Simulation and Experimental Study of Pulsating Heat Pipe Performance Using CASCO Code
Researchers have used version 4 of the CASCO simulation software to study two key phenomena in pulsating heat pipes (PHPs): the effect of surface properties on bubble nucleation and the stopover regime. Experimental validation was conducted against two different PHP prototypes, including the PHP Smart Loop. The findings identify an optimal nucleation barrier value that minimizes thermal resistance and explain how higher heating loads reduce stopover time, improving heat pipe performance.
The study, submitted to arXiv and presented at the Joint 23rd IHPC and 17th IHPS conference in Gdańsk, Poland (May 2026), investigates the steady-state functioning of pulsating heat pipes using the CASCO simulation code. Two phenomena are examined: the nucleation barrier — the wall superheating required for bubble formation, which reflects wall wettability and roughness — and the stopover regime, in which oscillations temporarily cease. Experiments with the first prototype show that an optimal nucleation barrier exists at which thermal resistance reaches a minimum for a given evaporator power, with continuous pressure waves propagating throughout the PHP channel. The second prototype, the PHP Smart Loop, reveals that the stopover regime consists of a chaotically repeating sequence of rapid pressure growth during oscillations followed by slower pressure decay during stopovers. Higher heating loads are found to shorten stopover duration by accelerating liquid film shrinking, which accounts for the observed decrease in thermal resistance with increasing power input.
What's missing
The chaotic nature of the stopover regime is noted but no quantitative predictive model for stopover duration is presented. Long-term reliability and scalability of the CASCO v4 predictions to larger or differently configured PHP systems remain open questions.
What different sources said
- arXiv physicsCenter
Studies of PHP with CASCO code and its experimental validation
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