The effect of temperature on viscous friction and the performance of a Brownian heat engine

TL;DR

This study investigates how temperature-dependent viscosity influences the transport and efficiency of a Brownian heat engine, revealing enhanced unidirectional motion and efficiency with temperature-dependent friction.

Contribution

It introduces a model where viscous friction decreases exponentially with temperature, highlighting its impact on Brownian engine performance and thermodynamic efficiency.

Findings

Temperature-dependent viscosity enhances unidirectional motion.

Efficiency of the heat engine increases with temperature-dependent friction.

Constant viscosity favors higher refrigerator performance.

Abstract

We explore the transport features of a Brownian particle that walks in a periodic ratchet potential that is coupled with a spatially varying temperature background. Since the viscous friction of the medium decreases as the temperature of the medium increases, any reasonable exploration regarding the thermodynamic features of the Brownian engine should take into account the role of temperature on the viscosity of the fluid. In this work, we study this effect of temperature by considering a viscous friction that decreases exponentially as the background temperature increases. Our result depicts that the Brownian particle exhibits a fast unidirectional motion when the viscous friction is temperature dependent than that of constant viscous friction. Moreover the efficiency of this motor is considerably enhanced when the viscous friction is temperature dependent. On the hand, the motor exhibits a higher performance of the refrigerator when the viscose friction is taken to be constant.