Periodic Structures in Pool Fires

观测到大的旋涡结构在底部形成 中等规模的火灾，并作为燃料向上传播， 空气是相互消耗的。 这项研究旨在了解如何 以及这些结构形成的原因，来量化它们对 空气的夹带和燃料的燃烧速率，以及 识别近场流体的相似性和差异性 池火中的力学原理，强烈浮力的无反应喷射流， 和加热的水平表面上的自然对流。 同时测量的波动 浓度和速度在多个位置内的一个 大的，低速的氦气喷射流垂直地进入空气， 模拟泳池起火 脉动的温度和速度 也高于燃烧的酒精池， 直径为2.5米。 一个三维的，瞬态的数值 非反应系统的模型正在开发，以解释 实验结果。 本研究的结果将提供定量依据 用于预测泳池火灾。 因为它将基于 对中等规模的结果的基本解释 羽流实验，这种理解也将适用于 火灾的规模较大，这是经常关注的， 社区（泄漏、油箱等）。

Large vortical structures have been observed to form at the base of moderate sized fires and to propagate upwards as the fuel and air are mutually consumed. This research seeks to understand how and why these structures form, to quantify their effect on the entrainment of air and the burning rate of the fuel, and to identify the similarities and differences in the near-field fluid mechanics among pool fires, strongly buoyant nonreacting jets, and natural convection above heated horizontal surfaces. Simultaneous measurements are made of the fluctuating concentration and velocity at multiple locations inside a large, low speed helium jet flowing vertically into air to simulate a pool fire. The fluctuating temperature and velocity are measured also above burning alcohol pools up to nearly one meter in diameter. A three-dimensional, transient numerical model of the nonreacting system is being developed to interpret the experimental results. The results of this research will provide a quantitative basis for the prediction of pool fires. Because it will be based on the fundamental interpretation of results from medium-sized plumes experiments, such understanding will be applicable also to fires of larger dimensions, which are of frequent concern to the community (spills, fuel tanks, etc...).