  The present study reports a novel physical model for simulating Pulsating
Heat Pipes (PHP). Their high heat performance is due to the phase change over
thin liquid films. The simulation of physically correct film behavior is thus
crucial. The model adopts the one-dimensional approach, which is
computationally efficient yet still capable of capturing major physical
phenomena. The model assumes a spatially uniform film thickness, whereas both
the film thickness and length can vary over time; therefore, we call it the
oscillating film thickness model. It is based on the physical analysis of
liquid film deposition by the receding menisci of Taylor bubbles and of contact
line dynamics. Three key phenomena are addressed: (i) film deposition, (ii)
contact line receding due to dewetting acceleration by evaporation, and (iii)
mass exchange over films and contact lines. The model is evaluated by
simulating the simplest, single-branch PHP, for which detailed experimental
data are available. A quantitative agreement is reached. As the model includes
the wetting properties, their impact on oscillations is analyzed; a qualitative
agreement with the experiment is demonstrated.
