Non-Fourier heat conduction study for steady states in metallic nanofilms

Haidong Wang,Zengyuan Guo,Jinhui Liu,Koji Takahashi

doi:10.1007/s11434-012-5288-7

Abstract

As a fundamental theory of heat transfer, Fourier’s law is valid for most traditional conditions. Research interest in non-Fourier heat conditions is mainly focused on heat wave phenomena in non-steady states. Recently, the thermomass theory posited that, for steady states, non-Fourier heat conduction behavior could also be observed under ultra-high heat flux conditions at low ambient temperatures. Significantly, this is due to thermomass inertia. We report on heat conduction in metallic nanofilms from large currents at low temperatures; heat fluxes of more than 1×1010 W m−2 were used. The measured average temperature of the nanofilm is larger than that based on Fourier’s law, with temperature differences increasing as heat flux increased and ambient temperature decreased. Experimental results for different film samples at different ambient temperatures reveal that non-Fourier behavior exists in metallic nanofilms in agreement with predictions from thermomass theory.

Highlights

Fourier studied many experimental results on heat conduction summarized in his famous Fourier’s law, advancing a linear relationship between heat flux and temperature gradient [1]
The thermomass theory posited that, for steady states, non-Fourier heat conduction behavior could be observed under ultra-high heat flux conditions at low ambient temperatures
We report on heat conduction in metallic nanofilms from large currents at low temperatures; heat fluxes of more than 1×1010 W m 2 were used

Summary

Experimental setup

According to eq (7), the steady non-Fourier heat conduction occurs only under ultra-low temperature, ultra-high heat flux conditions. Metallic nanofilms can sustain large heating currents with maximum heat fluxes of more than 1010 W m 2. Co-workers in Kyushu university of Japan prepared high-qualified Au nanofilms using electron-beam physical vapor deposition. A two-stage vacuum pumping system is used to maintain the air pressure below 10 4 Pa around the nanofilms, and eliminate heat convection. Fashioned to isolate the device from ambient radiation. Two high-precision digital voltmeters (Keitheley 2002) and a DC power supply (Advantest R6243) are used to measure the resistance of Au nanofilm using a four-probe method

One dimensional heat conduction model

Measurement of electronic and thermal conductivities of Au nanofilms

Measurement by large current heating

Experimental results