MHD micropumping of viscoelastic fluids: an analytical solution

An analytical solution is found for examining the effect of a fluid’s elasticity on the performance of MHD micropumps. The test fluid is assumed to be an incompressible viscoelastic fluid obeying the Oldroyd-B model. The flow generated by the Lorentz force is assumed to be laminar, unidirectional, and two-dimensional. The effects of relaxation and retardation times are investigated on the volumetric flow rate. It is concluded that by a decrease in the relaxation time, the pulsatile nature of micropump can be eliminated in its transient phase. At sufficiently low relaxation times, the flow is predicted to monotonically reach its steady value at a much shorter time. By an increase in the retardation time, the pulsatile nature of micropump in its transient phase can also be eliminated and the flow will be more continuous in its steady conditions.