Aerodynamic Improvement of Centrifugal Compressors

航空发动机技术的进一步改进对于航空运输业应对不可避免的燃油价格上涨、竞争和环境压力至关重要。离心压气机的每级压比远高于目前大多数飞机发动机中使用的轴向压气机，可以在这一改进中发挥主要作用。事实上，用一个离心压气机级取代许多轴向压气机级将导致更简单、更短和更轻的航空发动机。但是，离心式压气机的气动性能和工艺必须接近轴流压气机。该研究将以轴向压缩机技术的经验和发展为基础，显著改善离心压缩机的空气动力学，使其在航空推进领域得到更广泛的应用。它将寻求提高离心式压缩机的绝热效率和失速裕度，并减少这些参数随发动机年龄的退化。我们建议通过对流动物理的研究和理解，并利用增材制造（3D打印）技术的快速发展，采用一种开创性的经济有效的方法，开发有效的设计和流动控制策略，从而实现这一目标。***首先，增材制造技术允许探索高度复杂的设计，这些设计是标准制造技术不实用或不可能实现的。此外，聚合物3D打印技术允许快速制造相对便宜的测试平台。这项研究将依赖于低成本的全仪器旋转离心压缩机钻机，这些钻机是由大四本科生组成的大型团队在最后一年的两个学期的设计项目课程中使用3D打印定制设计和制造的，该项目已经成功生产了三年的压缩机钻机。从第一台新钻机获得的测试数据将用于验证计算流体动力学（CFD）模拟工具，以捕获离心式压缩机中的复杂流场。研究生将使用该仿真工具和分析建模来阐明/理解与所研究的三个方面相关的流动机制，并预测气动改进策略的效果。第二台新钻机将用于实验验证这些策略。在此过程中，这项研究将为大量HQP在工程（分析/数值/实验）的所有三个方面提供具有成本效益的培训，并为工业界提供广受欢迎的离心式压缩机技术专家，不仅适用于航空，而且适用于使用该技术的各种行业

A step improvement in aero-engine technology will be crucial for the air transport industry to confront the inevitable increase in fuel prices, competition and environmental pressures. The centrifugal compressor, which has far superior pressure ratio per stage than axial compressors currently used in most aircraft engines, can play a major role in this improvement. Indeed, the replacement of many axial compressor stages by a single centrifugal compressor stage will result in simpler, shorter and lighter aero-engines. However, the aerodynamic performance and technology of centrifugal compressors must be brought close to that of axial compressors. The proposed research will build on experience and developments in axial compressor technology to significantly improve the aerodynamics of centrifugal compressors for wider use in aero-propulsion. It will seek to improve the adiabatic efficiency and stall margin of centrifugal compressors as well as reduce the degradation of these parameters with engine age. It is proposed to do so through investigation and understanding of the flow physics and developing effective design and flow control strategies by using a pioneering cost-effective approach that takes advantage of the rapid evolution in additive manufacturing (3D printing) technology. *** First, additive manufacturing technology allows for the exploration highly complex designs that were not practical or possible with standard manufacturing technology. In addition, polymer 3D printing technology allows for fast fabrication of relatively inexpensive test rigs. The proposed research will rely on low-cost fully instrumented rotating centrifugal compressor rigs custom designed and built with 3D printing by large teams of senior undergraduate students in a two-semester final-year design project course that has successfully produced compressor rigs for three years. The test data obtained from the first new rig will serve to validate a computation fluid dynamics (CFD) simulation tool to capture the complex flow field in centrifugal compressors. This simulation tool will be used, along with analytical modelling, by graduate students to elucidate/understand the flow mechanisms associated with the three aspects studied and predict the effect of aerodynamic improvement strategies. The second new rig will then serve to experimentally validate these strategies. In doing so, this research will provide cost-effective training of a large number of HQP in all three aspects of engineering (analytical/numerical/experimental) and provide industry with sought-after experts in centrifugal compressor technology not only for aeronautics but also for the very wide variety of industries that use this technology.**