Flow mechanism and back gap windage loss of a sCO2 radial inflow turbine with impeller scallops

IF 3.4 3区工程技术 Q2 CHEMISTRY, PHYSICAL Journal of Supercritical Fluids Pub Date : 2024-11-08 DOI:10.1016/j.supflu.2024.106453

Zhuobin Zhao , Jianxin Liao , Qinghua Deng , Jun Li , Zhenping Feng

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Abstract

The Internal flow mechanisms and windage loss in impeller back gap of a supercritical carbon dioxide (sCO₂) radial inflow turbine with scallops are comprehensively investigated in this paper. The study emphasizes the effects of scallop depth and leakage outlet pressure. The results indicate that scallop structures lead to a degradation in overall turbine performance. Under design conditions, a turbine with a scallop depth ratio of 0.5 exhibits a 3.7 % reduction in efficiency and a 3.4 % decrease in total power compared to no scallop configuration. Furthermore, as scallop depth increases, the skin friction coefficient decreases in the disk gap while it increases for the seal in the impeller back gap. Increasing leakage outlet pressure reduces the leakage flow rate and skin friction coefficient. Fitted models for skin friction coefficient are proposed respectively. The conclusions providing valuable insights for designing and optimizing sCO₂ radial inflow turbines with scallops.

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带扇贝叶轮的 sCO2 径向流入涡轮机的流动机制和背隙风蚀损失

本文全面研究了带扇贝的超临界二氧化碳（sCO2）径流式水轮机叶轮背隙的内部流动机制和风蚀损失。研究强调了扇贝深度和泄漏出口压力的影响。结果表明，扇贝结构会导致涡轮机整体性能下降。在设计条件下，与无扇贝结构相比，扇贝深度比为 0.5 的涡轮机效率降低了 3.7%，总功率降低了 3.4%。此外，随着扇贝深度的增加，圆盘间隙的表皮摩擦系数降低，而叶轮后间隙密封的表皮摩擦系数增加。增加泄漏出口压力会降低泄漏流速和表皮摩擦系数。分别提出了表皮摩擦系数的拟合模型。结论为设计和优化带扇贝的 sCO2 径向流入水轮机提供了有价值的见解。

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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.