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

1347992 Sonder这笔赠款支持开发实验能力，以控制影响参数并研究脉络膜岩浆事件的行为。具体地说，PI将开发一种重大的、迄今尚未探索的、规模较大的设备，用于控制和观察触发的火山喷发的行为，方法是：1)组装和开发一种用于熔化天然火成岩的可倾斜熔炉；2)开发一种25-50 L绝缘的熔炉，熔体将被倾倒在其中，并通过其底部在熔体中的不同隔离点注入水，以产生熔体？熔浆预混料？其中准稳定的水蒸气相将液态水从熔体中分离出来；3)开发触发系统(例如，将气枪对准含有预混料的坩埚或锤子装置)，以诱导分离的水蒸气相破裂，从而使热岩浆和液态水的直接相互作用导致快速冷却并导致火山爆发；以及4)用观测方法测量坩埚，以研究系统的机械和动力学行为(例如，安装在坩埚底部以测量爆炸垂直力的高速力传感器、用于测量熔体温度的坩埚内的热电偶、用于观察喷射的高速照相机)。该设备的开发将涉及咨询德国维尔茨堡大学的科学家，并聘请一名博士生学习仪器系统工程和实验。初始实验将改变预混合参数(注入水的几何形状和体积以及沿坩埚供应坡道下的水的预加载？动态预混料)，测试不同的触发机制和喷射物的后续研究(例如，火山灰矿物的粒度分析、空间分布、质地和矿物学研究)。在实验中，熔体组成将保持不变。爆炸实验将在一个现有的户外设施(纽约州立大学水牛城分校租用的GeoHazards野战站)进行，该野战站已经被允许使用炸药。该装置的拟议规模代表了迄今为止一直通过实验控制以研究云雾作用的岩浆预混合物体积增加两个数量级的可能性，并为研究云雾作用行为和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尺度参数空间。这个实验规模与自然系统的规模相去甚远，但应该会为围绕云雾作用性质的问题提供新的见解，包括：1)当许多水域均匀和不均匀分布时，被困在熔体中的许多水域对爆炸强度有什么影响？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地爆炸？实验结果将提供给试图将实验室观察结果与自然系统行为相适应的模型。*

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.***