Buoyancy-Induced Heat Transfer inside Compressor Rotors: Overview of Theoretical Models
Buoyancy-Induced Heat Transfer inside Compressor Rotors: Overview of Theoretical Models
复制标题
压缩机转子内的浮力诱导传热：理论模型概述
DOI：
10.3390/aerospace5010032
复制
发表时间：
2018
影响因子：
3.2
通讯作者：
G. Lock
中科院分区：
文献类型：
--
作者：
J. Owen;Hui Tang;G. Lock
燃气涡轮压缩机中的压力增加，特别是在压力比可以高于50：1的航空发动机中，需要更小的压缩机叶片，并且越来越关注叶片间隙控制。叶片间隙取决于压缩机盘的径向增长，而径向增长又取决于盘中的温度和应力。由于圆盘空腔内的流动是浮力驱动的，圆盘温度的计算是一个共轭问题：圆盘的热传递与空腔内的空气温度耦合。腔内的流动是三维的、不稳定的、不稳定的，因此计算流体动力学不仅昂贵且耗时，而且在现代压缩机中发现的高格拉肖夫数下也无法获得精确的解。许多设计师依赖于基于不适当的物理模型的经验方程，最近作者发表了一系列关于压缩机转子内旋转空腔中浮力诱导传热的物理理论建模的论文。从这些模型，所有这些都是层流的预测，已经验证了使用开放和封闭的压缩机钻机的一系列流动参数的压缩机转子内发现的代表性的测量。(The层流浮力模型可用于较大的Grashof数（高达10
12
大多数工程师认为流动是湍流，这归因于流体核心中的大科里奥利加速度，以及核心的旋转速度与盘的旋转速度之间只有很小的差异。多达223个单独的测试进行了分析，在验证的模型，并取得了良好的一致性之间的预测和测量大多数情况下。本文将这些文献中的方程进行了汇总，希望对设计和研究工作者有所帮助。本文还指出了模型的局限性，所有这些模型都是稳定流，并表明需要进一步的实验证据。
Increasing pressures in gas-turbine compressors, particularly in aeroengines where the pressure ratios can be above 50:1, require smaller compressor blades and an increasing focus on blade-clearance control. The blade clearance depends on the radial growth of the compressor discs, which in turn depends on the temperature and stress in the discs. As the flow inside the disc cavities is buoyancy-driven, calculation of the disc temperature is a conjugate problem: the heat transfer from the disc is coupled with the air temperature inside the cavity. The flow inside the cavity is three-dimensional, unsteady and unstable, so computational fluid dynamics is not only expensive and time-consuming, it is also unable to achieve accurate solutions at the high Grashof numbers found in modern compressors. Many designers rely on empirical equations based on inappropriate physical models, and recently the authors have produced a series of papers on physically-based theoretical modelling of buoyancy-induced heat transfer in the rotating cavities found inside compressor rotors. Predictions from these models, all of which are for laminar flow, have been validated using measurements made in open and closed compressor rigs for a range of flow parameters representative of those found inside compressor rotors. (The fact that laminar buoyancy models can be used for large Grashof numbers (up to 10
12
), where most engineers expect the flow to be turbulent, is attributed to the large Coriolis accelerations in the fluid core and to the fact that there is only a small difference between the rotational speed of the core and that of the discs.) As many as 223 separate tests were analysed in the validation of the models, and good agreement between the predictions and measurements was achieved for most of these cases. This overview paper has collected together the equations from these papers, which should be helpful to designers and research workers. The paper also points out the limitations of the models, all of which are for steady flow, and shows where further experimental evidence is needed.
影响因子：
3.7
作者：
D. Pitz;O. Marxen;J. Chew
通讯作者：
D. Pitz;O. Marxen;J. Chew