Hossein Hosseini - Faculty of mechanical engineering, Semnan university, Semnan, Iran,

In the present study, the effects of the shape of quadruple geometry in heat exchangers on the thermal andhydraulic behavior of nanofluids are comprehensively discussed. In this regard, a conventional circular crosssectionpipe along with a pipe with a quadruple cross section is numerically simulated for the nanofluid ofvarious volume concentrations. Hydro-thermal behavior of the geometries is compared for two cases of purewater and nanofluid flow. To evaluate the considered geometries from thermal and hydraulic viewpoints atthe same time factor of PEC is introduced. Based on the results, using nanofluids in circular geometry seemsmore practical. The PR factor was introduced to compare the overall performance of quadratic and circulargeometries for different volume fractions of nanofluids. According to the results, for pure water, using a foursectionpipe instead of ordinary pipes, the overall thermal performance of the heat transfer is improved by%۲.:.

Heat exchanger, Nanofluid, Quadruple, Performance Evaluation Criteria (PEC), PerformanceRatio (PR).