Fabrication and Characterization of Acicular Micro-Textured Copper Sheet Device for Low-Temperature Heat Radiation

Abstract

An acicular microtextured sheet was developed as a heat radiation device from the high-temperature source to the cooling medium in the infrared (IR) spectrum. The copper surface was modified by acicular micro-texturing to place a semi-regular micro-/nano-cone structure onto it. FT-IR (Fourier transformation IR) spectroscopy was utilized to measure the transmittance diagram in near-IR to far-IR wavelengths. The wavelength (λ) of 6.7 μm, where the highest absorbance valley was detected in the diagram, was equivalent to the doubled size of the micro-cone average height, with Have = 3.3 μm; λ ~ 2 × Have. The electromagnetic waves in the far-IR wavelength were emitted by acicular micro-textured metallic sheets. The heat radiation transfer experiment was performed to describe this low-temperature heat radiation behavior. No temperature rise was detected on the black-colored polycarbonate (BC-PC) plate away from the bare copper sheet without textures, located on the high-temperature source. The temperature increased by 4 K on the BC-PC plate using the acicular textured copper sheet device. The emitter temperature also decreased significantly by 50 K or 50% of the heat source temperature.

Heat Transportation by Acicular Micro-Textured Device with Semi-Regular Alignment

“…The FT-IR measurement setup is schematically depicted in Figure 5a. The detector was placed onto the specimen to measure the transmittance of electromagnetic waves or T (λ)in Geometric characterization on the unit cell size and alignment by picture processing and computer geometry [22,25]. the wavelength (λ) range from the visible light to far-IR.…”

“…As discussed in [22], the measured spectra on the IR-emission at the five positions on the LL-specimen were compared among them. Although the measured intensities deviate from each other, the measure spectra were equivalent to E (λ)in Figure 10.…”

“…The average wavelength of emission spectra, λ ave , and the standard deviation Δλ in each E (λ) are estimated from Figure 11 and listed in Table 2. The measured IR-emittance by the FT-IR for the LL-type specimen [22,24,25].…”

“…Extension of the interfacial area improves the overall heat penetration factor through the interface [15,16]. In addition, the acicular micro-textured interface is cooled more rapidly than that on the bare copper sheet as stated in [17]. The topological design on the micro-textured interface has large influence on the local convection heat transfer to the coolants.…”

“…In particular, the nano-structured, the meta-material, and the concave micro-textured interfaces [19][20][21] provided a way to make low-temperature heat radiation. As discussed in [17,22,23], the heat radiation takes place at 323 K in air and in vacuum from the acicular micro-textured emitter to the objective body. No temperature rose on the object surfaces when using the bare copper substrate without acicular microtextures.…”