We have studied numerical simulation method to calculate the maximum torque forces between a superconductor and a multiple-pole permanent magnet circuit. For practical applications of superconducting mixers used in ultra-clean environment such as medical use, the enhancement of the transferable torque forces is critically important. We used commercial Dy-Ba-Cu-O bulk superconductors and four different permanent magnet circuits. The maximum torque forces were estimated based on the idea that it is the product of the effective length between two magnetic peaks and the pinning force. It was found that the results of numerical calculations were in good agreement with the empirical data, showing that our simple model is useful for simulation of the torque forces.
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