Research Of Thermalstress And Fatiguelife Of Segmented Thermorlectric Generator

Today, the energy crisis and environmental pollution has a serious impact on countries’ economic development and people’s daily life. To find and develop sustainable green energy has become a common goal and the pursuit of the world. Thermoelectric power generation technology is typical of environmentally friendly energy technology, having no moving parts, small size, no pollution. It can use reasonably solar energy, geothermal energy, ocean thermal energy, industrial waste heat and other low-grade waste heat source to generate electricity. It is environment-friendly equipment. Thermoelectric power generation(TEG) has broad prospects, its application expanding into the civil, industrial and other fields from the high-tech aerospace, military, Bathymetric, medical.Currently, thermoelectric power efficiency is generally 5% to 7%,belowing the 40% of thermal power generation. Low thermoelectric power efficiency to some extent limit the widespread application of thermoelectric power generation technology. The key to improving the efficiency of thermoelectric conversion is searching for high merit material. Since the maximum merit thermoelectric material appears only in a very narrow temperature range. For working in the case of large temperature difference, segmented structure combining different thermoelectric properties of the material can be used, in order to guarantee greater merit in the entire temperature range.Thermoelectric component life is short, reliability is not high. TEG working in the high temperature is most significant. In high temperature environment, the components joints prone to migration and the spread of atomic species cause performance degradation or failure of the thermoelectric material, material mismatch between the thermal expansion coefficients of thermal stress generated easily lead to broken connection. Therefore, it is necessary to analysis thermal stress and life of thermoelectric generators.In this paper, segmented thermoelectric monomer and segmented thermoelectric element are the main targets of study, based on the TEG related theory, finite element analysis method to study.The major work is done as follows:(1) According to the basic theory and structure characteristics of the thermoelectric, determine the geometry, the choice of materials and material properties and variable boundary conditions of the various parts of segment thermoelectric monomer and thermoelectric element(STEG).(2) ANSYS Workbench is used to establish a corresponding geometric segmentation model for thermoelectric coupling analysis and transient structural analysis. Study boundary conditions, arm cross-sectional shape, temperature difference between impact on distribution of thermal stress. Analysis of the thermoelectric properties of optimal conditions and thermal stress distribution.(3) Based thermoelectric generators working conditions to determine the fatigue analysis mechanism and the failure mechanism of TEG. FE-safe software is used to analysis influence on fatigue life of STEG with boundary conditions, in order to provide evidence for improving the device reliability.