Mechanical Stability Analysis Of High Reliability Thermoelectric Generation Devices

With the increasing energy crisis and environmental pollution problems,thermoelectric generation technology has become a research hotspot with its inherent advantages.In this paper,the mechanical stability of thermoelectric generation devices are analyzed and optimized.Firstly,the numerical simulation analysis of a single thermoelectric module is carried out to explore the influence of the interaction between the thermoelectric modules in the horizontal direction and the vertical direction on the equivalent stress and deformation,and then the method to enhance the mechanical stability of the thermoelectric generation device is obtained.Secondly,the mechanical stability of the two-stage thermoelectric generation device is studied.By constructing the thermalstructural coupling numerical calculation model of the two-stage thermoelectric module.The height of the thermoelectric arm to achieve the optimal mechanical stability is calculated,and the influence of the interaction between two-stage thermoelectric modules on the optimal height of thermoelectric leg is investigated.Finally,a simple two-stage thermoelectric generation device is constructed,and the optimum thermoelectric leg height of the simple two-stage thermoelectric generation device is analyzed.The main research contents are as follows:(1)The interaction between the thermoelectric modules in the horizontal direction increases the equivalent stress,and the interaction in the two directions promotes the stress concentration in the direction.The interaction between the thermoelectric modules in the X direction is more favorable to the stability of the thermoelectric device than the Y direction.When designing thermoelectric generation devices,the number of thermoelectric modules arranged in the X direction should be increased,and the number of thermoelectric modules in the Y direction should be relatively reduced.(2)The interaction between the thermoelectric modules in the vertical direction reduces the maximum equivalent stress and deformation of the thermoelectric module and achieves better mechanical stability.When thermoelectric generation devices need to adopt a three-layer or multi-layer arrangement structure,three or more layers of thermoelectric devices can be directly fabricated,which is more advantageous for mechanical stability of the thermoelectric devices and it can improve service life.(3)The change of the height of the first and second stage thermoelectric legs of the two-stage thermoelectric module will cause the change of the maximum equivalent stress.The maximum equivalent stress decreases first and then increases with the increase of the height of the first-stage thermoelectric legs.The maximum equivalent stress is transferred from the cold end interface to the hot end interface,and minimum value of the maximum equivalent stress is reached at l1=0.62 mm to achieve optimal mechanical stability.(4)The interaction between the thermoelectric modules in the X and Y directions have different effects on the optimal height of thermoelectric legs.The interaction between the thermoelectric modules in the X direction can reduce the optimal height of thermoelectric legs.The interaction between the thermoelectric modules in the Y direction increases the optimal height of thermoelectric legs.(5)The numerical simulation analysis of the simple two-stage thermoelectric generation device shows that the optimal thermoelectric legs combination is l1=0.31 mm,l2=1.69 mm,and the maximum equivalent stress is 268.6 MPa,which optimizes the equivalent stress.The ratio is 6.61%,which can increase its service life.