室温磁制冷活性蓄冷器多孔介质模型及其数值模拟  

Porous Media Model for Active Magnetic Regenerator of Room Temperature Magnetic Refrigeration and Its Numerical Simulation

作　　者：刘敏[1] 俞炳丰[1] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2009年第3期31-35,共5页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(50876082)

摘　　要：鉴于活性蓄冷器作为室温磁制冷核心部件,建立了活性蓄冷器二维复杂多孔介质模型,采用分子场理论计算励(退)磁过程磁性工质温度及磁熵变化,考虑了非Darcy效应、驻留流体、两相热扩散效应、热流边界效应及流体物性非定常的影响.采用有限差分法对两相能量方程进行离散求解.通过计算结果与实验结果的比较对模型进行了验证,认为所建模型能有效反映蓄冷器运行规律并模拟其内部温度分布.数值模拟结果显示:磁场强度变化为2.18 T条件下蓄冷器内金属Gd在其居里点处的温度改变为1.85 K;蓄冷器内部温度梯度明显,微元循环存在显著复叠现象;热流边界效应会导致蓄冷器制冷性能下降,流量较大时物性参数对制冷性能影响较大;在壁面热流通量为5 W/m2的条件下,蓄冷器获得的最大制冷量为201.8 W,对应性能系数为4.79.A two-dimensional complicated porous media model for an active magnetic regenerator of room temperature magnetic refrigeration was established. In the model, the molecular-field theory was adopted to calculate the temperature and magnetic entropy of magnetic material in magnetization （demagnetization） process and the influence of non-Darcy effect, water stored, thermal dispersion effect, heat flux boundary effect and variable fluid physical properties on numerical results was considered. The finite difference method was used to discretize and solve the two-phase energy equations. The present model was verified by experimental results. The numerical results show that the temperature change of Gd at its Curie temperature was 1.85 K under a magnetic field of 2.18 T; distinct temperature grades and overlapping phenomenon of infinitesimal element cycles existed in the regenerator; heat flux boundary effect reduced the refrigeration performance of the regenerator, and fluid physical properties influenced the refrigeration performance of the regenerator greatly at large fluid flux; the regenerator obtained a maximum refrigeration capacity of 201.8 W with a corresponding coefficient of performance of 4. 79.

关 键 词：室温磁制冷 活性蓄冷器 制冷性能 数值模拟 

分 类 号：TB61[一般工业技术—制冷工程] TB66