变截面温差发电器的工作效率分析及热应力评估OA

[Objective]To address the issues of efficiency below theoretical values and structural reliability under large temperature differences in practical applications of thermoelectric power generation technology,this study investigates the impact of the geometric shape of thermoelectric arms on the performance of variable cross-section thermoelectric generators,clarifies the key factors for efficiency optimization and the distribution patterns of thermal stress,and provides theoretical support for the design of high-performance,high-reliability devices.[Methods]A combination of theoretical modeling and finite element simulation was employed.Theoretically,a model based on the Seebeck effect was constructed,and the coupling relationship between efficiency and key parameters was derived by introducing the shape parameter μ.In simulation,a three-dimensional model containing 8 pairs of thermocouples was established using COMSOL Multiphysics.The performance differences of thermoelectric arms with inclinations of 0°,5°,10°,and 15° were compared.Thermal stress distribution was simulated using a thermoelectric-mechanical-coupling method,and the validity of the model was verified.[Results]When the shape parameter μ>0(trapezoidal structure),the device resistance was reduced and the efficiency improved,with more significant advantages at higher temperature ratios.As the inclination angle of the thermoelectric arm increased from 0° to 15°,the internal resistance rose from 31.9 mΩ to 44.6 mΩ.The maximum conversion efficiency remained similar across different inclination angles,primarily determined by the matching of load resistance and internal resistance.Thermal stress concentrated at the junction between the current-carrying copper plate and the thermoelectric arm and along the edges of the copper plate,with the maximum thermal stress increasing from 55.5 MPa to 59.7 MPa as the inclination angle increased.[Conclusion]Variable cross-section design can improve efficiency by optimizing shape parameters,and the matching of load and internal resistance is key to high-efficiency output.However,increasing the inclination angle exacerbates thermal stress,posing reliability risks.A 10-degree tilt angle is the optimal choice,balancing efficiency and structural safety.The research findings provide quantitative evidence for structural optimization of thermoelectric generators under various operating conditions,facilitating their efficient and reliable application across multiple fields.