1,721,103 research outputs found
L'efflusso critico bifase da tubazioni: un incidente difficile da stimare
No full textThe two-phase release of substances stored or conveyed as pressure liquified gases is an accident of great interest in chemical and process industries and in transportation and its consequences can be also extremely serious owing to the quality (toxic or inflammable) of the accidentally released substance. As much interest is devoted to have reliable tools allowing to make a correct evaluation of the consequences, this study presents a new model which assumes different velocities for liquid and gas and evaluates the release by taking into consideration the flow pattern inside the pipe and the mixture quality too. A comparison between experimental data referring to critical discharges of freon 12, available in the open literature, and the predicted results obtained with the models most largely used in risk analysis, shows how big expected errors are
The use of HazOp and Fault Tree techniques for the assessment of non-accident induced release frequencies in the transport of hazardous substances
No full textTwo-Phase Choked Flow
No full textIn this paper a simple analytical relationship is presented in order to evaluate two-phase choked mass velocity emerging from a pipe owing to an accidental breakage, once critical pressure and quality are known. The proposed expression accounts for the dependence of the slip ratio on the flow patterns and can be applied to non horizontal pipes too
Accidental releases of two-phase multicomponent critical flow from horizontal pipes
No full textAn accident involving a two-phase release can result in serious consequences for people as well as the environment. Consequently, tools are needed to give accurate predictions of the discharge rate, physical state, composition of released material, and chocked pressure in order to improve process safety efficiency. This paper discusses possible approaches to the examination of two-phase critical releases and presents a slip equilibrium model which provides critical flow rate, critical pressure, and phase fraction of the two phases emerging from an accidentally broken pipe containing a liquefied gas mixture under pressure. Comparisons between experimental critical flow rates and model predict ions are favorable in both monocomponent and multicomponent mixtures
Il rischio da trasporto di sostanze pericolose: un'analisi dell'impatto territoriale con il TRAT2
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