Abstract
Thermally developing mixed electroosmotically and pressure-driven flow in a triangular micro-duct with a step change wall temperature is investigated. Both axial conduction (Graetz problem extended) and Joule heating effects are taken into consideration. A new higher order accurate method is proposed. The proposed method is based on pseudo spectral Galerkin approach and the eigenfunctions of the Helmholtz equation for a triangular geometry. Convergence of the method is investigated and the effect of the Péclet (Pe) number, Joule heating and Debye–Hückel parameter on the temperature distribution and Nusselt number (Nu) are discussed in detail.