Torque Transmission Efficiency of Magnetic Coupling Drives in Sealed Containers

Abstract

Magnetic coupling drives provide a highly reliable, non-contact means of torque transmission for sealed containers, where conventional mechanical shaft penetration frequently introduces severe operational risks such as fluid leakage, environmental contamination, accelerated seal wear, and internal pressure instability. These characteristics make magnetic couplings relevant to demanding industrial applications, including sealed mixers, high-pressure vessels, chemical processing equipment, and laboratory reactors. However, existing performance evaluations predominantly focus on maximizing transmissible torque or optimizing static magnetic structure design. Consequently, the combined influence of the operational air gap, isolation wall thickness, dynamic load torque, and thermal loss on overall transmission efficiency remains insufficiently quantified. To address this limitation, this paper proposes a novel gap--wall--load calibrated evaluation framework. This approach seamlessly integrates analytical torque modeling, rigorous finite element calibration, dynamic slip-risk assessment, thermal-loss correction mechanisms, and repeated experimental validation procedures. Two public datasets, encompassing permanent magnet synchronous motor torque data and magnetic coupling coefficient data, are utilized with controlled laboratory bench testing to evaluate the proposed model's performance. Results demonstrate that the proposed framework significantly improves the calculated average efficiency from 77.9% ± 3.1% to 86.8% ± 1.7% on Dataset A, and from 75.6% ± 3.4% to 83.1% ± 1.9% on Dataset B, compared with the traditional cylindrical coupling baseline. Furthermore, the prediction error is substantially reduced to 4.9% ± 0.7% and 5.3% ± 0.8% across the two respective datasets. Ultimately, these findings strongly indicate that sealed-wall attenuation and load-dependent stability must be considered jointly when designing leakage-free magnetic coupling transmission systems.