Study of Heat Transfer of Periodic Electroosmotic/Pressure Driven Nanofluid Flow in a Microchannel Using the Poisson-Boltzmann Method

In the present study, the electroosmotic and pressure driven flow of nanofluid in a microchannel with homogeneous surface potential is investigated by using the Poisson-Boltzmann equation and the flow field is assumed to be two-dimensional, laminar, incompressible, and steady. Distribution of nanoparticles in the base fluid is assumed to be homogeneous; therefore the nanofluid flow is modeled as a single phase. The thermal conductivity of the nanofluid is modeled by using the Patel model to account for temperature dependency. In order to validate the numerical solution, the results are compared with available analytical solutions and the comparison shows a good match with the results. Then, the effects of different parameters such as ion molar percentage, volume fraction, and nanoparticles’ diameter on the flow field and heat transfer are examined. The results show that by fixing the electric field and increasing the pressure gradient, the local Nusselt number will decrease, and by fixing the pressure gradient and enhancing the electric field, the Nusselt number increases. The average Nusselt number increases about 45, 35 and 25% while nanoparticles’ diameters are 100, 110 and 120nm, respectively. For Γ=0.05, the average Nusselt number increases 10% while ion concentration changes from 10-4 to 10-2. Furthermore, the direction and magnitude of velocity and concavity of the velocity profile can be controlled by choosing a suitable phase angle between electrical and pressure driven flow parameters.