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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-517-2

5-6th Thermal and Fluids Engineering Conference (TFEC)
May, 26–28, 2021 , Virtual

MODELING BRIDGMAN HEATING IN THERMOELECTRIC GENERATORS

Get access (open in a dialog) pages 259-268
DOI: 10.1615/TFEC2021.cmd.036778

Аннотация

Thermoelectric generators (TEGs) are small-scale, solid-state devices that converts heat flux into electrical energy through the Seebeck effect. To reliably predict the behavior of these devices under a large range of operational conditions, numeric modeling is often pursued. Within most numerical models, a heat source term is often neglected due to the difficulty of spatially resolving the current density vector. This term represents the Bridgman effect, which is volumetric source term resulting from the gradient of current density vector in the thermoelectric material caused as the system simultaneously tries to maintain both a steady thermal gradient and charge distribution. To investigate the effect of Bridgman heating on the predictions of numeric models of TEGs, a fully coupled thermoelectric model was constructed in ANSYS CFX using the built-in Electromagnetic Model. This model was then used to predict the thermal and electrical performance of single and multi-junction TEGs. Heat generation terms within the energy equation included volumetric expressions for Joule, Thomson and Bridgman heating, and a flux expression for Peltier heating, as well as temperature-dependent thermophysical material properties. The role of Bridgman effect on thermoelectric performance predictions is studied by considering and neglecting the Bridgman effect in the computational analysis. In regions where large current density gradients existed, namely at interfaces between the interconnectors and thermoelectric materials, there is localized Bridgman heating. By considering Bridgman heating, global energy imbalances decreased in all scenarios, upward of 47%, and was more perceptible when the device operates at larger temperature gradients and higher current density values.
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