Controlling heat ratchet and flow reversal with simple networks

Abstract

We investigate ratcheting heat flow in simple networks consisting of a one-dimensional nonlinear chain with a self-coupled loop when the average thermal bias is zero. The effects of coupling strength and temporally averaged environmental reference temperature on the ratcheting heat flow are discussed. It is found that the total heat flow (THF) will be reversed, while heat flow in the self-coupled loop will disappear with the increase of the coupling strength. A critical coupling strength exists at which the THF disappears, and heat flow exists in the self-coupled loop, i.e., eddy ratcheting heat flow displays. The underlining physical mechanisms are analyzed through phonon spectra and unsteady thermal wave dynamics. Furthermore, a reversal of the THF from a negative to a positive value can be controlled by increasing the reference temperature. A critical reference temperature exists at which the negative THF exhibits a maximum value. Phonons dominate the ratcheting heat flow in the self-coupled loop, while solitons dominate the THF for weak coupling strength. These results can possibly be realized in nanoscale experiments and will help to further understand the thermal information on coupled nanotubes, polymer chains, and biological networks.