Aerodynamic Improvement of Centrifugal Compressors

航空发动机技术的进步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。离心式压气机的每级压比远远高于目前大多数飞机发动机中使用的轴流压气机，它可以在这一改进中发挥重要作用。事实上，用一个离心式压气机级取代多个轴流压气机级将使航空发动机更简单、更短、更轻。然而，离心式压缩机的气动性能和技术必须接近轴流压缩机。拟议的研究将建立在轴流压缩机技术的经验和发展的基础上，以显著改善离心式压缩机的空气动力学，以便在航空推进中得到更广泛的应用。它将寻求提高离心式压气机的绝热效率和失速裕度，并减少这些参数随发动机寿命的退化。建议通过调查和了解流动物理，并通过利用添加剂制造(3D打印)技术的快速发展的开创性成本效益方法来开发有效的设计和流动控制策略来实现这一点。*首先，加法制造技术允许探索使用标准制造技术不实用或不可能的高度复杂的设计。此外，聚合物3D打印技术允许快速制造相对便宜的测试台。拟议的研究将依赖于由大四本科生组成的大型团队通过3D打印定制设计和制造的低成本全仪表化旋转离心式压缩机钻机，该课程为期两学期，已成功生产了三年的压气机钻机。从第一个新试验台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。研究生将使用该模拟工具和分析模型来阐明/理解与所研究的三个方面相关的流动机制，并预测空气动力改进策略的效果。然后，第二个新钻机将用于从实验上验证这些策略。通过这样做，这项研究将在工程(分析/数值/实验)的所有三个方面为大量HQP提供具有成本效益的培训，并为行业提供广受欢迎的离心式压缩机技术专家，不仅适用于航空业，也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.**