heat transfer enhancement of al2o3/water nanofluid in a double pipe heat exchanger

in this study the heat transfer of al₂o₃/water nanofluid in a double pipe counter flow heat exchanger is investigated both experimentally and numerically. effects of hot and cold stream mass flow rates and temperature and nanoparticle concentration on the heat transfer rate have been investigated. the results indicate that the heat transfer rate increases with increasing in nanofluid temperature and increasing mass flow rate of the cold and hot fluid. computed heat transfer rates of nanofluid are in good agreement with the experimental data. the average relative error between the cfd predictions and experimental data is about 23%.