Dropwise Condensation in Ambient on a Depleted Lubricant-Infused Surface

Area of Science:

• Materials Science
• Heat Transfer Engineering
• Surface Science

Background:

• Lubricant-infused surfaces (LIS) enhance dropwise condensation but suffer from lubricant depletion, reducing heat transfer efficiency.
• Non-condensable gases (NCGs) further degrade condensation heat transfer by limiting nucleation sites.

Purpose of the Study:

• To develop durable LIS using silicon porous nanochannel wicks for improved condensation heat transfer.
• To investigate the impact of lubricant viscosity and nanochannel wicks on LIS performance under NCGs.

Main Methods:

• Fabrication of fresh and lubricant-depleted LIS on silicon porous nanochannel wicks.
• Investigation of oil viscosity effects on drop mobility and condensation heat transfer.
• Long-term condensation experiments to assess durability and sustained heat transfer.

Main Results:

• Nanochannel wicks significantly improve lubricant retention, even after depletion.
• LIS with higher viscosity oil (50 cSt) on nanochannels achieved a 162% improvement in heat-transfer coefficient (HTC) over flat LIS.
• Sustained HTC of ~1.46 kW m⁻² K⁻¹ was achieved over 3 days, indicating long-term performance.

Conclusions:

• Silicon porous nanochannel wicks effectively enhance LIS durability and condensation heat transfer performance.
• The developed LIS technology offers a promising solution for efficient condensation-based systems.
• Long-term hydrophobicity and dropwise condensation are maintained, crucial for advanced heat transfer applications.