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Evolution and dynamics of pellets and dust in dynamic gas-plasma systems

动态气体等离子体系统中颗粒和灰尘的演化和动力学

基本信息

批准号：
EP/N018117/1
负责人：
Declan Diver
金额：
$ 43.93万
依托单位：
University of Glasgow
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FN018117%2F1
关键词：
Evolution dynamics pellets dust dynamic

项目摘要

Nuclear fusion offers the prospect of almost limitless power production with minimal environmental impact. Magnetic fusion in tokamaks (which are magnetic chambers that can hold plasma at a temperature in excess of that in the solar core) has demonstrated a practical route to power generation via JET, and the construction of the next generation of fusion power station, ITER, is well under way. Key elements in the realisation of practical fusion power are (i) maintaining plasma stability, and (ii) refuelling the reactor. The injection of cryogenically solid fuel pellets offers a way to address both aspects: these icy pellets of Deuterium-Tritium mixture are fired at speeds of up to 300m/s into the burning fusion plasma in order to replenish spent fuel, and also to drive the density profile across the plasma, so aiding the stability of the burning process. The evolution of the pellet as it encounters the energetic plasma presents technical challenges, demanding stringent modelling in order to optimise the process. The pellet evaporates under the intense bombardment of the energetic fusion plasma, shedding fuel gas in clouds along its trajectory. These clouds become ionized and polarized (charge-separated) as part of the process of equilibrating with the pre-existing reactor plasma, and at the same time the pellet also becomes charged; complex electromagnetic and fluid forces then determine the density deposition profile as the pellet trajectory evolves from being purely ballistic (ie with trajectory governed by initial conditions at launch) to a more sophisticated dynamics. Moreover, the response of the existing plasma to the new material affects the reactor conditions, and accounting for the transient feedback (over a few milliseconds) in both directions is a challenging problem. This research proposal aims to create new modelling of the evaporation, ionization and fluid/electromagnetic feedback on both the plasma conditions and the pellet evolution by exploiting new techniques in handling gas-magnetized plasma momentum and energy exchanges, and ionization mechanisms. By so doing, it is hoped that this proposed research can address gaps in the current approaches, and assist in the creation of a new, optimised design of pellet refuelling and stability for tokamaks. The impact of this science is broader than the immediate technological goal of carbon-free energy production: similar plasma-solid interface physics occurs in many situations, from cometary impact on stellar atmospheres to plasma catalysis and gas remediation. Indeed, there are many circumstances in which plasma impacting directly or indirectly onto a surface can promote beneficial changes to that surface, such as making it waterproof (hydrophobic) or biocidal (inhibiting bacterial attachment) or laying down new surface coatings (plasma vapour deposition). Though the analysis and modelling of frozen pellets for fusion may not seem initially to be relevant to these areas, there is major scope to explore whether or not small droplets or pellets in suspension may provide advantages over classical plasma processing techniques in applications such as coatings or catalysis; the insight offered by the research proposed here will be key to evaluating these new potential uses.

核聚变提供了几乎无限的电力生产和最小的环境影响的前景。托卡马克（一种可以将等离子体保持在高于太阳核心温度的磁室）中的磁聚变已经证明了通过JET发电的可行途径，下一代聚变发电站ITER的建设正在顺利进行。实现实用聚变能的关键要素是：（i）保持等离子体稳定性;（ii）给反应堆加燃料。低温固体燃料芯块的注入提供了一种解决这两个方面的方法：这些氘-氚混合物的冰冷芯块以高达300米/秒的速度被发射到燃烧的聚变等离子体中，以补充乏燃料，并驱动整个等离子体的密度分布，从而帮助燃烧过程的稳定性。颗粒在遇到高能等离子体时的演变提出了技术挑战，需要严格的建模以优化工艺。小球在高能聚变等离子体的强烈轰击下蒸发，沿着其轨迹以云的形式脱落燃料气体。这些云成为电离和极化（电荷分离）作为与预先存在的反应堆等离子体平衡的过程的一部分，同时弹丸也变得带电;复杂的电磁力和流体力然后决定了密度沉积曲线，因为弹丸轨迹从纯粹的弹道（即由发射时的初始条件决定的轨迹）演变为更复杂的动力学。此外，现有等离子体对新材料的响应会影响反应堆条件，并且在两个方向上解释瞬态反馈（超过几毫秒）是一个具有挑战性的问题。这项研究提案旨在通过利用处理气体磁化等离子体动量和能量交换以及电离机制的新技术，建立蒸发，电离和流体/电磁反馈对等离子体条件和颗粒演化的新模型。通过这样做，希望这项拟议的研究可以解决目前方法中的差距，并有助于创建一个新的，优化的托卡马克颗粒换料和稳定性设计。这一科学的影响比无碳能源生产的直接技术目标更广泛：类似的等离子体-固体界面物理学发生在许多情况下，从彗星对恒星大气的影响到等离子体催化和气体修复。事实上，在许多情况下，等离子体直接或间接地冲击到表面上可以促进该表面的有益变化，例如使其防水（疏水）或杀生物（抑制细菌附着）或铺设新的表面涂层（等离子体气相沉积）。虽然用于聚变的冷冻颗粒的分析和建模最初似乎与这些领域无关，但有很大的空间来探索悬浮液中的小液滴或颗粒是否可以在涂层或催化等应用中提供优于经典等离子体处理技术的优势;这里提出的研究所提供的见解将是评估这些新的潜在用途的关键。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Critical Velocity Ionization in Substellar Atmospheres

亚恒星大气中的临界速度电离

DOI：
10.3847/1538-4357/ab5800
发表时间：
2019
期刊：
The Astrophysical Journal
影响因子：
0
作者：
Wilson A
通讯作者：
Wilson A

Modelling nonlinear electrostatic oscillations in plasmas

模拟等离子体中的非线性静电振荡

DOI：
10.1063/1.4968520
发表时间：
2016
期刊：
Physics of Plasmas
影响因子：
2.2
作者：
Diver D
通讯作者：
Diver D

Atmospheric Electrification in Dusty, Reactive Gases in the Solar System and Beyond

DOI：
10.1007/s10712-016-9361-7
发表时间：
2016-01
期刊：
Surveys in Geophysics
影响因子：
4.6
作者：
Christiane Helling;R. Giles Harrison;F. Honary;D. Diver;K. Aplin;I. Dobbs-Dixon;U. Ebert;S. Inutsuka;F. Gordillo‐Vázquez;S. Littlefair
通讯作者：
Christiane Helling;R. Giles Harrison;F. Honary;D. Diver;K. Aplin;I. Dobbs-Dixon;U. Ebert;S. Inutsuka;F. Gordillo‐Vázquez;S. Littlefair

Alfvén ionization in an MHD-gas interactions code

MHD-气体相互作用代码中的阿尔文电离