The dissipation of intense heat flux is critical in many fields including computing, renewable energy, and aerospace. Oscillating Heat Pipes (OHPs), also referred to as Pulsating Heat Pipes (PHPs), have shown promise in addressing heat dissipation challenges and have been the subject of extensive research investigations. A wide variety of experimental investigations have been previously reviewed in the literature to highlight trends in performance. However, the mechanisms behind these trends are not well understood due to the complexity of OHP operation, which in some cases leads to results that appear to contradict trends in previous experiments.

In the current investigation, four facets of operation that are not currently well understood are reviewed and investigated further using a range of models and experimental results from the literature to provide insight into OHP performance trends. The analysis indicates the confusion in the literature regarding the dominance of sensible or latent heat transfer occurred due to the heat transfer being evaluated at different locations in the OHP. Spring-damper-mass (SDM) analogies are used to analyze possible mechanisms for the transition between small amplitude and large amplitude operation, and the changes in the liquid distribution that occur in OHPs with changes in heating. Additionally, it is shown that the onset of circulation in symmetrical, bottom heated OHPs can be caused by a Rayleigh-Taylor instability, and that circulation flow supplies an additional pumping pressure that generally improves performance.