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: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=389853
• 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、外部加热或其他机械损坏的压力液化气体(PLG)容器中可能出现的安全壳丢失(LOC)失效机制的模型；ii)检查、测量、模拟和验证复杂的工业换热和流体流动损失预防情况；以及iii)继续开发和改进用于同时确定流体导热系数和热扩散率的瞬变线源技术。1)大型液化石油气容器喷射火灾暴露试验的研究结果表明，两相动态再增压和/或两相淬火换热的过程可能是已记录的一些更猛烈的沸腾液体膨胀蒸汽爆炸(BLEVE)事故的原因。在这次毕业典礼上，来自于一个局部的‘断前泄漏’(LBB)LOC。试验初步证实，裂纹引起的降压导致已经成核的过热液体产生快速气泡增长和水平膨胀，这可能会导致足以使裂纹变得“关键”并完全失效的再加压，和/或由此产生的两相排放，以“淬火”热蒸汽壁中的裂纹尖端，导致巨大的拉应力，与再加压和其他容器负载的拉应力相结合，导致容器灾难性的“解压”。2)对弗利克斯伯勒灾难的历史记录进行了更正分析。目前正在进行将这项工作扩大到包括液化天然气风险。这项工作应该对化工和加工工业以及监管机构有价值。在三)用于测量大范围温度和压力范围内流体的导热系数和扩散系数的瞬变线源热线仪器，在操作和精度方面得到了改进，确定了几个主要的测量方法，并且最近执行了一些被忽视的修正-分析-程序来实施这些方法。