超长航程水下滑翔机仿生表面功能特性实验研究

The underwater glider is a new type of unmanned underwater vehicle system, which can conduct a long-term and large-range observation and detection task in the complex ocean environment. According to the design requirements for the super-long-voyage domestic underwater glider successfully self-developed by China, in this study, the functional characteristics of bionic surfaces will be experimentally investigated based on its strategy design of the underwater glider for drag reduction. The bionic surfaces include the shark-skin-inspired riblets and bionic superhydrophobic anodic Titania Nanotubes. The time and space response mechanism of the near-wall flow to the bionic surfaces at the maximum drag-reduction point will be revealed under different environmental conditions, i.e., under the similar conditions of high pressure in the deep sea, which may be as a result of the Kelvin-Helmholtz instability mechanism. Furthermore, two technical difficulties, i.e., its design parameters optimization and solidifying of the biomimetic surface feature of the compressive cabin, will be conquered. Meanwhile, the comprehensive efficiency rate of the piping system of the buoyancy-driven unit of underwater glider will be promoted from about 35% to 40%. An engineering prototype of the super-long-voyage underwater glider with independent intellectual property rights will be designed and manufactured, whose compressive cabin will be equipped with the shark-skin-inspired riblets or with bionic superhydrophobic anodic Titania nanotubes which can be easily replaced as needed. Moreover, its pipeline system of the buoyancy-driven unit will be working at a maximum working efficiency whose internal surface is produced by bionic superhydrophobic anodic Titania nanotubes as well. Lastly, the drag reduction performance of the engineering prototype will be verified by sea trial for a super-long-voyage supported by the theories and technologies.

水下滑翔机作为一种新型的水下无人航行器系统平台，可实现对于复杂海洋环境长时续、大范围的观测与探测。面向我国自主研制成功的国产水下滑翔机超长航程的设计需求，本项目基于水下滑翔机减阻策略设计，对仿生表面（含仿生沟槽和仿生超疏水纳米孔阵列涂层）功能特性进行实验研究，将揭示近壁流场在不同环境条件下,特别是高压力深海工作条件下，对仿生表面减阻极限点的时-空响应机制，即近壁流场可能的“开尔文-亥姆霍兹”失稳响应机制；优化设计及其固化壳体仿生表面特征形貌参数，同时通过管路内部镀刻最优参数的仿生超疏水纳米孔阵列涂层实现水下滑翔机浮力驱动单元管路系统综合效率的提升;并探索仿生表面高压力深海工作条件下层流/湍流减阻机理，为“壳体设计加工有仿生表面（两类壳体可模块化替换）且浮力驱动单元管路系统内部镀有最优参数仿生超疏水纳米孔阵列涂层”的超长航程水下滑翔机的设计研发和海上试验功能验证提供理论和技术支撑。

水下滑翔机是一种新型智能无人潜航器，可对海洋环境参数进行大范围、长时序地自主观测与探测，对海洋科学研究与安全保障具有重要意义与应用价值。本项目面向超长航程水下滑翔机的设计与应用需求，对仿生表面减阻、抗压及其防生物附着等功能特性进行了基础理论和相关技术试验研究，同时结合团队国家重点研发计划项目任务，开展了长航程水下滑翔机样机极限能力海上试验验证，完成的研究内容包括水下滑翔机高压深海作业环境下的壳体仿生（低表面能）表面减阻技术及其机理，以及其浮力驱动单元管路系统仿生超疏水纳米孔阵列涂层减阻技术及其机理研究等2个主要方面。执行期内，项目研究在关键技术指标突破、科学问题解决和知识成果产出等3个主要方面取得重要进展：在技术指标突破方面，1）形成了壳体可模块化替换的水下滑翔机工程样机1台，“海燕-L”号，其设计航程超过5000公里，实际海上试验最远达5506公里；2）该新型水下滑翔机样机浮力驱动系统综合效率提升至65%以上。在科学问题解决方面，1）风洞内PIV试验证明了平板沟槽表面减阻至极限点时流场的时-空响应机制是Kelvin-Helmholtz-like不稳定现象，该现象同样在水下高速航行器非回转体壳体表面流场的模拟结果中也被观察到，是超空泡减阻至极限点的可能原因之一；2）在壳体仿生表面特征形貌参数最优即实现其对表面流场最优调制时，从流场相干结构发展演化的视角，初步探索了其层流/湍流外流减阻的机理；3）通过CFD和压力降试验对管路内部仿生超疏水纳米孔阵列涂层微纳结构参数进行优化，探索刻画出了一定压力条件下仿生表面层流/湍流内流减阻的规律。重要成果产出方面，1）获得授权相关发明专利2项，申请PCT专利1项，获批软件著作权1项；2）发表期刊论文11篇，会议论文4篇；和团队成员合作撰写学科规划类图书篇章1篇；3）和团队一起获批立项并完成行业标准2项；获行业奖励1项，省部级以上奖励3项；培养毕业研究生14名；作为首席科学家，获批国家重点研发计划项目1项。