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Enhanced Multiscale Boiling Surfaces (EMBOSS): From Fundamentals to Design

增强型多尺度沸腾表面 (EMBOSS)：从基础知识到设计

基本信息

批准号：
EP/S019502/1
负责人：
Tassos Karayiannis
金额：
$ 72.58万
依托单位：
Brunel University London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FS019502%2F1
关键词：
Enhanced Multiscale Boiling Surfaces EMBOSS

项目摘要

Boiling phenomena are central to heating and cooling duties in many industries, such as cooling and refrigeration, power generation, and chemical manufacture. Limitations to boiling heat transfer arise through surface dry-out at high heat flux, leading to localised hot-spots on heat transfer surfaces and larger equipment requirements. Whilst this is a significant problem for many industries, it becomes even more of an issue when dealing with small-scale systems, such as those used for cooling of microelectronics, where failure to remove heat effectively leads to localised overheating and potential damage of components. Spatially non-uniform and unsteady dissipative heat generation in such systems is detrimental to their performance and longevity. The effective heat exchanger area is of order sq. cm, with heat fluxes of order MW/sqm. This requires a transformative, step-change, beyond the current state-of-the-art for cooling heat fluxes between 2-15 MW/sqm at local "hot spots" to prevent burn out.A number of attempts have already been made to extend the upper boundary for the heat flux through alteration of surface characteristics with the aim of improved nucleation of vapour bubbles, bubble detachment, and subsequent rewetting of the surface by liquid. Despite the progress made, previous work on surfaces for pool- (and potentially flow-) boiling does not involve a rational approach for developing optimal surface topography. For instance, nucleate boiling heat transfer (NBHT) decreases with increasing wettability, and the designer must consider the nucleation site density, associated bubble departure diameter, and frequency related to the surface structure and fluid phase behaviour. For high surface wettability, the smaller-scale surface structure characteristics (e.g. cavities) can act as nucleation sites; for low wettability, the cavity dimensions, rather than its topology, will dominate. Therefore, characterising surfaces in terms of roughness values is insufficient to account for the changes in the boiling curve: the fluid-surface coupling must be studied in detail for the enhancement of NBHT and the critical heat flux.EMBOSS brings together a multi-disciplinary team of researchers from Brunel, Edinburgh, and Imperial, and six industrial partners and a collaborator (Aavid Thermacore, TMD ltd, Oxford Nanosystems, Intrinsiq Materials, Alfa Laval, CALGAVIN, and OxfordLasers) with expertise in cutting-edge micro-fabrication, experimental techniques, and molecular-, meso- and continuum-scale modelling and simulation. The EMBOSS framework will inform the rational design, fabrication, and optimisation of operational prototypes of a pool-boiling thermal management system. Design optimality will be measured in terms of materials and energy savings, heat-exchange equipment efficiency and footprint, reduction of emissions, and process sustainability. The collaboration with our partners will ensure alignment with the industrial needs, and will accelerate technology transfer to industry. These partners will provide guidance and advice through the project progress meetings, which some of them will also host. In addition, Alfa Laval will provide brazed heat exchangers as condensers for the experimental work, Intrinsiq will provide copper ink for coating surfaces and Oxford nanoSystems will provide nano-structured surface coatings. The project will integrate the challenges identified by EPSRC Prosperity Outcomes and the Industrial Strategy Challenge Fund in Energy (Resilient Nation), manufacturing and digital technologies (Resilient Nation, Productive Nation), as areas to drive economic growth.

沸腾现象是许多工业中加热和冷却任务的核心，例如冷却和制冷，发电和化学制造。沸腾传热的限制是由于高热通量下的表面干燥，导致传热表面上的局部热点和更大的设备要求。虽然这对许多行业来说都是一个重要的问题，但在处理小规模系统时，例如用于微电子冷却的系统，它变得更加重要，因为无法有效地去除热量会导致局部过热和组件的潜在损坏。在这种系统中，空间上不均匀和不稳定的耗散热产生对其性能和寿命是有害的。有效的热交换器面积是数量级sq。cm，热通量为MW/sqm。这需要一个变革性的、阶跃式的变化，超越了当前最先进的冷却热通量在2-15 MW/sqm之间的局部“热点”，以防止烧坏。已经进行了许多尝试，通过改变表面特性来扩展热通量的上边界，目的是改善蒸汽气泡的成核、气泡分离和随后的液体表面再润湿。尽管取得了进展，以前的工作表面池（和潜在的流动）沸腾不涉及一个合理的方法来开发最佳的表面形貌。例如，核态沸腾传热（NBHT）随着润湿性的增加而降低，设计者必须考虑成核位置密度、相关气泡离开直径以及与表面结构和流体相行为相关的频率。对于高表面润湿性，较小尺度的表面结构特征（例如空腔）可以充当成核位点;对于低润湿性，空腔尺寸而不是其拓扑结构将占主导地位。因此，根据粗糙度值表征表面不足以解释沸腾曲线的变化：为了提高NBHT和临界热通量，必须对流体-表面耦合进行详细的研究。英国皇家科学院的研究人员组成了一个多学科的研究小组，他们来自布鲁内尔大学、爱丁堡大学和帝国理工学院，还有六个工业合作伙伴和一个合作者（Aavid Thermacore、TMD ltd、Oxford Nanosystems、Intrinsiq Materials、Alfa拉瓦尔、CALGAVIN和OxfordLasers）在尖端微制造、实验技术以及分子、介观和连续尺度建模和模拟方面拥有专业知识。该框架将为池沸腾热管理系统的操作原型的合理设计、制造和优化提供信息。设计优化将从材料和能源节约、热交换设备效率和占地面积、减少排放和工艺可持续性方面进行衡量。与我们的合作伙伴的合作将确保与工业需求保持一致，并将加速技术向工业的转移。这些合作伙伴将通过项目进展会议提供指导和咨询意见，其中一些合作伙伴还将主持项目进展会议。此外，Alfa拉瓦尔将提供钎焊热交换器作为实验工作的冷凝器，Intrinsiq将提供用于涂层表面的铜油墨，Oxford nanoSystems将提供纳米结构表面涂层。该项目将整合EPSRC繁荣成果和工业战略挑战基金在能源（弹性国家），制造业和数字技术（弹性国家，生产力国家）方面确定的挑战，作为推动经济增长的领域。