Thermal conductivity model for nanofiber networks

Abstract

Understanding thermal transport in nanofiber networks is essential for their applications in thermal management, which are used extensively as mechanically sturdy thermal insulation or high thermal conductivity materials. In this study, using the statistical theory and Fourier's law of heat conduction while accounting for both the inter-fiber contact thermal resistance and the intrinsic thermal resistance of nanofibers, an analytical model is developed to predict the thermal conductivity of nanofiber networks as a function of their geometric and thermal properties. A scaling relation between the thermal conductivity and the geometric properties including volume fraction and nanofiber length of the network is revealed. This model agrees well with both numerical simulations and experimental measurements found in the literature. This model may prove useful in analyzing the experimental results and designing nanofiber networks for both high and low thermal conductivity applications.

Solar vapor generation optimization of a carbon‐black/wood‐flour system with strength enhanced by polystyrene

“…The IR camera (FLUKE ti200) was used to capture the temperature distributions at the top of C‐PS/WF by infrared images. The thermal conductivity was measured at the temperature of 20°C by the hot wire method …”

“…The thermal conductivity was measured at the temperature of 20 C by the hot wire method. [46][47][48] The evaporation efficiency (η) is a critical index to assess the evaporation performance, which is calculated by…”

High performance of carbon-particle/bulk-wood bi-layer system for solar steam generation

“…To probe the capacity of the wood to maintain heat, the dry‐wood and wet‐wood thermal conductivities were both measured . The dry‐wood thermal conductivity is about 0.37 W·m −1 ·K −1 measured by hot‐wire method, much smaller than the one of water which is about 0.60 W·m −1 ·K −1 . The low thermal conductivity can inhibit heat transporting into the bulk water.…”

“…[34][35][36][37][38] The dry-wood thermal conductivity is about 0.37 W·m −1 ·K −1 measured by hot-wire method, [39][40][41][42] much smaller than the one of water which is about 0.60 W·m −1 ·K −1 . [43][44][45][46] The low thermal conductivity can inhibit heat transporting into the bulk water. Because the bottom-layer wood floats in the water, it is also essential to study the wet-wood thermal conductivity, which was measured to be of 0.401 W·m −1 ·K −1 , greater than that of the dry wood but less than that of the water.…”

High cross‐plane thermoelectric performance of carbon nanotube sponge films

“…Measurements carried out at high temperatures and Figure S2 also confirm that k ⊥ < k Air (Data S3). This quite low k ⊥ arrives from the small size of pores in CNS, which will reduce the k of air, and also the low k of CNTs along the radial direction, which approximately [42][43][44] Given the pore size in ⊥ direction is comparable with the diameter of CNTs and thus quite smaller than 70 nm (the free-air-molecule mean free path), 45 the k of the confined air in pores could be much smaller than k Air . The k k is also measured by the hot-disk method with a commercial device (TPS 2500 S, Gothenburg Sweden), 46 and result values are exhibited in Figure 4A.…”