Abstract
A new model for entropy generation number in hexagonal microchannel is developed going from the equation proposed by Bejan. The effect of Cu, CuO, Al2O3 and TiO2 mixed with pure water inside the microchannel is evaluated via entropy generation analysis. To show the contribution of entropy heat-transfer generation, Bejan number is also investigated. The effects of heat flux in the range of [2000-12000] W/m(2), and volume fraction and nanoparticles size, respectively, on entropy generation numbers and Bejan number are all evaluated. The results demonstrate that increasing heat flux increases both thermal entropy generation and Bejan number but decreases the frictional entropy production. The results also show that thermal and friction entropy generation numbers exhibit an inverse variation trend when varying volume percentage and nanoparticle diameter.