Derényi I, Astumian R D
Department of Surgery, MC 6035, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 Jun;59(6):R6219-22. doi: 10.1103/physreve.59.r6219.
We study the efficiency of one-dimensional thermally driven Brownian ratchets or heat engines. We identify and compare the three basic setups characterized by the type of the connection between the Brownian particle and the two heat reservoirs: (i) simultaneous, (ii) alternating in time, and (iii) position dependent. We make a clear distinction between the heat flow via the kinetic and the potential energy of the particle, and show that the former is always irreversible and it is only the third setup where the latter is reversible when the engine works quasistatically. We also show that in the third setup the heat flow via the kinetic energy can be reduced arbitrarily, proving that even for microscopic heat engines there is no fundamental limit of the efficiency lower than that of a Carnot cycle.
我们研究一维热驱动布朗棘轮或热机的效率。我们识别并比较了三种基本设置，它们的特征在于布朗粒子与两个热库之间的连接类型：（i）同时连接，（ii）时间上交替连接，以及（iii）位置相关连接。我们明确区分了通过粒子动能和势能的热流，并表明前者总是不可逆的，并且只有在第三种设置中，当热机准静态工作时，后者才是可逆的。我们还表明，在第三种设置中，通过动能的热流可以任意减小，这证明即使对于微观热机，也不存在低于卡诺循环效率的基本极限。
