Modeling of the thermo-mechanical efficiency of the bimetal strip heat engines

14th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications

物理学;能源学

Arnaud, A.^1,2 ; Monfray, S.^1 ; Boughaleb, J.^1 ; Trioux, E.^1,3 ; Boeuf, F.^1 ; Cugat, O.^2 ; Skotnicki, T.^1

ST Microelectronics, Crolles

F38926, France^1

G2Elab, University Grenoble Alpes, Grenoble

F38000, France^2

TIMA, University Grenoble Alpes, Grenoble

F38031, France^3

关键词: Euler buckling;    First order transitions;    Mechanical energies;    Partial derivatives;    Thermo-mechanical;    Thermodynamic cycle;    Thermodynamic potentials;    Thermodynamic systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/557/1/012015/pdf
DOI  :  10.1088/1742-6596/557/1/012015

来源: IOP

【 摘 要 】

This paper presents a theoretical demonstration of the bimetal strip heat engine working, based on the study of the thermo-mechanical instability of the pre-buckled bimetallic beams. Starting from the Euler buckling equation, this paper describes the bimetal strips like classical but non-linear thermodynamic systems, and gives the bistability criterion of such beams. Studying the thermodynamic potentials of these beams helps to evaluate the release of the kinetic energy happening during the beam snap-through, to give the Maxwell relations between each partial derivative of the thermodynamic potentials and to show that the thermal snap-through is a first-order transition according to the Ehrenfest theory. The model is then used to draw the temperature-entropy cycle of the bimetal heat engines and to evaluate the performances of these harvesters (available mechanical energy and thermodynamic cycle efficiency).