Understanding and Controlling Hydrodynamic Cavitation to Improve Manufacturing Processes Involving High Velocity Fluid Flow

该基金支持在制造业领域贡献新知识的研究，促进科学和工程的进步，促进国家繁荣。流体动力空化是指在快速流动的流体中气泡的形成、生长和破裂。由此产生的气泡内爆以压力波或高速微射流的形式释放出集中的能量。这个项目的影响是多方面的；在制造过程中减少总能源消耗的潜力，提高生产零件的质量，并制造出传统制造工艺难以实现的零件特征。从该项目中获得的知识也可用于提高现有空化系统在制造业以外的其他领域的效率，如清洁设备、水净化、工业和食品的均质化。本项目的实验和分析工作为参与研究的研究生和本科生提供了良好的教育机会。该项目特别强调妇女和少数民族学生的参与。该项目还支持制造课程中的几个课堂教学倡议。该项目的目标是促进对制造过程中高速流体流产生流体动力空化机制的基本理解，以便利用这种空化产生的压力波和微射流来增强该过程。采用实验、分析和数值模拟相结合的方法，研究了水动力空化产生和控制的不同机制。该研究包括(1)通过在不同共振频率下的新型流动诱导振动来表征流体动力空化强度，(2)表征可以产生连续和完全空化流体流从而增加可收获能量的涡流，以及(3)开发通过叠加压力波来产生自共振流的机制，旨在提高泡崩溃频率。分析模型提供了气泡破裂时产生的压力的估计，而数值模型提供了描述流体域中空化分布行为的场变量。为了量化从上述机制获得的空化功率密度，从样品中测量的残余应力和显微硬度分布与数值和解析模型中的场变量进行了映射。该项目旨在建立一个知识库，以促进空化能的利用，以提高涉及高速流体流动的制造工艺，如水射流切割、表面处理的水射流强化、纳米润滑剂配方和抛光。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant supports research that contributes new knowledge in the manufacturing field, promoting both progress of science and engineering and advancing national prosperity. Hydrodynamic cavitation is the formation, growth, and burst of gas bubbles in a rapidly flowing fluid. The resulting implosion of gas bubbles releases concentrated energy as pressure waves or high-speed micro jets. The impact of this project is on multiple fronts; the potential to reduce total energy spent in manufacturing processes, increase in the quality of the produced parts and fabrication of part features that are difficult to achieve with conventional manufacturing processes. The knowledge gained from this project could also be used to enhance the efficiency of existing cavitation-based systems in other areas beyond manufacturing such as cleaning devices, water purification, and homogenization of industrial and food products. The experimental and analytical work emanating from this project provides excellent educational opportunities to graduates and undergraduate students participating in the research. Particular emphasis is placed on engaging women and minority students in this project. The project also supports several classroom teaching initiatives within the manufacturing curriculum.The goal of this project is to advance the fundamental understanding of mechanisms for producing hydrodynamic cavitation from a high velocity fluid stream in a manufacturing process so that the pressure waves and micro-jets produced by this cavitation could be utilized to enhance the process. A combination of experimentation and analytical and numerical modeling is used to study different mechanisms for producing and controlling hydrodynamic cavitation. The study includes (1) characterization of hydrodynamic cavitation intensity via novel flow-induced vibration at various resonance frequencies, (2) characterization of vortex flows that can generate continuous and fully cavitating fluid streams thus increasing the yield on the energy to be harvested, and (3) development of mechanisms for creating self-resonating flows via superposition of pressure waves aimed at enhancing bubble collapse frequency. The analytical modeling provides an estimate of pressure induced during bubble collapse, whereas numerical modeling provides field variables depicting distribution behavior of cavitation in the fluid domain. To quantify the cavitation power density obtained from the above mechanisms, residual stresses and microhardness distributions measured from samples are mapped with field variables from numerical and analytical models. This project is aimed at creating a knowledge base to facilitate utilization of the cavitation energy to enhance manufacturing processes that involve high velocity fluid flow such as water jet cutting, water jet peening for surface treatment, nano-lubricant formulation, and polishing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.