MRI: Track 1 Acquisition of Spray Particle & Spray Droplet Size Analyzer for Precision Manufacturing

该主要研究仪器（MRI）奖支持购买用于精密制造技术和半导体技术的喷雾颗粒和喷雾液滴尺寸分析仪。制造中的磨削操作会产生大量的热量，这可能会对正在制造的部件造成损坏。冷却剂必须输送到磨削表面，但这种冷却剂很容易与空气混合，导致效果较差。喷雾颗粒和喷雾液滴尺寸分析仪将提供磨削过程中冷却剂射流破裂的测量，并将改进冷却剂喷嘴设计和冷却剂输送建模。该仪器将能够研究各种材料，包括那些难以研磨和难以散热的材料，以及冷却剂的性能。冷却的改进将减少环境中的热污染，这在磨削行业是实质性的。该仪器还将能够评估和减轻油基冷却剂的扩散和油雾的形成，这种油雾在吸入时具有火灾危险和安全隐患。该仪器将加强阿克伦大学精密制造中心的研究和培训，并使俄亥俄州东北部地区受益，该地区拥有超过30%的俄亥俄州制造业工人。受益于该仪器的学生，包括那些来自工程领域代表性不足的社区的学生，将获得实践培训和知识，涵盖流体动力学和传热基础知识，以满足制造业和半导体行业的需求。如果磨削过程中产生的热量管理不当，可能会导致热损伤，如拉伸残余应力、变色、软化、再硬化和裂纹。相干（层流）射流提供冷却流体输送，在接触区提供最大的润滑，这对于在高材料去除率下进行无缺陷磨削至关重要。湍流射流扩散不允许冷却剂射流有效地突破高速空气边界层-由空气沿快速旋转的砂轮表面夹带产生-并进入热轮-工件界面。喷射冷却剂输送到磨削区的程度是未知的。喷雾颗粒和喷雾液滴尺寸分析仪将使人们更好地理解流体射流在各种工作条件下的层流到湍流的转变。相干冷却剂射流的解体和向湍流过渡的数值模拟是使用该仪器验证射流破裂数值模型需要克服的挑战。精确模拟冷却液射流相干性的能力是金属加工领域潜在的游戏规则改变者。为了验证数值模型，将利用该仪器对制造的喷嘴进行实验研究。此外，冷却剂中颗粒的存在会导致喷嘴的污染，从而影响射流的解体。射流相干性的评估以及射流中粒子的量化将有助于预测是否需要更换喷嘴。通过使用所获得的仪器研究射流破裂，选择冷却射流参数以确保射流的相干性。该项目由民用、机械和制造创新部（CMMI）的主要仪器研究计划（MRI）和先进制造计划（AM）共同资助。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 Major Research Instrumentation (MRI) award supports the acquisition of a spray particle and spray droplet size analyzer for precision manufacturing technology and semiconductor technology. Grinding operations in manufacturing produce substantial heat which can cause damage to the component being made. Coolant must be delivered to the grinding surface, but this coolant can be easily mixed with air causing is to be less effective. The spray particle and spray droplet size analyzer will provide measurements of the break-up of a coolant jet during grinding and will enable improved coolant nozzle design and coolant delivery modeling. This instrument will enable research on variety of materials, including those that are hard-to-grind and hard to dissipate heat, and coolant properties. Improvements in cooling will reduce heat pollution in the environment, which is substantial in the grinding industry. The instrument will also enable evaluation and mitigation of the spread of oil-based coolant and formation of oil mist that represents a fire hazard and safety hazard when inhaled. The instrument will enhance research and training in the Center for Precision Manufacturing at the University of Akron and benefit the Northeastern Ohio region which is home to over 30% of the State of Ohio’s manufacturing workers. The students who will benefit from the instrument, including those from communities under-represented in engineering, will gain hands-on training and knowledge spanning fundamentals of fluid dynamics and heat transfer to the needs of the manufacturing and semiconductor industries.If the heat produced during grinding is not managed properly it can lead to thermal damage such as tensile residual stresses, discoloration, softening, re-hardening, and cracks. Coherent (laminar) jets provide coolant fluid delivery for maximized lubrication at the contact zone critical to defect-free grinding at high material remove rates. Turbulent jet spread does not allow the coolant jet to effectively breach the high-speed air boundary layer - created by entrainment of air along the surface of rapidly rotating grinding wheel - and gain access to the hot wheel-to-workpiece interface. It is unknown to what degree sprayed coolant is delivered to the grinding zone. The spray particle and spray droplet size analyzer will enable improved understanding of the laminar to turbulent transition of a fluid jet under various working conditions. Numerical modeling of the disintegration and transition to turbulence of coherent coolant jets represents challenges that will be overcome using the instrument to verify numerical model of jet break-up. The ability to accurately model coolant jet coherence is a potential game changer in the field of metalworking. To validate the numerical model, the performance of manufactured nozzles will be studied experimentally using the instrument. Also, the presence of particles in the coolant causes contamination of the nozzle that affects the jet disintegration. The evaluation of jet coherence together with quantification of particles in the jet will assist in prediction of need for replacement of the nozzle. Selection of cooling jet parameters to ensure that the jet is coherent will be achieved by studying jet break-up using the acquired instrument.This project is jointly funded by the Major Instrumentation Research Program (MRI) and the Advanced Manufacturing Program (AM) in the division of Civil, Mechanical and Manufacturing Innovation (CMMI).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.