Experimental investigation of graphene oxide nanofluid on heat transfer enhancement of pulsating heat pipe

Pulsating heat pipes (PHPs) are heat transfer devices which can be used in different energy systems Improvement in thermal performance of PHPs will lead to higher efficiency of systems which PHPs are used. In this study, an experimental investigation was performed on the thermal performance of a pulsating heat pipe by using graphene oxide nanofluid as working fluid. Four concentrations of graphene oxide ( 0.25, 0.5, 1, and 1.5 g/lit) in water as base fluid were used in PHPs. Results indicate that adding graphene oxide sheets increased thermal conductivity and viscidity of DI water. Moreover, graphene oxide can decrease thermal resistance of PHP up to 42%. In addition, at high concentration (1.5g/lit), thermal resistance increase which is attributed to increasing in dynamic viscosity of nanofluid.