Issues in performance measurement of CO2 compressor near the critical point

Lee, Jekyoung; Baik, Seungjoon; Cho, Seong Kuk; Eun, Jae; Lee, Jeong Ik

doi:10.1016/j.applthermaleng.2015.10.063

Cited by 40 publications

(11 citation statements)

References 6 publications

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“…They believed performance measurement uncertainty issues in a low pressure ratio compressor should be appreciated. 43,44 The same issues have also been discussed by Pham et al 45 Sandia National Laboratories provided an overview of corrosion mechanisms in SCO 2 , as well as in molten salts for nuclear applications. 46 They found that the uncertainty in the longterm reliability of various components has become more visible, when more hours of operation applied to the Recompression Closed Loop Brayton Cycle power loop.…”

Section: Other Research Progressmentioning

confidence: 81%

“…Moreover, according to the process of the data post-processing, Lee et al. 43,44 found out that the SCO 2 compressor performance experiment has an issue of uncertainty on the performance measurement. They believed performance measurement uncertainty issues in a low pressure ratio compressor should be appreciated.…”

Section: Issues For the Application Of Sco2 In Nuclear Engineeringmentioning

confidence: 99%

See 1 more Smart Citation

The application of supercritical CO₂ in nuclear engineering: A review

Gui

Yang

et al. 2018

The Journal of Computational Multiphase Flows

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Due to its advantages of low critical pressure and temperature, stability, non-toxic, abundant reserves and low cost, supercritical CO 2 becomes one of the most common supercritical fluids in modern researches and industries. This paper presents an overview focusing on the researches of supercritical CO 2 in nuclear engineering and prospects its applications in the field of nuclear industry. This review includes the recent progresses of supercritical CO 2 research as: (1) energy conversion material in both recompression cycle and Brayton cycle and its applicability in Generation IV reactors; (2) reactor core coolant in the Echogen power system and reactors at MIT, Kaist and Japan, and other applications, e.g. hydrogen production. Based on the rapid progress of research, the supercritical CO 2 is considered to be the most promising material in nuclear industries.

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Section: Other Research Progressmentioning

confidence: 81%

Section: Issues For the Application Of Sco2 In Nuclear Engineeringmentioning

confidence: 99%

The application of supercritical CO₂ in nuclear engineering: A review

Gui

Yang

et al. 2018

The Journal of Computational Multiphase Flows

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“…However, the aerothermodynamic properties of CO 2 near the critical point show severe nonlinear behaviors which significantly deviate from the perfect gas. The sharp variation of the fluid properties means larger uncertainty in experimental measurements and lower accuracy in numerical simulations for centrifugal compressors [9,10]. In recent years, a significant effort has been made to improve the reliability of numerical simulations for compressors running near the critical point.…”

Section: Introductionmentioning

confidence: 99%

A New Method for Impeller Inlet Design of Supercritical CO2 Centrifugal Compressors in Brayton Cycles

Zhao

Yao

et al. 2020

Energies

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Supercritical Carbon Dioxide (SCO2) is considered as a potential working fluid in next generation power and energy systems. The SCO2 Brayton cycle is advantaged with higher cycle efficiency, smaller compression work, and more compact layout, as compared with traditional cycles. When the inlet total condition of the compressor approaches the critical point of the working fluid, the cycle efficiency is further enhanced. However, the flow acceleration near the impeller inducer causes the fluid to enter two-phase region, which may lead to additional aerodynamic losses and flow instability. In this study, a new impeller inlet design method is proposed to achieve a better balance among the cycle efficiency, compressor compactness, and inducer condensation. This approach couples a concept of the maximum swallowing capacity of real gas and a new principle for condensation design. Firstly, the mass flow function of real gas centrifugal compressors is analytically expressed by non-dimensional parameters. An optimal inlet flow angle is derived to achieve the maximum swallowing capacity under a certain inlet relative Mach number, which leads to the minimum energy loss and a more compact geometry for the compressor. Secondly, a new condensation design principle is developed by proposing a novel concept of the two-zone inlet total condition for SCO2 compressors. In this new principle, the acceptable acceleration margin (AAM) is derived as a criterion to limit the impeller inlet condensation. The present inlet design method is validated in the design and simulation of a low-flow-coefficient compressor stage based on the real gas model. The mechanisms of flow accelerations in the impeller inducer, which form low-pressure regions and further produce condensation, are analyzed and clarified under different operating conditions. It is found that the proposed method is efficient to limit the condensation in the impeller inducer, keep the compactness of the compressor, and maintain a high cycle efficiency.

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“…Various institutions have tried to manufacture and test S-CO 2 compressors in their facilities by collaborating with turbomachinery vendors. Sandia National Laboratory and Barber-Nichols Inc. in the U.S. and KAIST, Korea Atomic Energy Research Institute and Jinsol Turbo Machinery in Korea are examples of such collaboration [7][8][9]. However, these experimental studies have mostly focused on applying existing accumulated air compressor technologies to the S-CO 2 compressor since an S-CO 2 Brayton cycle is not yet mature power generation technology.…”

Section: Introductionmentioning

confidence: 99%

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

et al. 2019

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To overcome the degradation of the cycle efficiency of a supercritical carbon dioxide (S-CO2) Brayton cycle with dry cooling, this study proposes an improved design of an S-CO2 centrifugal compressor. The conventional air centrifugal compressor can achieve higher efficiency as backsweep angle increases. However, the structural issue restricts the maximum allowable angle (−50~−56°). In this study, an S-CO2 centrifugal compressor performance was examined while changing the backward sweep angle at impeller exit to study if the previous optimum backsweep angle for an air centrifugal compressor is still valid when the fluid has changed. It is shown through an analysis that an S-CO2 centrifugal compressor can achieve the highest efficiency at −70° backsweep angle, which is greater than the typical design value. The S-CO2 centrifugal compressor is less restricted from a structural integrity issue because it has low relative Mach number regardless of the low sound speed near critical point (Tc = 304.11 K, Pc = 7377 kPa). It is also shown in the paper that the variation of compressibility factor does not impact on its total to total efficiency since its Mach number is still lower than unity. Finally, it is also shown that a backward sweep impeller can achieve higher pressure ratio and operate stably in wider range as the mass flow rate is decreased. As further works, the suggested concept will be validated by the structural analysis and the compressor performance test.

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Issues in performance measurement of CO2 compressor near the critical point

Cited by 40 publications

References 6 publications

The application of supercritical CO₂ in nuclear engineering: A review

The application of supercritical CO₂ in nuclear engineering: A review

A New Method for Impeller Inlet Design of Supercritical CO2 Centrifugal Compressors in Brayton Cycles

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

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Issues in performance measurement of CO2 compressor near the critical point

Cited by 40 publications

References 6 publications

The application of supercritical CO2 in nuclear engineering: A review

The application of supercritical CO2 in nuclear engineering: A review

A New Method for Impeller Inlet Design of Supercritical CO2 Centrifugal Compressors in Brayton Cycles

Direction for High-Performance Supercritical CO2 Centrifugal Compressor Design for Dry Cooled Supercritical CO2 Brayton Cycle

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The application of supercritical CO₂ in nuclear engineering: A review

The application of supercritical CO₂ in nuclear engineering: A review