Loss prevention, heat transfer and thermal properties

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The current research program has three long-term objectives: i) to develop and experimentally verify models of possible loss of containment (LOC) failure mechanisms in partially filled, externally heated or otherwise mechanically damaged, pressure liquefied gas (PLG) vessels, ii) examine, measure, model and verify complex industrial heat exchange and fluid flow loss prevention situations, and iii) continue to develop and refine the transient line source technique for the simultaneous determination of the thermal conductivity and thermal diffusivity of fluids. In i) results from examinations of large-scale LPG vessel jet fire exposure trials indicate that a process of two-phase dynamic re-pressurization and/or two-phase quenching heat transfer may be responsible for some of the more violent Boiling Liquid Expanding Vapour Explosion (BLEVE) accidents that have been recorded. In this commencement comes from a partial 'leak before break' (LBB) LOC. It has been tentatively verified from trials that the  depressurization resulting from the crack causes an already nucleated and now superheated liquid to yield rapid bubble growth and level swell which may cause a re-pressurization sufficient to cause the crack to become 'critical' and fail completely, and/or the resulting two-phase discharge to 'quench' the crack tip in the hot vapour wall, resulting in large tensile stresses that combined with those of the re-pressurization and the other vessel loads result in a catastrophic 'unzipping' of the vessel. For ii) analyses have been made to correct the historical record for the Flixborough Disaster. Extension of the work to include LNG risks is now being undertaken. This work should be of value to the Chemical and Process Industries as well as regulators. In iii) The transient line-source hot-wire instrument, for measurements of the thermal conductivity and diffusivity of fluids over a wide range of temperature and pressure, has been  improved in operation and precision with the identification of several major, and recently, overlooked corrections-analysis - procedures to implement these have been implemented.