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Characterization of the Physics and Chemistry of the Blue Whirl for Clean Combustion

清洁燃烧蓝旋的物理和化学表征

基本信息

批准号：
1839510
负责人：
Carolyn Kaplan-Solomond
金额：
$ 26万
依托单位：
University of Maryland, College Park
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1839510&HistoricalAwards=false
关键词：
Characterization Physics Chemistry Blue Whirl

项目摘要

This project is inspired by the blue whirl, a small, spinning blue flame that was first observed when it evolved naturally from a fire burning a liquid fuel puddle poured onto the top of a flat pan filled with water. Once the blue whirl forms, it remains in the steady, stable, completely blue state, in which no soot is formed. Once it forms, all of the turbulence in the original fire disappeared and the spinning top burned silently until there was no fuel remaining on the water. Since its discovery, there has been considerable theoretical conjecture about what this flame actually is, how it evolves, and how, if at all, it could be useful. Experiments have provided many clues. For example, almost any liquid hydrocarbon including crude oil, can create the blue whirl, it can be made on a smooth metal pan with no water, and the temperature in the purple haze at the top of the flame is very hot at 2000K. What is needed, however, is an understanding of the fluid dynamics and chemistry leading to and controlling the blue whirl. What is needed to further this understanding is a simulation that will show how the flame evolves and provide some guidance to experiments and theoretical analyses. This blue flame could potentially inspire an ideal burner that consumes any liquid fuel with no soot and minimal pollution.The objective of this proposal is to create a numerical model capable of simulating the blue whirl, from its inception as a small fire, through to the evolution into a fire whirl, then through the complex transition to the blue whirl. This is a complex physical and chemical problem involving evaporation of liquid fuel, formation of a fire whirl, and then the dynamic vortex breakdown of the fire whirl that leads to the blue whirl. The most stringent requirement of this model is that it must be optimized so that it can perform enough simulations to explore the physicochemical parameter space of the liquid-burning fire whirl and blue whirl. To accomplish this, it will be necessary to have a model that solves the governing reactive-flow conservation equations and adequately resolves the fluid dynamics, chemical reactions and energy release, heat and mass diffusion, and perhaps the multiphase problem of hydrocarbon liquid evaporation. The numerical model must be capable of simulating hydrocarbon flames through a range of stoichiometric from lean to rich. To accomplish this objective, a three-dimensional unsteady fluid model that allows transitions from flow regimes of incompressible to fully compressible flows, based on the barely implicit correct to flux-corrected transport, will be developed and tested. In addition, a chemical-diffusive model will be developed for liquid fuels and tested for diffusion flames. Intermediate steps in the project include simulations of fire whirls for benchmarks and three-dimensional vortex breakdown in compressible gases.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这个项目的灵感来自蓝色漩涡，一个小的，旋转的蓝色火焰，第一次被观察到时，它自然地从火燃烧液体燃料水坑倒在一个平底锅的顶部充满水。一旦蓝色漩涡形成，它就会保持稳定，稳定，完全蓝色的状态，在这种状态下不会形成烟灰。一旦它形成，原始火焰中的所有湍流都消失了，旋转的顶部无声地燃烧，直到水面上没有剩余的燃料。自从它被发现以来，关于这种火焰实际上是什么，它是如何演变的，以及它如何有用，已经有了相当多的理论猜测。实验提供了许多线索。例如，几乎任何液体碳氢化合物，包括原油，都可以产生蓝色漩涡，它可以在光滑的金属锅上不加水，火焰顶部紫色薄雾的温度非常高，达到2000 K。然而，我们需要的是对导致和控制蓝色漩涡的流体动力学和化学的理解。进一步理解这一点所需要的是一个模拟，它将显示火焰是如何演变的，并为实验和理论分析提供一些指导。这种蓝色火焰可能会激发出一种理想的燃烧器，它消耗任何液体燃料，没有烟尘，污染最小。本提案的目标是创建一个能够模拟蓝色漩涡的数值模型，从一开始的小火，通过演变成火漩涡，然后通过复杂的过渡到蓝色漩涡。这是一个复杂的物理和化学问题，涉及液体燃料的蒸发，火旋风的形成，然后火旋风的动态涡流破裂，导致蓝色旋风。该模型最严格的要求是必须进行优化，以便能够进行足够的模拟，以探索液体燃烧的火旋风和蓝色旋风的物理化学参数空间。为了实现这一点，有必要有一个模型，解决了控制反应流守恒方程，并充分解决了流体动力学，化学反应和能量释放，热量和质量扩散，也许烃类液体蒸发的多相问题。数值模型必须能够模拟碳氢化合物火焰通过从贫到富的化学计量的范围。为了实现这一目标，将开发和测试一个三维非定常流体模型，该模型允许从不可压缩流到完全可压缩流的流态过渡，该模型基于几乎隐式的校正到通量校正的传输。此外，还将为液体燃料开发一个化学扩散模型，并对扩散火焰进行测试。该项目的中间步骤包括为基准和可压缩气体中的三维涡破裂模拟火旋风。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。