Release 11.0 Documentation for ANSYS
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This analysis, available in the ANSYS Multiphysics product, can account for the following thermoelectric effects:
Joule heating - Heating occurs in a conductor carrying an electric current. Joule heat is proportional to the square of the current, and is independent of the current direction.
Seebeck effect - A voltage (Seebeck EMF) is produced in a thermoelectric material by a temperature difference. The induced voltage is proportional to the temperature difference. The proportionality coefficient is know as the Seebeck coefficient (α).
Peltier effect - Cooling or heating occurs at the junction of two dissimilar thermoelectric materials when an electric current flows through the junction. Peltier heat is proportional to the current, and changes sign if the current direction is reversed.
Thomson effect - Heat is absorbed or released in a non-uniformly heated thermoelectric material when electric current flows through it. Thomson heat is proportional to the current, and changes sign if the current direction is reversed.
The ANSYS program includes a variety of elements you can use to model thermal-electric coupling. Table 2.3: "Elements Used in Thermal-Electric Analyses" summarizes them briefly. For detailed descriptions of the elements and their characteristics (DOFs, KEYOPT options, inputs and outputs, etc.), see the Elements Reference.
LINK68, PLANE67, SOLID69, and SHELL157 are special purpose thermal-electric elements. The coupled-field elements (SOLID5, SOLID98, PLANE223, SOLID226, and SOLID227 ) require you to select the element DOFs for a thermal-electric analysis: TEMP and VOLT. For SOLID5 and SOLID98, set KEYOPT(1) to 0 or 1. For PLANE223, SOLID226, and SOLID227, set KEYOPT(1) to 110.
Table 2.3 Elements Used in Thermal-Electric Analyses
| Elements | Thermoelectric Effects | Material Properties | Analysis Types |
|---|---|---|---|
LINK68 - Thermal-Electric Line PLANE67 - Thermal-Electric Quadrilateral SOLID69 - Thermal-Electric Hexahedral SOLID5 - Coupled-Field Hexahedral SOLID98 - Coupled-Field Tetrahedral SHELL157 - Thermal-Electric Shell | Joule Heating | KXX, KYY, KZZ RSVX, RSVY, RSVZ DENS, C, ENTH | Static Transient (transient thermal effects only) |
PLANE223 - Coupled-Field Quadrilateral SOLID226 - Coupled-Field Hexahedral SOLID227 - Coupled-Field Tetrahedral | Joule Heating Seebeck Effect Peltier Effect Thomson Effect | KXX, KYY, KZZ RSVX, RSVY, RSVZ DENS, C, ENTH SBKX SBKY, SBKZ PERX, PERY, PERZ | Static Transient (transient thermal and electrical effects) |
The analysis can be either steady-state (ANTYPE,STATIC) or transient (ANTYPE,TRANS). It follows the same procedure as a steady-state or transient thermal analysis. (See Steady-State Thermal Analysis and Transient Thermal Analysis in the Thermal Analysis Guide.)
To perform a thermal-electric analysis, you need to specify the element type and material properties. For Joule heating effects, you must define both electrical resistivity (RSVX, RSVY, RSVZ) and thermal conductivity (KXX, KYY, KZZ). Mass density (DENS), specific heat (C), and enthalpy (ENTH) may be defined to take into account thermal transient effects. These properties may be constant or temperature-dependent.
A transient analysis using PLANE223, SOLID226, or SOLID227 can account for both transient thermal and transient electrical effects. You must define electric permittivity (PERX, PERY, PERZ) to model the transient electrical effects. A transient analysis using LINK68, PLANE67, SOLID69, SOLID5, SOLID98, or SHELL157 can only account for transient thermal effects.
To include the Seebeck-Peltier thermoelectric effects, you need to specify a PLANE223, SOLID226, or SOLID227 element type and a Seebeck coefficient (SBKX, SBKY, SBKZ) (MP). You also need to specify the temperature offset from zero to absolute zero (TOFFST). To capture the Thomson effect, you need to specify the temperature dependence of the Seebeck coefficient (MPDATA).
PLANE67 and PLANE223 assume a unit thickness; they do not allow thickness input. If the actual thickness (t) is not uniform, you need to adjust the material properties as follows: multiply the thermal conductivity and density by t, and divide the electrical resistivity by t.
Be sure to define all data in consistent units. For example, if the current and voltage are specified in amperes and volts, you must use units of watts/length-degree for thermal conductivity. The output Joule heat will then be in watts.
For problems with convergence difficulties, activate the line search capability (LNSRCH).
See Sample Thermoelectric Cooler Analysis (Batch or Command Method) and Sample Thermoelectric Generator Analysis (Batch or Command Method) for example problems.