Griebl M, Dornseifer T, Neunhoeffer T. Numerical simulations in fluid dynamic. Philadephia: SIAM;1998.
Daungthongsuk W, Wongwises S. A critical review of convective heat transfer of nanofluids. Renewable and Sustainable Energy Reviews 2007;11(5):797-817.
Wang XQ, Mujumdar AS. Heat transfer characteristics of nanofluids: a review. International Journal of Thermal Sciences 2007;46(1):1-19.
Al-aswadi AA, Mohammed HA, Shuaib NH, Campo A. Laminar forced convection flow over a backward facing step using nanofluids. International Communications in Heat and Mass Transfer 2010;37(8):950957.
Tikrit Journal of Engineering Sciences (2017) 24(1) 38-49
Laminar Mixed Convective Nanofluid Flow in a Channel with Double Forward Facing Steps: A Numerical Simulation Study
|Omar A. Hussein|
|Mechanical Eng. Dept., Tikrit University, Iraq|
Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum, and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2, and ZnO, with different volume fractions in range of 1-4% and different nanoparticles diameter in the range of 20 – 80nm in base fluid (water) were used. Numerical investigations are conducted using finite volume method. In this study, different parameters such as the geometrical specifications (different steps heights in the range of h1= 0.01m-0.04m and h2 = 0.03m-0.06m for FFS) are used. Different Reynolds numbers in the range of 50-2000 (laminar flow) are investigated to identify their effects on the heat transfer and fluid characteristics. The results indicate that SiO2-water has the highest Nusselt number followed by -water, -water and ZnO-water. The Nusselt number increases as the volume fraction increases but it decreases as the nanoparticles diameter increases. The velocity magnitude increases as the density of nanofluids decreases. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase.
Keywords: Mixed convection, forward-facing double steps, heat transfer enhancement, nanofluids.