US-Egypt Cooperative Research: Experimental Investigation and Control of an Integrated JB/AMB rotor bearing

该项目支持詹姆斯麦迪逊大学的Eric Maslen博士与埃及开罗大学的Aly El-Shafei博士的合作研究工作。他们计划研究“集成JB/AMB的设计和控制开发”。大多数大型汽轮机使用流体膜轴颈轴承（JB）来支撑转子，限制振动，并控制潜在的不稳定性。最近，一种替代的轴承技术已经进入商业用途：主动磁轴承（AMB）。这些轴承提供了许多优点，特别是因为它们可以提供非常有利的动态特性，有助于管理转子稳定性。该项目的目标是将滑动轴承的上级承载能力与主动磁轴承的可控性特征相结合，主动磁轴承可以抵消与流体膜滑动轴承相关的不稳定性。为了利用两种轴承设计的优势，PI将探索将两种轴承组合成一个单一的集成轴承设计。该研究的核心假设是，可以物理地共同定位流体膜和磁轴承，并构造控制器，以a）确保转子/轴承系统在所有感兴趣的速度下的稳定性，B）满足使两个轴承机构之间的竞争最小化的负载分配目标，c）最小化方位的加权组合-这是为了减小传递的力和转子振动，以显著减小给定水平的转子不平衡的转子振动或基座力传递。研究将开发混合轴承的概念，将流体膜和磁性轴承集成到单个部件中。这种方法的一个优点是，两个装置可以以互补的方式操作，其中流体膜部件提供大部分负载能力和容错能力，而磁性部件增强稳定性。预计这种组合可以提供比目前可倾瓦液膜轴承更高的稳定裕度。这种方法的第二个优点是，混合轴承可以允许针对特定应用的性能优化，因为它较少依赖于硬件来控制其操作。通过选择算法结合轴承控制，混合轴承设计可以适应系统变化或升级，以延长轴承的使用寿命。还可以提供一组用于解决共同系统动态的常规控制器和允许原位可调谐性的选项。该结果对于大型固定转子系统（例如，燃气轮机、涡轮膨胀机、兆瓦级电动机）。通过在美国和埃及的研究人员之间建立强有力的合作，该项目将促进科学和工程思想的交流以及文化交流。美国和埃及的团队都包括初级科学家，他们将在两个方向进行多次旅行。美国的活动将在詹姆斯麦迪逊大学进行，这是一所主要的本科院校，将整合工程学院和综合科学技术系的本科生。此外，本研究的结果将提供教育效益的两个工程课程作为一个案例研究提供了一个例子的设计和分析。第三，随着高速旋转机械普及到现代社会的技术基础，这项研究将可能对广大公众的福利产生直接影响。这项研究对提高这类机械的效率，特别是在能源部门具有重要的潜力。轴承技术的进步将提高相关技术部门的整体性能和生存能力，从而为社会带来好处。该项目由美国-埃及联合科学和技术基金项目资助。这些合作项目的美方支持由美国国务院提供给国家科学基金会。埃及政府为合作的埃及方面提供支持。

This project supports a cooperative research effort by Dr. Eric Maslen of James Madison University with Dr. Aly El-Shafei of Cairo University in Cairo, Egypt. They plan to study "The Design and Control Development of an Integrated JB/AMB". Most large turbomachinery use fluid film journal bearings (JBs) to support the rotor, limit vibrations, and to control potential instabilities. More recently, an alternate bearing technology has come into commercial use: active magnetic bearings (AMBs). These bearings offer a number of advantages, particularly because they can provide very favorable dynamic properties, useful in managing rotor stability. The goal of the project is to integrate the superior load capacity of journal bearings with the controllability characteristics of active magnetic bearings which can counteract the instability associated with fluid film journal bearings.To capitalize on the advantages of both bearing designs, the PIs will explore the combination of both bearings into a single integrated bearing design. The core hypothesis of the research is that it is possible to physically co-locate a fluid film and a magnetic bearing and construct a controller to a) ensure stability of the rotor/bearing system at all speeds of interest, b) satisfy a loadsharing objective that minimizes competition between the two bearing mechanisms, c) minimize a weighted combination of bearing-transmitted forces and rotor vibration to significantly reduce rotor vibration or pedestal force transmission for a given level of rotor unbalance.This research will develop the concept of a hybrid bearing,integrating a fluid film and magnetic bearing into a single component. One merit of this approach is that the two devices can operate in a complementary fashion with the fluid film component providing the bulk of load capacity and fault tolerance, while the magnetic component enhances the stability. It is expected that the combination can offer substantially higher stability margins than are currently afforded by tilt-pad fluid film bearings. The second merit of this approach is that a hybrid bearing can allow for performance optimization to a particular application as it is less dependent on hardware to control its operation. By incorporating bearing control through a choice of algorithms, the hybrid bearing design can adapt with system changes or upgrades to prolong the useful life of the bearing. A set of conventional controllers for addressing common system dynamics and an option for allowing in-situ tunability could also be provided. The results could have an immediate benefit for large stationary rotor systems (e.g., gas turbines, turbo expanders, megawatt scale motors). By building a strong collaboration between researchers in the United States and in Egypt, the project will promote exchange of scientific and engineering ideas as well as cultural exchange. Both the US and the Egyptian teams include junior scientists who will make multiple trips in both directions. The US activity will be conducted at James Madison University, a primarily undergraduate institution and will integrate undergraduate students from both the School of Engineering and from the Department of Integrated Science and Technology. Further, the results of this research will provide educational benefit for two engineering courses as a case study providing an example of design and analysis. Third, the research will potentially have direct impact on the welfare of the public at large, as high-speed rotating machinery pervades the technical base of modern societies. This resarch has significant potential to improve the efficiency of such machinery, especially in the energy sector. Advances in bearing technology will improve the overall performance and viability of the dependent technology sectors, which in turn provides benefits to the societies. This project is funded through the US-Egypt Joint Science and Technology Fund program. Support for the U.S. side of these cooperative projects is provided to the National Science Foundation by the U.S. Department of State. The Egyptian Government provides support for the Egyptian side of the collaboration.