Double diffusive convective transport and entropy generation in an annular space filled with alumina-water nanoliquid

Abstract

Many of the engineering/industrial applications involving the energy transport undergoes entropy generation which is unavoidable and this leads to degradation of system efficiency. Several researchers working in this field are exploring new ways to minimize the entropy generation so that the efficiency of the system could be enhanced. Motivated by these applications, the current article scrutinizes the rate of entropy generation along with thermal and solutal transport resulting from double-diffusive convective phenomenon in a nanoliquid-filled annular enclosure. Along vertical surfaces of the annulus, the uniform temperature and concentration conditions are specified, while the upper and lower boundaries are maintained as insulated and impermeable. The set of non-linear coupled governing equations in vorticity-stream function form supported by related initial and boundary conditions are computed numerically using time-splitting technique. The influence of various controlling parameters namely the buoyancy ratio (-5 <= N <= 5), Lewis number (0.5 <= Le <= 2), aspect ratio (0.5 <= Ar <= 2) and nanoparticle volume fraction (0 <= phi <= 0.05) on fluid movement, temperature, concentration and entropy production are scrutinized and variation in thermal and solutal dissipation rates, entropy production and Bejan number are graphically illustrated and are discussed with physical interpretation. Through the vast range of computational experiments, it has been found that the quantity of generated entropy in an enclosure is greater during aided flow compared tot hat of opposing case. Further, it has also been found that higher thermal and solutal performance rates with minimal loss of system energy (entropy generation) could be achieved with a shallow annulus.