Gonzalez-Avila Silvestre Roberto, Nguyen Dang Minh, Arunachalam Sankara, Domingues Eddy M, Mishra Himanshu, Ohl Claus-Dieter
Department for Soft Matter, Institute for Physics, Otto-von-Guerick University, 39106 Magdeburg, Germany.
School of Physical and Mathematical Sciences, Department of Physics and Applied Physics, Nanyang Technological University, Singapore 637371, Singapore.
Sci Adv. 2020 Mar 27;6(13):eaax6192. doi: 10.1126/sciadv.aax6192. eCollection 2020 Mar.
Cavitation refers to the formation and collapse of vapor bubbles near solid boundaries in high-speed flows, such as ship propellers and pumps. During this process, cavitation bubbles focus fluid energy on the solid surface by forming high-speed jets, leading to damage and downtime of machinery. In response, numerous surface treatments to counteract this effect have been explored, including perfluorinated coatings and surface hardening, but they all succumb to cavitation erosion eventually. Here, we report on biomimetic gas-entrapping microtextured surfaces (GEMS) that robustly entrap air when immersed in water regardless of the wetting nature of the substrate. Crucially, the entrapment of air inside the cavities repels cavitation bubbles away from the surface, thereby preventing cavitation damage. We provide mechanistic insights by treating the system as a potential flow problem of a multi-bubble system. Our findings present a possible avenue for mitigating cavitation erosion through the application of inexpensive and environmentally friendly materials.
空化现象是指在高速流动中，如船舶螺旋桨和泵等，靠近固体边界处蒸汽泡的形成与溃灭。在此过程中，空化气泡通过形成高速射流将流体能量集中在固体表面，导致机械损坏和停机。对此，人们探索了许多表面处理方法来抵消这种影响，包括全氟涂层和表面硬化，但最终它们都会屈服于空蚀。在此，我们报道了一种仿生气体捕获微纹理表面（GEMS），该表面在浸入水中时，无论基材的润湿性如何，都能牢固地捕获空气。至关重要的是，腔内空气的捕获将空化气泡从表面排斥开，从而防止空化损伤。我们将该系统视为多气泡系统的势流问题，从而提供了机理见解。我们的研究结果为通过应用廉价且环保的材料减轻空蚀提供了一条可能的途径。
