AI 中文总结
本研究建立双温度磁流体动力学模型，验证了电磁驱动离心机（EMDCs）的分离性能优于接近材料速度极限的剪切驱动离心机，挑战了λ<1的论断，提出可通过增大λ径向分布提升分离效果。
AI 中文摘要
电磁驱动离心机（EMDCs）利用洛伦兹力旋转流体，但其分离性能受与电磁驱动耦合的热耗散限制，这是因为局部离心强度与λ=mV_θ²/(2k_B T)成正比，λ将驱动组分分离的定向动能与平滑浓度梯度、抵消分离的热能进行比较。本研究建立了简化的双温度磁流体动力学模型，以确定径向几何、电流密度和磁场强度如何控制决定λ的旋转与加热耦合演化。该模型通过氩（Ar）及氩/氪（Ar/Kr）实验验证，实验覆盖电流密度最高达15 kA/m²、磁场最高达0.57 T、进料压力0.5-3 Torr、环隙尺寸1-5 cm。结果显示，与壁面剪切离心机相比，体积洛伦兹驱动能在更大流体体积径向范围内维持更高的λ，从而产生更大的局部组分偏移，尽管其峰值λ更低。对⁴⁰Ar/³⁶Ar同位素混合物的模拟表明，当电磁力与几何共同优化时，EMDCs在面积平均λ更低的情况下，可超过接近材料速度极限运行的剪切驱动离心机的分离性能。这些结果挑战了“弱电离等离子体离心机受粘性耗散约束至λ<1”的论断，表明可通过增大λ的径向分布而非最大化其峰值或面积平均值，实现增强的径向质量分离。
英文摘要
Electromagnetically driven centrifuges (EMDCs) rotate fluids using the Lorentz force, but their separative performance is limited by thermal dissipation that is coupled to electromagnetic forcing. This follows because local centrifugal strength is characterized by λ=mV_θ^2/2k_B T, which compares directed kinetic energy that drives species separation to thermal energy that smooths concentration gradients and counteracts separation. In this work, we develop a two-temperature magnetohydrodynamic model to determine how radial geometry, current density, and magnetic field strength control the coupled evolution of rotation and heating that dictates λ. The model is benchmarked against Ar velocity, temperature, and pressure measurements spanning current density up to 15 kA/m2, magnetic field up to 0.57 T, feed pressures of 0.5-3 Torr, and annulus sizes of 1-5 cm. The results show that volumetric Lorentz forcing sustains elevated λ, and therefore greater local compositional shifts throughout a larger radial portion of the fluid volume than wall-bounded shear centrifuges, despite producing a lower peak λ. Simulations of a 40Ar/36Ar isotopic mixture demonstrate that, when electromagnetic force and geometry are jointly optimized, EMDCs can approach or match the separative performance of shear-driven centrifuges operating near material speed limits while requiring lower area-averaged values of λ, and can sustain greater radial compositional shifts than the SDC reference over much of the annulus. These results challenge assertions that viscous dissipation constrains weakly ionized plasma centrifuges to λ<1, and indicate that enhanced radial mass separation can be achieved by broadening the radial region over which λ remains elevated rather than maximizing its peak or area-averaged value.
