Experimental Investigation on Heat Transfer and Pressure Drop of CNT-Base Oil Nano-Fluid Flow in Rectangular Channels under Constant Wall Temperature

Abstract

An experimental investigation has been carried out to study the heat transfer and pressure drop characteristics of MWCNT-Base oil nano-fluid flow inside horizontal rectangular channels under constant wall temperature. The temperature of the tube wall was kept constant at around 95 °C to have isothermal boundary condition. The required data were acquired for laminar fully developed flow inside round and rectangular channels. The effect of different parameters such as mass velocity, aspect ratio of rectangular channels and nano-particles concentration on heat transfer coefficient and pressure drop of the flow is studied. Observations show that the heat transfer performance is improved as the aspect ratio is increased. Also, increasing the aspect ratio will result in the pressure drop increasing. In addition, the heat transfer coefficient as well as pressure drop is increased by using nano-fluid instead of base fluid. Furthermore, the performance evaluation of the two enhanced heat transfer techniques studied in this investigation showed that applying rectangular channels instead of the round tube is a more effective way to enhance the convective heat transfer compared to the second method which is using nano-fluids instead of the base fluid.