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

该重大研究仪器(MRI)奖支持收购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。制造过程中的研磨操作会产生大量热量，这可能会对正在制造的部件造成损害。冷却液必须输送到磨削表面，但这种冷却液很容易与空气混合，导致效率较低。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喷射破碎的测量结果，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，以及冷却剂特性。冷却的改进将减少环境中的热污染，这在研磨行业中是相当重要的。该仪器还将能够评估和减少油基冷却剂的扩散和油雾的形成，这些油雾在吸入时会造成火灾危险和安全危险。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，该地区拥有俄亥俄州30%以上的制造业工人。将从该仪器中受益的学生，包括那些来自工程学中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学的基础知识，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、重新硬化和裂纹。相干(层流)射流提供冷却液输送，在接触区实现最大程度的润滑，这对高材料去除率下的无缺陷磨削至关重要。湍急的射流扩散不会使冷却剂射流有效地突破高速空气边界层--这是由于空气沿快速旋转的砂轮表面卷吸而形成的--并无法进入热砂轮与工件的界面。目前尚不清楚喷洒的冷却剂在多大程度上输送到研磨区。喷雾颗粒和喷雾液滴尺寸分析仪将有助于更好地了解流体射流在各种工作条件下从层流到湍流的转变。对凝聚冷却剂射流的解体和向湍流的转变进行数值模拟是一项挑战，将使用该仪器来验证射流破碎的数值模型。在金属加工领域，准确模拟冷却剂喷射相干性的能力是潜在的游戏规则改变者。为了验证数值模型，将利用该仪器对所制造的喷管的性能进行实验研究。此外，冷却剂中颗粒的存在会造成喷嘴的污染，从而影响射流的解体。对喷口连贯性的评价以及对喷口中颗粒的量化将有助于预测更换喷嘴的需要。选择冷却喷射参数以确保喷射连贯将通过使用所获得的仪器研究喷射分解来实现。该项目由民用、机械和制造创新(CMMI)分部的主要仪器研究计划(MRI)和先进制造计划(AM)联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.