Model of skin friction coefficient in a supercritical CO2 turbine-alternator-compressor unit

IF 3.4 3区工程技术 Q2 CHEMISTRY, PHYSICAL

Journal of Supercritical Fluids Pub Date : 2023-10-01 DOI:10.1016/j.supflu.2023.106027

Lehao Hu , Qinghua Deng , Zhouyang Liu , Jun Li , Zhenping Feng

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Abstract

To accurately predict shaft-type and disk-type windage losses in gaps of supercritical CO₂ (sCO₂) turbine-alternator-compressor (TAC) units, the factors influencing skin friction coefficients C_f,s and C_f,d are investigated, the flow characteristics are analyzed, and the models of C_f,s and C_f,d are proposed. The results reveal the C_f,s and C_f,d decrease with Reynolds number Re increasing, but rise as pressure ratio π and radius ratio η. The leakage flow rate remains constant for Re < 10⁵ and decreases when Re ≥ 10⁵ as Re increases, but grows with π and η. Furthermore, the influences of Re on flow are minor compared to π, and vorticity growth with η increases flow instability, which makes corresponding C_f,s and C_f,d grow. The maximal relative deviations of 5.24% and 4.87% prove the proposed models are reliable. These conclusions accurately predict windage loss in whole gaps of TAC units, which helps design small sCO₂ power devices.

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超临界CO2汽轮-交流-压缩机组摩擦系数模型

为了准确预测超临界CO2（sCO2）涡轮-交流发电机-压缩机（TAC）机组间隙中的轴型和盘型风损，研究了影响表面摩擦系数Cf，s和Cf，d的因素，分析了流动特性，并提出了Cf，s和Cf、d的模型。结果表明，Cf，s和Cf，d随雷诺数Re的增加而减小，但随压力比π和半径比η的增加而增大。对于Re<；当Re≥105时，随Re的增大而减小，但随π和η的增大而增大。此外，与π相比，Re对流动的影响较小，η的涡度增长增加了流动的不稳定性，使相应的Cf，s和Cf，d增长。5.24%和4.87%的最大相对偏差证明了所提出的模型是可靠的。这些结论准确预测了TAC机组整个间隙的风损，有助于设计小型sCO2功率器件。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Supercritical Fluids 工程技术-工程：化工

CiteScore

7.60

自引率

10.30%

发文量

236

审稿时长

56 days

期刊介绍： The Journal of Supercritical Fluids is an international journal devoted to the fundamental and applied aspects of supercritical fluids and processes. Its aim is to provide a focused platform for academic and industrial researchers to report their findings and to have ready access to the advances in this rapidly growing field. Its coverage is multidisciplinary and includes both basic and applied topics. Thermodynamics and phase equilibria, reaction kinetics and rate processes, thermal and transport properties, and all topics related to processing such as separations (extraction, fractionation, purification, chromatography) nucleation and impregnation are within the scope. Accounts of specific engineering applications such as those encountered in food, fuel, natural products, minerals, pharmaceuticals and polymer industries are included. Topics related to high pressure equipment design, analytical techniques, sensors, and process control methodologies are also within the scope of the journal.