磁性液体二阶浮力的理论与实验研究
Theoretical and experimental study on the second-order buoyancy of magnetic fluid

摘要 基于永磁体在磁性液体中受到的二阶浮力的仿真与计算问题，建立了重力场和磁场共同作用下的磁性液体平衡微分方程，推导了二阶浮力的计算公式，提出了一种高精度的二阶浮力的计算方法；将圆柱永磁体等效为同形状的无限薄电流线圈，计算了圆柱永磁体产生的磁场，并根据磁场计算得到二阶浮力；用实验测量了二阶浮力的大小，计算结果和实验结果具有很好的一致性.计算和实验结果表明：不断减小永磁体距离容器壁的距离，二阶浮力不断增大，且距离越小增大得越快.
Abstract：Based on the calculation and simulation of second-order buoyancy experienced by a magnet immersed in magnetic fluid,the Euler equilibrium differential equation of magnetic fluid under gravity field and magnetic field is established，the formula for calculating the second-order buoyancy is deduced and a high-precision method to calculate the second-order buoyancy is presented. The magnetic field generated by the cylindrical permanent magnet is calculated by treating the magnet as an infinite thin current coil, and the second-order buoyancy is got based on the magnetic field obtained from the numerical calculation. An experimental device is built to measure the second-order buoyancy and the experimental results are consistent with the calculation results. Both calculation and experimental results show that second-order buoyancy of the magnet is related to the distance between the permanent magnet and the vessel wall, the shorter the distance, the greater the second-order buoyancy, and the faster the growing pace.