Numerical Analysis of Effective Thermal Conductivity of Microwire Array Element

We have used the finite-element method to calculate numerically the equations of electrical and thermal transport. The thermal conductivity of a wire array is analyzed. The influence of the wire array on the effective thermal conductivity of the element is discussed. The effective thermal conductivity decreases as the wire diameter is reduced. Decreasing the packing density significantly reduces the effective thermal conductivity. In the classical regime, the ratio of the effective electrical conductivity to the effective thermal conductivity of the wire array can be expressed as a function of packing density; this ratio decreases as the packing density decreases. The ratio for a wire array with realistic parameters is similar to that of bulk bismuth. Therefore, to improve the thermoelectric figure of merit, it is critical to enhance the intrinsic power factor in a wire by exploiting thermomagnetic or quantum effects.