We present a novel measurement method for the characterization of thermal diodes in a saturated steam atmosphere. A measuring setup has been developed in which two pressure sensors are integrated. Using a developed analytical model, the heat flow, the volume flow, and the cracking pressure are determined from the measured absolute pressures and the pressure difference. The analytical model was verified using a flow through an orifice. We first calculated the volume flow through the orifice, with a diameter of 3 mm, using the Reader-Harris equation and then compared it to experimentally determined values. The experimentally determined values showed a discrepancy of 9%. With the measurement setup, we have characterized a check valve developed for magnetocaloric heat pumps, which has a thermally rectifying behavior. The developed check valve consists of three spring arms, which are radially attached to a valve disk. The heat flow through the check valve in the forward direction is 166 W for water, 239 W for ethanol, and 547 W for methanol at a temperature difference of 1 K. In the reverse direction, the heat flow is −0.03 W at a temperature difference of −1 K. For methanol, this corresponds to a rectification coefficient of more than 18 000.
Method to characterize a thermal diode in saturated steam atmosphere
L. M. Maier, T. Hess, A. Kaube, P. Corhan, A. Fitger, N. Bachmann, O. Schäfer-Welsen, J. Wöllenstein, K. Bartholomé; Method to characterize a thermal diode in saturated steam atmosphere. Rev. Sci. Instrum. 1 June 2020; 91 (6): 065104. https://doi.org/10.1063/5.0006602
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