Numerical Study of Flow Visualization and Thermal Performance for Pulsating Heat Pipes

Due to the importance of pulsating heat pipes (PHPs) behavior and limitations in conducting experimental studies, numerical simulations are getting more attention. The present work uses numerical simulations for pulsating heat pipes and investigates the thermal performance of closed-loop pulsating heat pipes at different operating conditions, such as evaporator heating power and filling ratio. To this end, water, ethanol, methanol, and acetone are employed as working fluids. A two-dimensional single-loop PHP is used for the present study. Also, the computational Fluid Dynamics (CFD) video technique is employed for flow visualization purposes. Accordingly, a perfect match was observed between the present CFD video clip and previous experimental video-based studies regarding flow patterns and behavior. Moreover, the present study shows how researchers can benefit from developing numerical tools to test pulsating heat pipes behavior at different operating conditions or working fluids without facing the difficulties and limitations of applying laboratory thermal measurement equipment or high-speed cameras. Numerical simulations show that the CFD video clip is very informative for flow visualization. Besides, the simulated clip made capturing phenomena occurring in a pulsating heat pipe much easier. Likewise, the thermal performance investigations at different operating conditions and working fluids were found to be very informative in terms of application and design purposes, especially for experimental studies. By increasing heating power greater than 60 W, circulation velocity was increased for most cases. It should be noted that phase contour videos are inserted at the bottom of the article.