Overall thermal performance of ferrofluidic open loop pulsating heat pipes: An experimental approach

Pulsating heat pipes (PHPs) are simple, cheap, and efficient heat transfer devices. They have applications in electronic cooling. In the present research, an experimental investigation is conducted on startup and steady thermal performances of open loop pulsating heat pipes (OLPHPs). Effects of working fluid, heat input, non-condensable gases (NCGs), ferrofluid concentration, magnets location, and inclination angle on the thermal performance of OLPHPs have been considered. Obtained results show that using ferrofluid can improve the thermal performance in steady state condition. Furthermore, applying a magnetic field enhances the heat transfer characteristics of ferrofluidic OLPHPs in both startup and steady state conditions. At 20 W heating power and startup condition, higher NCGs have the best performance in the presence of magnetic field. However, in the absence of magnetic field opposite trend is observable. In the case of steady thermal performance in both presence and absence of magnetic field, lower amounts of NCGs lead to better thermal performance. Best heat transfer capability is achieved at around 67.5° inclination angle relative to the horizontal axis for all of the working fluids. With the application of magnetic field in different locations of the OLPHPs, one can adjust their thermal performance to the desired value.