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

1347992 SonderThis grant supports the development of an experimental ability to control influencing parameters and study the behavior of phreatomagmatic events.该基金支持控制影响参数和研究蒸汽岩浆事件行为的实验能力的发展。 具体来说，PI将开发一种重要的，迄今尚未开发的，升级的设备，用于控制和观察触发爆炸性蒸汽岩浆火山作用的行为：1）组装和开发一个用于熔化天然火成岩的可倾斜炉;（2）建立25- 50 L隔热坩埚，熔体将被倒入其中，并且通过坩埚的底部，水可以在整个熔体的各个隔离点处注入，以产生蒸汽岩浆的预混料？其中准稳定的水蒸气相将液态水与熔体分离; 3）开发触发系统（例如，指向包含预混物的坩埚中的气枪或锤装置）以引起分离的水蒸气相的破裂使得热岩浆和液态水的直接相互作用引起快速冷却并导致爆发性火山作用;以及4）用观察方法学装备坩埚以研究系统的机械和动力学行为（例如，安装在坩埚底部测量垂直爆炸力的高速力传感器、坩埚内测量熔体温度的热电偶、观察喷出物的高速摄像机）。 该设备的开发将涉及与德国维尔茨堡大学的科学家进行磋商，并聘请了一位博士。仪表系统工程和实验专业学生。 初始实验将改变预混参数（注入水的几何形状和体积以及水沿坩埚供应斜坡的预加载？动态预混合），测试不同的触发机制和随后的喷出物研究（例如，灰分矿物的粒度分析、空间分布、结构和矿物学研究）。 熔体组成将保持为实验常数。 爆炸实验将在一个现存的室外设施（纽约州立大学布法罗分校租用的地质灾害野外站，该设施已被允许用于爆炸物）进行。 建议的规模的设备代表了潜在的两个数量级的增加量的岩浆预混物，迄今为止已经实验控制研究phreatomagmatism，并提出了一个有趣的中尺度参数空间，研究phreatomagmatic行为和条件，有利于有害的灰云和火山碎屑密度电流的形成。 这种实验规模与自然系统的规模相差甚远，但应该为围绕着蒸汽岩浆作用的本质的问题提供新的见解，包括：1）当熔体中包裹的许多水域均匀和不均匀分布时，它们对爆炸强度的影响是什么？2）是否有启动爆炸所需的最低触发能量，或者预混物本身是否能有效地爆炸？ 实验结果将输入模型，试图将实验室观察扩展到自然系统行为。

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.***