Numerical Simulation on Joule Heating Effect of Electroosmotic Flow in Rectangular Microchannels

Joule heating effect of the temperature fields during electroosmosis in glass and polydimethylsiloxane(PDMS) rectangular microchannels is numerically investigated.The mathematical model of Joule heating effects includes Poisson-Boltzmann equation governing the electric double layer field,the modified Navier-Stokes equations governing the flow field,and the energy equation governing the temperature field due to Joule heating.These fields are strongly coupled via temperature dependent liquid properties.Computations for the temperature field during electroosmosis in the rectangular microchannels are performed with finite element method after simplifying the coupled governing equations.The numerical results indicate that the solution temperature in a PDMS made microchannel is significantly higher than that in a glass made microchannel.And the solution temperature in a bigger PDMS made microchannel(h=48 μm,b=96 μm) is significantly higher than that in a smaller PDMS made microchannel(h=32 μm,b=96 μm).