evaluation of γ-al2o3/n-decane nanofluid performance in shell and tube heat recovery exchanger in a biomass heating plant

the performance of a γ-al 2 o 3 /n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0–7%). compared with pure          n-decane, the obtained results in this research show that by using γ-al 2 o 3 /n-decane nanofluid as coolant at optimum values of particle volume concentration for maximum heat transfer rate (ϕ=0.021) and for maximum performance index (ϕ=0.006), the heat transfer rate and pumping power increased by 10.84%, 13.18% and 6.72%, 2.3%, respectively. increasing particles concentration raises the fluid viscosity, decreases the reynolds number and consequently decreases the heat transfer coefficient. as a result, determining the optimum value of the particle volume fraction of nanofluid as the working fluid, can improve the performance of shell-and-tube heat exchangers.