基于计算流体动力学CFD技术的局部反循环打捞工具数值模拟及结构优化

针对现有局部反循环打捞工具存在打捞对象单一、反循环能量不足、碎屑采集率低等问题,提出了一种集收集和打捞于一体的新型局部反循环打捞工具,采用计算流体动力学(CFD)对该型工具作业时的流场进行模拟,揭示该型工具形成反循环的机理。在此基础上,开展该型工具结构优化数值模拟研究。结果表明:该型局部反循环打捞工具利用喷嘴形成的高压水射流的卷吸作用形成反循环系统,适当增加喷嘴数量能够提升该型工具的性能;局部反循环打捞工具性能随着喷嘴直径增加呈现先增大后减小的趋势,继续增大喷嘴直径将导致无法形成有效反循环系统;改变喷嘴的几何形状会影响局部反循环打捞工具性能,采用圆锥形喷嘴的局部反循环打捞工具性能最强,但是所需排量较大。研究结果可为局部反循环打捞工具的优化设计提供参考,为局部反循环打捞工具现场作业提供理论指导。

Numerical simulation and structure optimization of a local reverse-circulation fishing tool based on computational fluid dynamics technology

To solve the problems of single fishing object, insufficient reverse-circulation energy and low debris recovery rate of existing local reverse-circulation fishing tools, a new local reverse-circulation fishing tool, which integrates collection and fishing, is proposed. The flow field of the tool is simulated by computational fluid dynamics (CFD), and the mechanism of reverse-circulation formation of the tool is revealed, on the basis of which the numerical simulation of the tool structure optimization is carried out. The results show that the reverse-circulation system is formed by the entrainment of the high pressure water jet formed by the nozzle, and the performance of the tool can be improved by increasing the number of nozzles appropriately. The performance of the local reverse-circulation fishing tool increases first and then decreases with the increase of the nozzle diameter, and further increasing the nozzle diameter results in the failure to form an effective reverse-circulation system. The change of nozzle geometry affects the performance of the local reverse-circulation fishing tool, which is the best with a conical nozzle, but the required displacement is relatively large. The research results can provide reference for the optimization design of local reverse-circulation fishing tools and theoretical guidance for the on-site operation of local reverse-circulation fishing tools.