Thermal Management of Pulsating Heat Pipes

Pulsating heat pipes (PHPs) are passive two-phase thermal management devices comprising a capillary tube folded into multiple U-turns, which facilitate heat transport via self-sustained oscillations of liquid slugs and vapour plugs. Driven by phase change and capillary forces, PHPs offer high effective thermal conductivity and low thermal resistance, making them ideal for applications ranging from electronics cooling to waste-heat recovery, aerospace heat dissipation and cryogenic systems. The working fluid, typically a pure liquid or nanofluid, is charged at an optimal filling ratio to balance capillarity and vapour generation, while geometric parameters such as channel diameter, turn count and bend angle critically influence performance. Recent advances have focused on miniaturisation for microelectronic devices, integration of flexible substrates for wearable and deployable systems, and adaptation to extreme environments, including microgravity and ultra-low temperatures. Despite their promise, the complex interplay of multiphase flow dynamics, heat transfer and capillary action renders predictive design challenging, and standardised methodologies for characterisation remain under development.

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Thermal Management of Pulsating Heat Pipes publication trend

The graph below shows the total number of articles in thermal management of pulsating heat pipes across all publications each year (not limited to Nature Index journals).

Technical terms

Pulsating heat pipe (PHP): A capillary tube arranged in multiple U-turns that transfers heat via oscillatory two-phase flow without external pumping.

Thermal resistance: The ratio of temperature difference to heat input, indicating the opposition to heat flow within a device.

Filling ratio: The volume fraction of working fluid within the PHP, which determines the balance between liquid slugs and vapour plugs.

Capillary action: The movement of liquid within narrow channels driven by surface tension, critical for initiating oscillations in PHPs.

Nanofluid: A suspension of nanoscale particles in a base fluid, used to enhance thermal conductivity and heat transfer performance.

References

1. Advancements in pulsating heat pipes: Exploring channel geometry and characteristics for enhanced thermal performance. International Journal of Thermofluids (2024).
2. Characterization of thermal behavior of a micro pulsating heat pipe by local heat transfer investigation. International Journal of Heat and Mass Transfer (2022).
3. An Experimental Investigation of Micro Pulsating Heat Pipes. Micromachines (2014).
4. Pulsating heat pipes: Critical review on different experimental techniques. Experimental Thermal and Fluid Science (2023).
5. The Thermal—Flow Processes and Flow Pattern in a Pulsating Heat Pipe—Numerical Modelling and Experimental Validation. Energies (2021).
6. Experimental study of Large-scale cryogenic Pulsating Heat Pipe. IOP Conference Series Materials Science and Engineering (2017).
7. A Review of Working Fluids and Flow State Effects on Thermal Performance of Micro-Channel Oscillating Heat Pipe for Aerospace Heat Dissipation. Aerospace (2023).
8. Performance of flat-plate, flexible polymeric pulsating heat pipes at different bending angles. Applied Thermal Engineering (2022).