RUI/Collaborative Research: Investigation of Ion Currents in the Oxyfuel Cutting Flame and their Links to Critical Process Parameters

该合同旨在解决持续存在的严峻挑战，提供过程反馈，以更好地控制和完全自动化氧燃料切割过程。虽然它已经有一个多世纪的历史了，但氧燃料（或“火焰切割”）在厚钢上无与伦比的性能使它成为造船厂、建筑、铁路、国防和无数其他重工业的永恒宠儿。恶劣的操作环境（明火，极端高温）限制了现代传感器套件提供可靠数据的能力，这些数据对于过程反馈控制和自动化至关重要。初步测量表明，与火焰本身相关的称为“离子流”的电子事件可以可靠地指示重要的过程状态，从而激发了这个问题的潜在解决方案。这项研究将通过建模和实验来探索火焰的潜在物理特性。如果成功，这项工作可以实现可靠的、经济有效的控制和自动化的含氧燃料切割过程，这是美国许多核心行业非常感兴趣的能力，包括建筑、国防和能源应用的主要设备制造。这是一项合作研究，实验工作将在以本科生为主的学院进行，而大部分建模工作将在合作大学进行。让本科生参与与工业相关的研究项目，有望鼓励和促进先进制造业的发展，并鼓励更广泛的参与。与合作大学和工业合作伙伴IHT-Automation的合作也将提高参与该项目的研究生和本科生的劳动力准备。这项工作测试了一个低阶离子传输模型的有效性，该模型考虑了与氧燃料切割炬和工件之间产生的电流-电压特性相关的距离、工作表面/切口化学活性和火焰化学活性。一种新的旋转圆盘朗缪尔探针技术将建立火焰中离子密度的空间分辨图。以这些数据为参考，将在最近开发的简化化学动力学模型上建立多维计算流体动力学模拟，以全面解决整个流动中带电物质的形成和输运。对模型和实验结果的后续分析将验证或拒绝一个高度简化的一维传输模型，该模型将火焰的电流-电压特性与关键事件联系起来。其中包括僵局漂移、准备穿孔、穿孔成功/失败、切割损失预测、燃料/氧气比漂移、熄火等等。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。

The award seeks to address serious persistent challenges in providing process feedback to better control and fully automate the oxyfuel cutting process. Though it is more than a century old, oxyfuel's (or 'flame-cutting's') unparalleled performance on thick steel has rendered it an enduring favorite in shipyards, building construction, rail, defense, and countless other heavy industries. The harsh operating environment (open flames, extreme heat) limit the ability of contemporary sensor suites to provide reliable data essential for process feedback control and automation. A potential solution to this problem is motivated by preliminary measurements demonstrating that electrical events called 'ion currents' associated with the flame itself can reliably indicate vital process states. The research will probe the underlying physics of the flame via modeling and experimental efforts. If successful the work could realize reliable cost-effective control and automation of the oxyfuel cutting process, a capability of great interest to many core US industries involved in construction, and major equipment manufacture for defense and energy applications. This is a collaborative research, whereby the experimental work will be undertaken at a predominantly undergraduate institute, while most of the modeling efforts will be conducted at the partner university. Engaging undergraduate students in industrially relevant research projects will hopefully encourage and promote advanced manufacturing beyond those immediately involved, and encourage broader participation. Collaboration with the partner university and the industrial partner, IHT-Automation, will also increase the workforce preparedness of both the graduate student and undergraduate students working on this project. This work tests the validity of a reduced-order ion transport model that considers standoff distance, work-surface/kerf chemical activity, and flame chemical activity with respect to the resulting current-voltage characteristic between the oxyfuel cutting torch and the workpiece. A novel spinning disc Langmuir probe technique will establish a spatially resolved map for the ion densities in the flame. Using these data as a reference, a multi-dimensional computational fluid dynamics simulation will be built on recently developed reduced chemical kinetic models to fully resolve the formation and transport of charged species throughout the flow. Subsequent analysis of the modeling and experimental results will validate or reject a highly simplified one-dimensional transport model relating the current-voltage characteristic of the flame to critical events. These include drift in standoff, ready-to-pierce, pierce success/failure, loss-of-cut prediction, drift in fuel/oxygen ratio, flameout, and potentially others.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.