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

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.

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.