Fig. 4: Experimental verification of reciprocal heat transfer under time modulation.
From: Reciprocity of thermal diffusion in time-modulated systems
a Photo of the system built according to the 3D modulation model in Fig. 3. The movable brass plates are rotated to generate a right-ward moving profile. b Temperature profiles for backward and forward heat transfer. c Experimentally measured temperature profiles along the heat transfer path of the system (dashed green line in a). The scatter points refer to simulated results considering natural air convection and interface thermal resistance. d, e Experimentally measured temperature difference (between two ends of the red segment line in a) changing with time t. The angular velocity of the shaft rotated by the motor is 0.075π rad s−1 (d) and 0.14π rad s−1 (e). The symmetry of time-averaged temperature difference implies the reciprocity of heat flow in Eq. (4).
