对光纤中磁流体在梯度磁场作用下的光透射特性进行了研究,提出光纤中磁流体的光透射率变化主要来源于梯度磁场引起的磁流体密度分布变化。根据郎之万函数和流体理论,推导了光纤中磁流体在梯度磁场作用下的密度分布,并根据Beer-Lambert定律,得到磁流体光功率透射衰减和纳米粒子局部密度的关系,从而建立光纤中磁流体在梯度磁场作用下光透射特性的理论模型。进而对光纤中磁流体在不同梯度磁场作用下的光透射功率进行数值分析,得到不同磁场强度和磁场梯度下光纤中磁流体透射功率的变化规律。最后将数值分析的结果和实验数据进行对比,验证了模型的合理性,同时也验证了梯度磁场作用下磁流体光透射功率的变化主要来源于磁流体密度分布变化的推论。

The work studies the light transmission characteristics of the ferrofluid in the fiber in the gradient magnetic field,and proposes the idea that the change of light transmisson rate of ferrofluid in the fiber comes mainly from the change of the ferrofluid density distribution caused by the gradient magnetic field. According to the Langevin function and the fluid theory, we derive the density distribution of magnetic fluid in the fiber in the gradient magnetic field. And based on the Beer-Lambert law, we get the relationship between the attenuation of optical transmission power and local density of the nanoparticles. Then we establish the theoretical mode of the light transmission characteristics of the ferrofluid in the fiber in the gradient magnetic field. And then we perform the numerical analysis of the light transmission power of ferrofluid in the fiber in the different gradient magnetic field, and gain the variation of transmission power value of the magnetic fluid in the fiber in different magnetic strength and magnetic field gradient. Finally, we compare the numerical results and experimental data, which verifies the rationality of the model and the inference that the change of light transmission power of the ferrofluid in the gradient magnetic field is caused mainly due to the changing density distribution of ferrofluid.