Wave rotor as a pressure exchanger for lower rotational speed and lower shaft work in a supercritical carbon dioxide Brayton cycle

• Published in: Energy conversion and management Vol. 277; p. 116578
• Main Authors: Chan, Shining, Yao, Lichao, Fu, Qingfei, Chen, Yeyu, Liu, Huoxing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: Rotational speed; Shaft work; Supercritical carbon dioxide Brayton cycle; Unsteady pressure wave; Wave rotor; Shaft work; Wave rotor; Unsteady pressure wave; Supercritical carbon dioxide Brayton cycle; Rotational speed
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2022.116578

[Display omitted] •Wave rotor is tried as pressure exchanger for supercritical carbon dioxide.•Unsteady pressure waves in wave rotor does not take high rim speed to do work.•Wave rotor reduce turbomachinery’s rotational speed to 8 % and shaft work to 4 %•Wave rotor achieve comparable efficiency and size to turbomachinery. Supercritical carbon dioxide Brayton cycle is emerging as a solution to effective and clean power resources, and the pressure exchanger is a critical part of such cycle. While turbomachinery is the conventional technology of such pressure exchangers, it sustains high shaft work and suffers from especially high rotational speed, which is a key challenge. This work proposed a wave rotor for supercritical carbon dioxide pressure exchanger as an alternative technology of the turbomachinery. Numerical simulation results demonstrate that a wave rotor compresses and expands supercritical carbon dioxide with unsteady pressure waves, so it does not take a high rim speed to do the compression or expansion work like turbomachinery, and a low rotational speed and a low shaft work are available then. According to the design results for a practical compression ratio at 1.93 and a massflow rate at 2.30 kg/s, the wave rotor reduces the rotational speed to 8 % and the shaft work to 4 % of equivalent turbomachines, and the wave rotor has comparable efficiency and size to equivalent turbomachines. This work provides the special advantage and suitability of the wave rotor as a pressure exchanger of the supercritical carbon dioxide Brayton cycle.