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GOALI: Frictional Ignition of Metals in High-Pressure Oxygen Environments

GOALI：高压氧气环境中金属的摩擦点火

基本信息

批准号：
2004913
负责人：
Zachary Cordero
金额：
$ 49.83万
依托单位：
Massachusetts Institute of Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-15 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004913&HistoricalAwards=false
关键词：
GOALI Frictional Ignition Metals Pressure

项目摘要

Non-Technical Summary The oxidizer-rich staged combustion (ORSC) and full-flow staged combustion (FFSC) rocket engines currently under development offer dramatic improvements in fuel efficiency and thrust over the traditional gas generator engine cycle. ORSC and FFSC power cycles use a preburner to produce an oxidizer-rich stream of combustion gases that drives the turbine, then burns with the remaining fuel in the main combustion chamber. However, operating the preburner of a rocket engine under oxidizer-rich conditions presents significant materials engineering challenges; most materials are susceptible to ignition and combustion under a high-pressure oxygen-rich environment. One of the ignition mechanisms of greatest concern to rocket engines is frictional ignition due to rubbing of high-speed rotating components in high-pressure oxygen-rich environment. Two notable recent launch failures, Sea Launch’s NSS-8 and Orbital’s Orb-3, are believed to have arisen from frictional ignition of metals. This work focuses on determining the physical mechanisms that drive frictional ignition of engineering alloys in high-pressure oxygen. Experiments on high-speed sliding wear suggest that frictional ignition results from the onset of severe oxidational wear, corresponding to a breakdown of a lubricating oxide tribolayer at the rubbing interface. The underlying causes of this wear transition are poorly understood and likely vary according to the specific material system. This proposal will address this gap in understanding, revealing, for the first time, the effects of test conditions and alloy chemistry on the properties, structure, and stability of oxide tribolayers that form on several important aerospace engineering alloys. These insights will connect micro-scale structural evolution processes with macro-scale materials phenomena, such as frictional ignition, with important scientific implications for the fields of tribology, mechanochemistry, and physical metallurgy. This understanding could be used by materials scientists to design new alloys resistant to catastrophic frictional ignition, and by rocket engine designers to implement design and manufacturing modifications that reduce the risk of engine failure due to unintended ignition of metal engine components. These developments will enable robust reusable launch vehicles that will serve as the foundation for key emerging space technologies, such as satellite mega-constellations for high-speed space-based internet, reliable interplanetary crew and commerce transport, and large in-space RF telescopes for low-frequency radio astronomy, all of which promise to transform commerce and our understanding of the universe.Technical SummaryPredicting the conditions under which oxide tribolayers break down during high-speed sliding wear remains a significant challenge because the underlying mechanisms that control the growth, properties, and thermomechanical stability of tribolayers are poorly understood. This is partly because oxide tribolayers appear to grow via an iterative transient oxidation process, which complicates direct comparison with oxide scales formed during conventional static oxidation. Using a combination of wear experiments, contact mechanics theory, and metallurgical thermochemistry, this proposed research will test the hypothesized relationship between the onset of severe oxidational wear and frictional ignition, as well as reveal the mechanisms of oxide breakdown during high-speed sliding. The project will begin with high-speed wear testing experiments to characterize the friction, wear, and ignition behaviors of several important model materials under high-pressure oxygen environments. Next, the wear surface and mechanical properties of recovered samples will be characterized ex situ to gain insight into the micro-scale mechanisms that drive oxide breakdown. Finally, the experimental results will be combined with physics-based models of frictional heating, oxide growth, and contact mechanics in order to determine the relationship between oxide breakdown and frictional ignition. The results of this work will reveal an important relationship between tribolayer breakdown and frictional ignition in mission-critical aerospace alloys, as well as the physical mechanisms that drive oxide tribolayer growth and degradation at the onset of severe oxidational wear.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.

目前正在开发的富氧化剂分级燃烧（ORSC）和全流分级燃烧（FFSC）火箭发动机在燃油效率和推力方面都比传统的燃气发生器发动机有了显著的提高。ORSC和FFSC动力循环使用预燃烧器产生一种富含氧化剂的燃烧气体流，驱动涡轮机，然后在主燃烧室燃烧剩余的燃料。然而，在富含氧化剂的条件下运行火箭发动机的预燃器提出了重大的材料工程挑战；大多数材料在高压富氧环境下容易着火和燃烧。高压富氧环境下高速旋转部件的摩擦点火是火箭发动机最为关注的点火机理之一。最近两次引人注目的发射失败，海上发射公司的NSS-8和轨道轨道公司的Orb-3，被认为是由金属摩擦点火引起的。这项工作的重点是确定在高压氧气中驱动工程合金摩擦点火的物理机制。高速滑动磨损实验表明，摩擦点火是由严重氧化磨损的开始引起的，对应于摩擦界面的润滑氧化物摩擦层的破裂。这种磨损转变的根本原因尚不清楚，并且可能根据特定的材料系统而变化。该提案将解决这一理解上的差距，首次揭示测试条件和合金化学对几种重要航空航天工程合金上形成的氧化物摩擦层的性能、结构和稳定性的影响。这些见解将把微观尺度的结构演变过程与宏观尺度的材料现象（如摩擦点火）联系起来，对摩擦学、机械化学和物理冶金领域具有重要的科学意义。材料科学家可以利用这种理解来设计抗灾难性摩擦点火的新合金，火箭发动机设计师也可以利用这种理解来实施设计和制造修改，以降低由于金属发动机部件意外点火而导致发动机故障的风险。这些发展将使强大的可重复使用的运载火箭成为关键新兴空间技术的基础，例如用于高速天基互联网的卫星巨型星座，可靠的星际船员和商业运输，以及用于低频射电天文学的大型太空RF望远镜，所有这些都有望改变商业和我们对宇宙的理解。预测氧化摩擦层在高速滑动磨损过程中分解的条件仍然是一个重大挑战，因为控制摩擦层生长、性能和热机械稳定性的潜在机制尚不清楚。这部分是因为氧化摩擦层似乎是通过迭代的瞬态氧化过程生长的，这使得与传统静态氧化过程中形成的氧化层的直接比较变得复杂。结合磨损实验、接触力学理论和冶金热化学，本研究将验证严重氧化磨损的发生与摩擦点火之间的假设关系，并揭示高速滑动过程中氧化物击穿的机制。该项目将从高速磨损测试实验开始，以表征几种重要模型材料在高压氧气环境下的摩擦、磨损和点火行为。接下来，将对回收样品的磨损表面和机械性能进行非原位表征，以深入了解驱动氧化物分解的微观机制。最后，实验结果将与摩擦加热、氧化物生长和接触力学的物理模型相结合，以确定氧化物击穿与摩擦点火之间的关系。这项工作的结果将揭示关键任务航空航天合金中摩擦层击穿与摩擦点火之间的重要关系，以及在严重氧化磨损开始时驱动氧化摩擦层生长和降解的物理机制。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。