Abstract
Nano fluids are highly capable heat transfer agents with marginal entropy generation and thus are considered to be proficient cooling medium. Keeping in view, the present study is related to entropy analysis of a radioactive rotating nano fluid with prescribed thermal slip at the horizontal surface. The flow problem consists of continuity, linear momentum and energy equations. Such flows find applications in several technological devices such as rotational viscometer, liquid metal pumping, gas-solid fluidized bed and in centrifugal machinery. Three types of nano particles namely copper oxide (CuO), silver (Ag) and gold (Au) are considered with water based fluid. The governing equations of nanofluid are simplified by means of appropriate similarity transformations. Numerical solutions with high precision are obtained using eminent shooting scheme. Bejan number is plotted to present a comparative analysis of entropy generation due to heat transfer and fluid friction. It is found that Bejan number is a decreasing function of nanoparticle volume fraction. The obtained results also reveal that more entropy is generated in the presence of nanoparticles compare to usual fluid flow. Moreover gold nanoparticles generated highest entropy compare to silver and copper oxide nano particles. Thus it is suggested that copper oxide nano particles can be used to enhance heat transfer rate with minimal entropy generation. A suitable agreement with existing published literature is made and an excellent agreement is observed for the limiting case. (C) 2016 Elsevier Ltd. All rights reserved.