Electronic edition ISSN 1574-0579

Numerical simulation on power generation characteristics of the propeller-type rotating co-axial liquid metal MHD generator

Yanjiao Liu¹ - Weinan Liu^1,2 - Zhenhao Li^1,2 - Aiwu Peng^1,2 - Lingzhi Zhao^1,2

¹ Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China
² University of Chinese Academy of Sciences, Beijing 100049, China

Abstract
The rotating co-axial liquid metal magnetohydrodynamic (MHD) generator is a novel electromagnetic energy conversion device with application potential in wind power generation, tidal current energy and regenerative braking energy recovery. Existing studies have mostly focused on the bladeless configuration, where the flow relies on wall viscous shear, resulting in significant low-speed stagnation zones and Taylor vortex dissipation, leading to limited power generation performance. Numerical simulation and multiphysics?coupled mechanism studies for the insulated propeller configuration are absent. This paper establishes a two-dimensional axis-sectional multiphysics-coupled numerical model of a co-axial liquid metal MHD generator with insulated propeller blades, jointly solving laminar flow, electrostatic field, and external load circuit. The results indicate that the addition of propeller blades effectively eliminates the low-speed stagnation zone. Under identical magnetic field and rotational speed conditions, both the average azimuthal flow velocity and the open circuit voltage are increased by approximately a factor of two. Under load conditions, the current density decreases along the radial direction while remaining uniformly distributed in the circumferential direction, with negligible circumferential leakage current. The output voltage and current increase approximately linearly with magnetic flux density, whereas the output power increases approximately quadratically. A peak conversion efficiency of 82.1 per cent can be achieved under the studied operating conditions. This study reveals the intrinsic mechanism by which propeller blades improve the flow field and enhance power generation performance through active rigid driving, providing a theoretical basis for engineering design and magnetic field regulation strategies. Tables 2, Figs 19, Refs 16.