Spherical and cylindrical conductive thermal diodes based on VO2

Suraju Olawale Kasali (1) , Jose Ordonez-Miranda (1) , Karl Joulain (1)

1 TNR - Thermique aux Nano échelles et Rayonnement [Institut Pprime]

We theoretically and comparatively study the performance of spherical and cylindrical conductive thermal diodes operating with a phase-change material, whose thermal conductivity significantly changes in a narrow interval of temperatures. Simple analytical expressions are derived for the temperature profiles, heat flows and optimal rectification factors of both diodes. It is shown that the diode geometry has a strong impact on the temperatures and heat flows, but not so much on the diode rectification factor. Optimal rectification factors of 20.8% and 20.7% are obtained for the spherical and cylindrical diodes operating with a temperature difference of 376−300 = 76 K and 376.5-300 = 76.5 K between the terminals of VO2 and a phase invariant material, respectively. These similar rectification factors could be enhanced with a material thermal conductivity exhibiting a higher contrast than that of VO2 . The obtained results can thus be useful to guide the development of phase-change materials able to optimize the rectification of conductive thermal diodes with different geometries.

Domaines: Mécanique des fluides [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Physique Quantique [quant-ph]; Acoustique [physics.class-ph]; Biomécanique [physics.med-ph]; Matériaux; Polymères; Acoustique [physics.class-ph]; Automatique / Robotique; Electromagnétisme; Milieux fluides et réactifs; Energie électrique; Thermique [physics.class-ph]; Vibrations [physics.class-ph]; Physique mathématique [math-ph]

Suraju Olawale Kasali, Jose Ordonez-Miranda, Karl Joulain. Spherical and cylindrical conductive thermal diodes based on VO2. The European Physical Journal Plus, 2019, 134 (7), ⟨10.1140/epjp/i2019-12782-y⟩. ⟨hal-02332339⟩