Loss prevention, heat transfer and thermal properties

目前的研究项目有三个长期目标：i)开发和实验验证部分填充、外部加热或其他机械损坏的压力液化气（PLG）容器中可能的容器泄漏（LOC）失效机制的模型；ii)检查、测量、建模和验证复杂的工业热交换和流体流动损失预防情况；iii)继续发展和完善瞬态线源技术，以同时测定流体的热导率和热扩散率。i)大型液化石油气船喷射火灾暴露试验的结果表明，两相动态再加压和/或两相淬火传热过程可能是造成一些已记录的更猛烈的沸腾液体膨胀蒸汽爆炸（BLEVE）事故的原因。在这种情况下，开始来自部分“先漏后破”（LBB） LOC。试验初步证实，裂纹产生的降压导致已经成核的过热液体产生快速的气泡增长和水平膨胀，这可能导致足够的再增压，导致裂纹变得“临界”并完全失效，和/或由此产生的两相放电使热汽壁上的裂纹尖端“淬火”。由此产生的巨大拉伸应力，再加上再加压和其他容器负载的压力，导致容器灾难性的“解压缩”。对于ii)已经进行了分析，以纠正Flixborough灾难的历史记录。目前正在进行扩展工作，以包括液化天然气风险。这项工作应该是有价值的化学和过程工业以及监管机构。iii)瞬态线源热线仪器，用于测量流体在广泛温度和压力范围内的热导率和扩散率，在操作和精度上得到了改进，确定了几个主要的，最近被忽视的校正-分析-程序来实施这些已经实施。

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.