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In this paper, based on the thermo dynamic design of the supercritical carbon dioxide (sCO2) centrifugal compressor, the design idea of the flow passage geometries and the method to improve the performance of the sCO2 centrifugal compressor are discussed. With the help ofcommercial software ANSYS CFX, the influence of the shape of the leading edge and trailing edge is studied, and the elliptical leading edge makes the pressure ratio 10.30% higher and the efficiency 3.95% higher than the square leading edge. By changing the forward-swept angle and backward-swept angle of the leading edge, the effects of aerodynamic swept shape in sCO2 centrifugal compressor are discussed. The effect of the gap between the impeller blade and diffuser blade is discussed, and the 10 mm gap makes the performance best. The pressure ratio is increased by 2.5% compared with the original design, while at the same time the efficiency is slightly improved. In summary, based on thermal design of the sCO2 centrifugal compressor, the effects of different flow geometries are analyzed in detail. [ABSTRACT FROM AUTHOR]

The effects of different effective angle of attack motions on flapping foil are considered. Energy extraction characteristics of parallel foils with combined plunging and pitching motions at multiple working conditions are systematically analyzed. The energy extraction processes of dual foil at different effective angle of attack motions and reduced frequencies are simulated, respectively. In the range of parameters discussed in this paper, the increase ofKe improves the energy extraction performance of foil effectively. Every effective angle of attack motion has a frequency which can obtain the optimal extraction performance. The optimal energy extraction working condition is Ke = 2 and k = 0.8, where the extraction efficiency of dual foil achieves 25.8%. The synchronicity of the aerodynamic lift and the plunging motion is increased with increase in Ke. This paper provides a significant reference to the further study and popularization in engineering practice of parallel foils energy extraction. [ABSTRACT FROM AUTHOR]