Design optimization of a disk magnetohydrodynamic generator based on the genetic algorithm

Xiuzhen Fang^1,2,3 - Baolin Liu¹ - Manabu Kodama⁴ - Yoshihiro Okuno⁵ - Aiwu Peng^1,2

¹ Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
² University of Chinese Academy of Sciences, Beijing 100049, China
³ North China Institute of Science and Technology, Langtang 065201, Hebei, China
⁴ Tokyo Institute of Technology, Tokyo 152-8550, Japan
⁵ Tokyo Institute of Technology, Yokohama 226-8502, Japan

Abstract
Because of its tangential Faraday current, the working fluid of a disk magnetohydrodynamic (MHD) generator is ionized at nonequilibrium, which can yield higher conductivity at lower gas temperatures and greatly improve the performance of the MHD generator. Additionally, the magnetic field of a disk MHD generator provided by a split superconducting magnet with a simple structure is axial, which can further improve the output power density and the enthalpy extraction rate of the generator. Therefore, disk MHD generators are expected to be applied as high-power static power supplies with compact structure and high-power conversion efficiency. To realize the design and develop a high-performance disk MHD generator, this paper proposes a multiparameter design optimization method based on the genetic algorithm. Taking the enthalpy extraction rate as the optimization objective, the design of the disk channel has been optimized. Using a simple wall profile (straight line type), the anode configuration, load resistance, length of the MHD channel and throat size were optimized to obtain a stable and uniform nonequilibrium plasma in the MHD channel. With the design optimized, the enthalpy extraction rate of the generator was significantly better. Tables 2, Figs 14, Refs 15.