Configuration of the thermal rectification system consisting of the dielectric-coated silicon carbide (SiC) plate and the uncoated SiC plate (dimensions: g 0 + t 3 = 100 nm, t3 is variable, temperatures: TH = 500 K and TL = 300 K, permittivities: ɛ 1 and ɛ 2 are referred to Ref. 34. ɛ 3 is variable).
Net spectral heat fluxes of the p-polarized evanescent wave for the forward and reverse temperature-biased scenarios. (a) ɛ 3 = 2, t 3 = 10 nm, (b)ɛ 3 = 14, t 3 = 1 nm, (c) ɛ 3 = 14, t 3 = 10 nm. (a) and (b) meet Eq. (9), while (c) does not meet it (solid lines: forward biased scenario, dashed lines: reverse biased scenario).
(a) Relationship of the coating permittivity and thickness and (b) rectifying coefficients that are plotted when the rectifying coefficients are larger than 0.4. The solid curve is the result of Eq. (9) derived for maximizing the rectification, and circles are the results of the heat flux calculation in (a). Crosses and circles represent the evanescent p-polarization contribution and all-components contributions; p- and s-polarized evanescent and propagation waves, respectively, in (b).
Vacuum gap dependence characteristics of rectifying coefficients when the coating parameters are fixed with ɛ 3 = 2 and t 3 = 10 nm [Fig. 2(a)]. The solid curve includes all-components contributions; p- and s-polarized evanescent and propagation waves, while the dashed line includes only the p-polarized evanescent wave contribution.
Normalized integrand Z distributions (black-red-white colorscale) of Eq. (3b) for the p-polarized evanescent wave in the ω-β plane when the coating has parameters of ɛ 3 = 2 and t 3 = 10 nm [Fig. 2(a)]. Dispersion curves (green lines) of Eq. (10) are also plotted. (a) Forward biased scenario and (b) reverse biased scenario.
(a) Maximum achievable thermal rectifying coefficients (solid line) with variation of the high temperature TH , holding TL = 300 K when (b) the coating thickness t 3 is adjusted (solid line) with ɛ 3 = 2. The temperature dependence characteristics of rectifying coefficients with t 3 = 10 nm (dashed line) and 25 nm (dotted line) are also presented. The three curves (solid, dashed, and dotted lines) include all-components contributions; p- and s-polarized evanescent and propagation waves, while the dashed-dotted line includes only the p-polarized evanescent wave contribution in (a).
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