Heat Transport Phenomenon in Fluid Flows over a Stretching Sheet

Abstract

Heat transfer is an ubiquitous process occurring in nature. In an incompressible

uid, this phenomenon has attained broad consideration because of its utilization and developments in industry. These developments include rolling the steel at high temperature, metal extrusion, metal working process, paper production, glass ber production, crystal owing. Ostrach [1] evaluated these applications. Crane [2] investigated 2D ow for a stretched surface. He analyzed Nusselt number and skin friction. Wang [3] considered the 3D ow by utilizing the stretched surface. Later on, this work is extended by many investigators [4 􀀀 15] by considering di erent geometries. Some other applications related to stretching surface may be found in [16 􀀀 19]. However ow analyses over exponentially stretching sheets are examined sparsely [20 􀀀 24]. Magyari and Keller [25] scrutinized the in uence of viscous uid induced by exponentially stretching surface. The heat transport phenomenon in a nano uid ow produced by exponentially stretching sheet was beautifully analyzed 1 by Nadeem and Lee [26]. Nano uids are a classi cation of heat transfer uids which are engineered suspension nanoparticles(1-100nm) dispersed in the uid. Usually base uids incorporate water, organic uids (e.g. ethylene, triethylene and so on) engine oil, polymeric solutions, bio- uids and other base uids. Medium normally utilized as nanoparticles encompass carbon in di erent structures (e.g. carbon nanotubes, graphite, diamond) metals (e.g. copper, silver, gold), metal oxides (e.g titania, zirconia) and functionalized nanoparticles. Utilization of nano uids has found an extensive variety of potential applications. Choi was the rst one to study enhancement of thermal conductivity in nano uids [27]. As indicated by applications, nano uids are listed as heat transfer

uids, bio and pharmaceutical nano uids, medicinal nano uids, environmental nano uids etc. Numerous analysts contemplated how the size, concentration, shape and other properties in uence heat transfer rate of uid. The fusion of specialized liquids which are designed to enhance performance of heat transfer has turned out to be progressively appealing lately. So this subject has tempted vast interest from analysts as a result of fascinating properties and applications [28􀀀37]. Chen et al. [38] presented an approach to estimate thermal conductivity of liquid having nano-sized particles, depend on their rheological properties. Zhou et al. [39] examined aspects of conductivity for di erent variety of mixtures. Heat transfer enhancement and thermal conductivity in nano...