Buoyancy-Induced Flow and Heat Transfer inside Compressor Rotors

燃气涡轮机代表了现代工程中最先进的例子之一。全球每天有超过100，000个定期航班，人们越来越依赖喷气发动机来满足我们的运输需求。不断增加的燃料成本和苛刻的环境立法促使喷气发动机制造商生产越来越高效的动力装置，以保持竞争力。欧洲航空航天研究咨询理事会（ACARE）制定了到2020年将发动机燃料消耗和二氧化碳（CO2）排放量相对于2000年水平减少20%的目标。为了提高燃气轮机的功率输出和效率，从而降低燃料消耗和CO2排放量，有必要提高压缩机的压力比。这给航空发动机设计者提出了一个挑战：压比越高，压气机叶片越小，叶片与机匣之间的间隙大小对压气机性能和稳定性的影响也越来越大。为了计算（和控制）瞬态和稳态条件下的这些小间隙，有必要确定压气机盘的径向增长。这又需要计算盘的瞬态温度，这涉及计算浮力引起的旋转流和压缩机转子内部的热传递。这些流动是三维的、不稳定的、不稳定的，即使用现在最大的计算机计算也是极其困难和昂贵的。这对发动机设计人员提出了一个具有挑战性的问题，研究涉及一个综合的理论，计算和实验方案来解决这个问题。该项目旨在将联合收割机实验、计算和理论相结合，以产生对浮力诱导的旋转流的基本理解，并开发用于燃气轮机压缩机间隙控制技术的CFD代码和理论模型。该提案代表了英国两个领先的研究机构在这一领域之间令人兴奋的新合作，这两个研究机构都具有为行业带来影响的良好记录。巴斯和萨里研究团队的互补经验和专业知识非常适合这样一个合作企业，而劳斯莱斯的建议和支持对其成功至关重要。这项研究不仅旨在了解这些复杂的旋转流，还将导致下一代航空发动机设计师使用的CFD代码和理论模型的开发。

The gas turbine represents one of the most highly advanced examples of modern day engineering. With over 100,000 scheduled flights per day globally, there is an ever increasing reliance on jet engines to meet our transportation demands. Increasing fuel costs and demanding environmental legislation have driven jet engine manufacturers to produce increasingly efficient power-plants in order to remain competitive. The Advisory Council for Aerospace Research in Europe (ACARE) have set out the target of a 20% reduction in engine fuel consumption and carbon dioxide (CO2) emissions by 2020, relative to 2000 levels.To increase the power output and efficiency - and consequently to reduce the fuel consumption and CO2 production - of gas turbines, it is necessary to increase the pressure ratio of the compressors. This presents a challenge for designers of aeroengines: the higher the pressure ratio, the smaller the compressor blades become, and the size of the clearance between the blades and casing has an increasing effect on the compressor performance and stability. To calculate (and control) these small clearances for transient and steady conditions, it is necessary to determine the radial growth of the compressor discs. This in turn requires the calculation of the transient temperatures of the discs, which involves the calculation of the buoyancy-induced rotating flow and heat transfer inside the compressor rotors. These flows - which are three-dimensional, unsteady and unstable - are extremely difficult and expensive to compute, even by the biggest computers now available. This presents a challenging problem for engine designers, and the research involves an integrated theoretical, computational and experimental programme to address this problem. This project aims to combine experiment, computation and theory to generate a fundamental understanding of buoyancy-induced rotating flow and to develop CFD codes and a theoretical model for use in the compressor-clearance-control technology of gas turbines. The proposal represents an exciting new collaboration between two of the UK's leading research institutes in this area, both with a proven track record of delivering impact to industry. The complementary experience and expertise of the research teams at Bath and Surrey are perfectly suited for such a collaborative enterprise, and the advice and support from Rolls Royce is vital for its success. Not only would this research seek to understand these complex rotating flows, it would also lead to the development of CFD codes and theoretical models that would be used by the designers of the next generation of aeroengines.