Composite structural housing with integrated thermal management

具有集成热管理功能的复合结构外壳

• 批准号: 2747466
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2747466
• 关键词: Composite; structural; housing; integrated; thermal

As modern rotorcraft design shifts away from conventional power and towards more electrical systems, the need for efficient thermal regulation has never been higher. Systems are currently in place to combat this in rotorcraft but they would benefit from higher integration and optimisation. The key to achieving this may lie in further utilisation of materials that are already commonplace in the aerospace industry; composites. Composite materials, namely carbon and glass fibre reinforced composites (CFRPs/GFRPs) have widespread applications in modern aircraft and can comprise as much as 40-50% of structural components. The prevalence of composite materials is mainly due to their high strength-weight ratio and stiffness tailoring ability. They are however limited in temperature critical areas due to their poor thermal performance. This means they are generally unsuitable for structural applications around components that require a large amount of heat removal. However, if the thermal performance of these composite materials could be improved without compromising the mechanical properties of the material itself, the benefits would be numerous. This project aims to investigate ways to improve the thermal characteristics of composite materials in ways that would aid the removal of heat from temperature critical components. There are currently a few novel concepts that can do this on a small scale, but current literature and research into the area is scarce. This likely means a new technique, or a combination of techniques would have to be used to achieve this. There are two types of techniques that could be used; passive and active cooling. A passively cooled system would employ microstructural or geometric features and take advantage of the surrounding environment to promote heat dissipation without the need for energy consumption. Microstructurally, this may include thermally conductive additives into the composite matrix or improved crystallinity within the matrix. Geometrically, this may involve ventilation features that take advantage of the surrounding conditions and the airspeed produced by the rotors. Possibly the most promising concept however would be to improve thermal conductivity in the through-thickness direction of the composite using z-pinning for tufting (stitching). This would create thermally conductive pathways within the structure with more conductive materials such as carbon or metals. These two techniques already have uses from a mechanical performance perspective, but their thermal effects have not been investigated in research. Preliminary experiments have already been carried out to investigate z-pinning as part of this project, with promising initial results. An actively cooled system would require some means of energy consumption in order to remove heat from the system. This would most easily be done by pumping a cooling fluid around the surface of the structure. Some similar systems exist in the modern rotorcraft but integration into composite structures is very complex. Channels can however be embedded within the composite to create a 'vascular network' through which coolant can be pumped. Based on the limited literature, this technique offers the most potential to achieve the cooling effect required, and will form the bulk of the experimental work of this project. The size, configuration, and fabrication method of the channels are all factors that need to be investigated further, as well as choice of coolant and flow velocity. These variables will create a strong starting point for research. The project will use a two pronged approach to evaluate both passive and active systems experimentally, before identifying the concept with the highest potential. This concept will then be evaluated in more detail and with a specific application in mind, in the hopes of raising the TRL level and furthering the research for future projects.

随着现代旋翼机的设计从传统动力转向更多的电气系统，对有效的热调节的需求从未像现在这样高。目前旋翼机上已经有了应对这一问题的系统，但它们将受益于更高的集成度和优化。实现这一目标的关键可能在于进一步利用在航空航天工业中已经很常见的材料：复合材料。复合材料，即碳纤维和玻璃纤维增强复合材料(CFRPs/GFRPs)在现代飞机上有着广泛的应用，可占结构部件的40%-50%。复合材料的流行主要是因为它们具有较高的强度重量比和刚度剪裁能力。然而，由于其较差的热性能，它们在温度关键区域受到限制。这意味着它们通常不适合需要大量散热的组件周围的结构应用。然而，如果这些复合材料的热性能能够在不损害材料本身机械性能的情况下得到改善，好处将是不计其数的。该项目旨在研究如何改善复合材料的热特性，以帮助从温度关键部件中排出热量。目前有一些新的概念可以在小范围内做到这一点，但目前对这一领域的文献和研究很少。这可能意味着必须使用一种新的技术，或者多种技术的组合来实现这一点。可以使用两种类型的技术：被动冷却和主动冷却。被动冷却系统将利用微结构或几何特征，并利用周围环境来促进散热，而不需要消耗能源。在微观结构上，这可能包括在复合基质中加入导热添加剂或改善基质中的结晶度。从几何上讲，这可能涉及到利用周围条件和转子产生的空速的通风功能。然而，最有希望的概念可能是使用Z钉扎(缝合)来提高复合材料在贯穿厚度方向的导热系数。这将在结构内用更多的导电材料，如碳或金属，创建热传导路径。从机械性能的角度来看，这两种技术已经有了用途，但它们的热效应还没有在研究中得到研究。作为该项目的一部分，已经进行了初步实验来研究z钉扎，初步结果令人振奋。主动冷却系统需要一些能源消耗手段才能从系统中排出热量。要做到这一点，最容易的方法是在结构表面周围泵入冷却液。现代旋翼机中存在一些类似的系统，但集成到复合材料结构中非常复杂。然而，通道可以嵌入到复合材料中，以创建一个可以泵送冷却剂的“血管网络”。根据有限的文献，这项技术最有可能达到所需的降温效果，并将构成该项目的大部分实验工作。通道的尺寸、结构和制造方法都是需要进一步研究的因素，以及冷却剂和流速的选择。这些变量将为研究创造一个强有力的起点。该项目将使用双管齐下的方法来对被动和主动系统进行实验评估，然后确定具有最高潜力的概念。然后将对这一概念进行更详细的评估，并考虑到具体的应用，希望提高TRL水平，并为未来的项目进一步研究。