Volcanic ash in jet engines: bouncing, sticking, and spreading of molten glass droplets

被吸入喷气发动机的火山灰迅速融化，形成粘性硅酸盐液体液滴，这可能会在高速下冲击发动机表面。根据颗粒流变性、冲击速度、冲击角和涡轮机表面的材料特性，液滴可能会反弹或粘连和扩散。水滴粘在一起是有问题的，因为它会堵塞涡轮叶片内的冷却管道，导致灾难性的发动机故障。这个项目将使用实验室实验和理论分析来研究熔融的玻璃液滴从高温表面反弹、附着和扩散的条件。实验将使用高温熔融硅酸盐玻璃和常温模拟材料。这项研究将利用大量与工业相关的液滴(例如喷雾涂层、喷墨打印)的文献，并将其扩展到与喷气发动机内部相关的设备。该项目将产生对液滴行为的新的定量了解，这将支持项目合作伙伴罗尔斯-罗伊斯的工作，以确定大气火山灰装载和火山灰特征(形状、成分、粒度分布)的关键条件，在这些条件下，空域可以保持开放。

Volcanic ash that is ingested into jet engines melts rapidly to form droplets of viscous silicate liquid, which may impact engine surfaces at high speed. Droplets may bounce, or stick and spread, depending on particle rheology, impact velocity, impact angle, and the material properties of the turbine surfaces. Sticking of droplets is problematic because it can block the cooling ducts within turbine blades, leading to catastrophic engine failure. This project will use laboratory experiments and theoretical analysis to investigate the conditions under which molten glass droplets bounce off, stick to, and spread across hot surfaces. Experiments will use both high temperature molten silicate glasses and ambient temperature analogue materials. The study will draw on the extensive literature on industrially-relevant droplets (e.g. spray coating, inkjet printing) and extend it to regimes relevant to jet engine interiors. The new, quantitative understanding of droplet behaviour that this project will produce will support work by project partner Rolls-Royce to determine critical conditions of atmospheric ash loading and ash characteristics (shape, composition, size distribution) beneath which airspace can remain open.