论文标题
粘弹性浴中胶体热发动机的工作提取和性能
Work extraction and performance of colloidal heat engines in viscoelastic baths
论文作者
论文摘要
嵌入流体中的胶体颗粒可以通过光学陷阱施加的一系列环状变换来用作微观热发动机。当周围的介质是粘弹性时，我们研究了一种用于这种布朗发动机的模型，该模型将粒子动力学带有内存摩擦。我们分析了流体的松弛时间对有限时间的Stirling循环下胶体发动机性能的影响。我们发现，由于粘弹性流体中摩擦的频率依赖性，与具有相同零剪切粘度的粘性环境相比，发动机传递的平均功率及其效率可以得到高度提高。此外，随着流体松弛时间的增加，发动机可以传递正功率输出的周期时间间隔。我们的结果揭示了布朗尼加热发动机在复杂流体中经历的摩擦瞬时行为的重要性，当有限持续时间的热力学循环驱动时，这种摩擦均无法忽略。
A colloidal particle embedded in a fluid can be used as a microscopic heat engine by means of a sequence of cyclic transformations imposed by an optical trap. We investigate a model for the operation of such kind of Brownian engines when the surrounding medium is viscoelastic, which endows the particle dynamics with memory friction. We analyze the effect of the relaxation time of the fluid on the performance of the colloidal engine under finite-time Stirling cycles. We find that, due to the frequency-dependence of the friction in viscoelastic fluids, the mean power delivered by the engine and its efficiency can be highly enhanced as compared to those in a viscous environment with the same zero-shear viscosity. In addition, with increasing fluid relaxation time the interval of cycle times at which positive power output can be delivered by the engine broadens. Our results reveal the importance of the transient behavior of the friction experienced by a Brownian heat engine in a complex fluid, which cannot be neglected when driven by thermodynamic cycles of finite duration.
