GOALI: Fundamental Studies on High Impact Pressure, Supersonic Water Droplets for Material Deformation and Removal

GOALI：高冲击压力、超音速水滴材料变形和去除的基础研究

• 批准号: 1462993
• 负责人: Brad Kinsey
• 金额: $ 30万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1462993&HistoricalAwards=false
• 关键词: GOALI; Fundamental; Studies; Impact; Pressure

Ultra high pressure, high velocity continuous columns of water jets are used in a number of applications, e.g., as a carrier for grit in water jet cutting of metals. Under ideal conditions, the water pressure of the jet is equal to the pressure head generated by the pump. However, past research has shown that the breakup of the stream into droplets produces impact pressures that significantly exceed the water-hammer pressure. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research into droplet formation and droplet-surface interaction phenomena. Results from this research can help achieve their applications from peening to coating removal to machining in a more economical and environmentally friendly manner. This will benefit society at large by creating environmentally friendly processes with significantly less water usage and contaminated materials compared to competing technologies. Objectives of this research are to (1) assess the effect of various process parameters, i.e., co-flow gas velocity, partial chamber pressure, high frequency instability triggering, and reduced Weber number on droplet formation; (2) determine the droplet characteristics, i.e., droplet velocity, diameter, and spacing, that are required to create the desired droplet-surface interaction results (e.g., residual stresses, surface roughness, or material removal rate); (3) characterize the material behavior and triaxial stress failure mechanisms at high deformation rates; and (4) implement a multi-jet system that can process large surface areas and study additional process parameters, i.e., jet spacing and individual jet pressure. The tools that will be used in this research are (i) an experimental set-up which includes measurement of key process parameters, i.e., visualized droplet characteristics listed above, droplet force, and temperature; and (ii) a suite of predictive finite element models that capture the droplet-surface interaction results. The methodologies used will be both experimental (to allow process parameters to be controlled, measured, and explored) and numerical with validated models (to allow further investigation of the design space compared to simply a trial-and-error experimental approach). The knowledge gained from this research will also benefit the study of other physical phenomena, e.g., cavitation erosion. The academic, industrial, and national laboratory partners have significant expertise in fluid dynamics and solid mechanics modeling, experimental methods, material characterization, machine development, and manufacturing, pertinent to assuring the success of this research.

超高压、高速连续水射流柱在许多应用中都有应用，例如，在金属水射流切割中作为砂砾的载体。在理想条件下，射流的水压等于泵产生的压头。然而，过去的研究表明，水流破碎成水滴产生的冲击压力远远超过水锤压力。这项学术与工业联络资助机会（GOALI）奖支持对液滴形成和液滴表面相互作用现象的基础研究。这项研究的结果可以帮助以更经济和环保的方式实现从喷丸到涂层去除到加工的应用。与竞争技术相比，这将创造更少用水和污染材料的环境友好型工艺，从而使整个社会受益。本研究的目的是：(1)评估共流气体速度、分腔压力、高频不稳定触发和减少韦伯数等工艺参数对液滴形成的影响；(2)确定液滴特性，即液滴速度、直径和间距，这些都是产生所需的液滴-表面相互作用结果（例如，残余应力、表面粗糙度或材料去除率）所必需的；(3)表征了高变形速率下材料的性能和三轴应力破坏机制；(4)实现一个多射流系统，该系统可以加工大表面积，并研究附加工艺参数，即射流间距和单个射流压力。本研究将使用的工具是：(i)实验装置，包括关键工艺参数的测量，即上面列出的可视化液滴特性，液滴力和温度；（ii）一套预测有限元模型，捕捉液滴表面相互作用的结果。所使用的方法将是实验性的（允许控制，测量和探索工艺参数）和经过验证的模型的数值（允许进一步调查设计空间，而不是简单的试错实验方法）。从这项研究中获得的知识也将有利于其他物理现象的研究，例如，空化侵蚀。学术、工业和国家实验室合作伙伴在流体动力学和固体力学建模、实验方法、材料表征、机器开发和制造方面具有重要的专业知识，这与确保这项研究的成功有关。