Loss prevention, heat transfer and thermal properties

防损失、传热和热性能

• 批准号: 8859-2007
• 负责人: Venart, James
• 金额: $ 1.31万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=364685
• 关键词: Loss; prevention; heat; transfer; thermal

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.

目前的研究计划有三个长期目标：i）开发和实验验证部分填充的、外部加热的或以其他方式机械损坏的压力液化气体（PLG）容器中的可能的安全壳损失（RISK）故障机制的模型，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，以及iii）继续发展和完善瞬态线源技术，以同时测定流体的导热率和热扩散率。在i）中，大型液化石油气容器喷射火灾暴露试验的检查结果表明，两相动态再加压和/或两相淬火热传递过程可能是已记录的一些更剧烈的沸腾液体膨胀蒸气爆炸（BLEVE）事故的原因。此次启动源于部分“破裂前泄漏”（LBB）LOC。从试验中已经初步证实，由裂纹引起的减压导致已经成核并且现在过热的液体产生快速气泡生长和水平膨胀，这可能导致足以导致裂纹变得“临界”并完全失效的再加压，和/或导致两相排放以“淬火”热蒸汽壁中的裂纹尖端，导致大的拉伸应力，该拉伸应力与再加压和其它容器载荷的拉伸应力相结合，导致容器的灾难性的“拉开”。对于ii）已经进行了分析，以纠正Flixborough灾难的历史记录。目前正在扩大工作范围，以包括液化天然气风险。这项工作应该是有价值的化学和加工工业以及监管机构。在iii）瞬态线源热线仪器，用于测量流体的热导率和扩散率在很宽的温度和压力范围内，已被改进的操作和精度与几个主要的识别，最近，被忽视的校正分析程序，以实现这些已经实施。