High-Thermal-Conductivity and High-Fluidity Heat Transfer Emulsion with 89 wt % Suspended Liquid Metal Microdroplets

Area of Science:

• Materials Science
• Fluid Dynamics
• Heat Transfer

Background:

• Colloidal suspensions with conductive particles enhance heat transfer fluids.
• High particle concentrations are limited by fluid vitrification.
• Liquid metal (LM) offers high thermal conductivity (k).

Purpose of the Study:

• To create a high thermal conductivity and high fluidity heat transfer fluid.
• To investigate eutectic Ga-In liquid metal as a soft filler in paraffin oil.
• To evaluate emulsion production methods for optimal performance.

Main Methods:

• Dispersing eutectic Ga-In liquid metal microdroplets in paraffin oil.
• Producing emulsions using probe-sonication and rotor-stator homogenization (RSH).
• Measuring thermal conductivity and viscosity at high filler loadings (up to 50 vol %).

Main Results:

• Significant thermal conductivity enhancement (Δk ~409% with probe-sonication, ~261% with RSH) at 50 vol % LM.
• Heat transport improved via high-k LM fillers above the percolation threshold.
• RSH-produced emulsion maintained high fluidity with low viscosity increase and no yield stress.

Conclusions:

• Emulsion-type heat transfer fluids with liquid metal offer superior thermal conductivity and fluidity.
• RSH method is effective for producing stable, high-performance heat transfer fluids.
• These fluids show potential for diverse thermal energy transfer applications.