Entropy generation analysis of electroosmotic mixed convection flow in vertical microannulus with asymmetric heat fluxes

Flow formations and heat transfer of electroosmotic flow have significant applications in area of heat exchanger and recently for chemical separation at microlevel. Therefore in this article, exact solutions for entropy generation rate of electroosmotic mixed convection flow in a vertical microannulus subject to asymmetric heat fluxes are presented. Closed form solutions in terms of Bessel's functions are obtained for electric potential, fluid velocity, temperature, skin-friction, Nusselt number and entropy generation after transforming the governing equations into their corresponding dimensionless forms. The obtained solutions are graphically represented using MATLAB software in order to ascertain the role of various pertinent parameters entering flow formation and heat transfer. Results obtained showed that entropy generation rises with increase in radius ratio and electroosmotic force but decreases with increase in slip and buoyancy parameters. Also, irreversibility due to fluid friction or applied electric field is sufficient to dominant the overall entropy generation rate in the presence of strong buoyancy force. On application point of view, fluid velocity, temperature distributions, skin-friction, volumetric flow rate, Nusselt number and entropy generation rate can be optimized by careful selection of governing parameters.