Investigation of flow and heat transfer of nanofluid in a diverging sinusoidal channel

Using of nanofluids and ducts with corrugated walls are both supposed to enhance heat transfer, by increasing the heat transfer fluid conductivity and the heat transfer area respectively. Use of a diverging duct with a jet at inlet section may further increase heat transfer by creating recirculation zones inside the duct. In this work two-dimensional incompressible laminar flow of a nanofluid entering a diverging channel with sinusoidal walls through a jet at inlet section, is numerically investigated. Effects of aspect ratio (duct-to-jet height ratio), wall-wave amplitude, wall wavelength, Reynolds number, nanoparticle volume fraction and the size of nanoparticles on the flow structure and heat transfer are investigated. The results show that by increasing the Reynolds number, wall wave amplitude and nanoparticle volume fraction, the duct averaged Nusselt number will increase, while the wall wavelength and the particle size have an adverse effect. The inlet jet has the strongest effect on heat transfer at the aspect ratio of 4.