les industries de procédés en tant que solution de prévention pour protéger les équipements ou les bâtiments contre la surpression interne pouvant être générée par une explosion. Cependant, ces explosions ventilées sont très complexes et impliquent le couplage de nombreux phénomènes physiques. L'objectif principal de ce travail est d'évaluer les capacités prédictives de 4 codes de dynamique des fluides (CFD) utilisés par les 5 organisations via une comparaison avec les données expérimentales de Daubech et al., 2013. Sur cette base, des bonnes pratiques et des recommandations pour la modélisation CFD des explosions ventilées sont proposées.
Accurate prediction of condensation plays an important role in the development of high efficiency turbo-machines working on condensable fluid. Therefore it demands modeling of poly-disperse characteristic of number distribution function while modeling condensation. Two such kind of models are considered in this work and they are namely, quadrature method of moments (QMOM) and multi-fluid method (MFM) models. The vital difference between these two models lies in the method of discretisation of the droplet size distribution. Further, their numerical aspects like ease of implementation in general purpose computational fluid dynamics solvers, accuracy and associated computational cost are discussed. In order to obtain accurate thermodynamic properties, the real gas formulations defined in IAPWS-IF97 are used. These algorithms are applied to the compressible Navier-Stokes solver of Fluidyn MP and tests are carried on Laval nozzle and compared with the experimental measurements.
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