Large Scale Molten Fuel Coolant Interaction Experiments: Explosion Initiation and Propagation

1347992 sonder这项拨款支持实验能力的发展，以控制影响参数和研究呼吸岩浆事件的行为。具体而言，pi将开发一个重要的，迄今尚未开发的，放大的设备，用于控制和观察触发的爆炸性渗透岩浆火山活动的行为：1)组装和开发一个可倾斜的熔炉，用于熔化天然火成岩；2)研制一种25-50升的绝缘坩埚，将熔体倒入坩埚中，通过坩埚的底部，水可以在整个熔体的各个孤立点注入，以形成一种渗透式预混料。其中，准稳定的水蒸气相将液态水从熔体中分离出来；3)开发一种触发系统（例如，一个气枪直接进入含有预混料的坩埚或锤击装置），以诱导分离的水蒸气相破裂，使热岩浆和液态水的直接相互作用引起快速冷却并导致爆炸性火山活动；4)用观察方法对坩埚进行仪器测量，以研究系统的机械和动力学行为（例如，安装在坩埚底部的高速力传感器来测量爆炸的垂直力，坩埚内的热电偶来测量熔体温度，高速摄像机来观察喷射）。该设备的开发将与德国维尔茨堡大学的科学家进行磋商，并聘请一名仪器系统工程和实验专业的博士生。最初的实验将改变预混合参数（注入水的几何形状和体积以及坩埚供应斜坡上的预压水）？动态预混料)，测试不同的触发机制和后续的喷射物研究（例如，粒度分析，空间分布，灰分矿物的结构和矿物学研究）。熔体成分将保持为实验常数。爆炸实验将在一个现存的室外设施（由纽约州立大学布法罗分校租用的地质灾害现场站）进行，该设施已被允许用于爆炸。该装置提出的规模代表了岩浆预混物体积增加两个数量级的潜力，迄今为止，这些岩浆预混物的体积已被实验控制以研究呼吸岩浆作用，并为研究呼吸岩浆行为以及有利于危险火山灰云和火山碎屑密度流形成的条件提供了一个有趣的中等规模参数空间。这种实验规模与自然系统的规模相距甚远，但应该为围绕呼吸岩浆作用性质的问题提供新的见解，包括：1)当熔体中的许多水域均匀分布和非均匀分布时，它们对爆炸强度的影响是什么？2)是否存在启动爆炸所需的最小触发能量，或者预混料是否可以自行有效爆炸？实验结果将输入模型，这些模型试图将实验室观察结果与自然系统行为进行比较

1347992SonderThis grant supports development of an experimental capability to control influencing parameters and study the behavior of phreatomagmatic events. Specifically, the PIs will develop a significantly and, as of yet unexplored, up-scaled device for controlling and observing the behavior of triggered explosive phreatomagmatic volcanism by: 1) assembling and developing a tiltable furnace for melting natural igneous rock; 2) developing a 25-50 L insulated crucible into which the melt would be poured and through the base of which water can be injected at various isolated points throughout the melt to create a phreatomagmatic ?premix? in which a quasi-stable water vapor phase separates the liquid water from the melt; 3) developing a trigger system (e.g., an air gun directed into the crucible containing the premix or a hammer device) to induce breakdown of separating water vapor phase such that direct interaction of hot magma and liquid water causes rapid cooling and leads to explosive volcanism; and 4) instrumenting the crucible with observation methodologies to study the mechanical and dynamical behavior of the system (e.g., high-speed force transducers mounted on the bottom of the crucible to measure the vertical forces of explosion, thermocouples within the crucible to measure melt temperatures, high speed cameras to observe ejecta). The development of the device will involve consultation with scientists at Wurzburg University in Germany and engage a Ph.D. student in instrument system engineering and experimentation. Initial experiments will varying the pre-mix parameters (injected water geometry and volumes and preloading of water down the crucible supply ramp ? dynamic premix), testing differing triggering mechanisms and subsequent study of ejecta (e.g., grain size analysis, spatial distribution, textural and mineralogical study of ash minerals). Melt composition will be maintained as a constant for experiments. The explosive experiments will be carried out at an extant outdoor facility (the GeoHazards Field Station leased by SUNY-Buffalo that is already permitted for explosives. The proposed scale of the device represents the potential for a two order of magnitude increase in the volume of magma premix that has hitherto been experimentally controlled to study phreatomagmatism and presents an interesting mid-scale parameter space to study of phreatomagmatic behavior and the conditions that favor hazardous ash clouds and pyroclastic density current formation. This scale of experiment is far from the scale of natural systems, but should offer new insights into questions surrounding the nature of phreatomagmatism including: 1) what is the influence of many water domains entrapped in the melt on explosion intensity when they are homogeneously and inhomogeneously distributed? and 2) is there a minimum trigger energy necessary to start the explosion, or can a premix effectively explode by itself? Experimental results will feed into models that attempt to scale laboratory observations to natural system behavior.***