In this paper, a new dispersion model has been presented and evaluated for the thermal properties of nanofluids in flat tubes. First, by using the results of a multi-objective optimization, which has been implemented by combining the CFD techniques and optimization methods, a new dispersion model is presented for thermal properties of nanofluid in flat tubes, which of course is applicable to circular tubes by setting the tube flattening to zero. This model is a complete function of the important parameters of nanofluid flow in flat tubes, which include the tube flattening, flow rate, volume fraction of nanoparticles and the diameter of nanoparticles. In the next step, the capability and performance of the introduced model is evaluated through the numerical simulations of the nanofluid flow in flat tubes using FORTRAN programming language. The obtained results indicate that the presented dispersion model has a high capability in predicting the thermal properties of different nanofluid flows in flat tubes.
