Experimental Investigation of Liquid Metal Droplet on the Heat Transfer Performance in an Oscillating Heat Pipe

An oscillating heat pipe (OHP) charged with a hybrid fluid is investigated. This hybrid fluid uses an emulsion-based mixture of liquid metal gallium microdroplets suspended in an ethanol solution. The gallium microdroplets are fabricated using an ultrasonication technique. The OHP is fabricated from a copper plate and contains a six-turn channel with a 3 × 3 mm² cross section. The heat transfer performance of the OHP was investigated experimentally with different concentrations of gallium at a 50% filling ratio. Steady-state oscillating motion was achieved with weight concentrations of gallium up to 20%. The experimental results show that using gallium-in-ethanol hybrid fluid emulsion as the working fluid can increase the heat transfer performance of the OHP by up to 7.8% over pure ethanol at 300 W. The mass of gallium needed to achieve this magnitude of heat transfer improvement is drastically reduced compared to previous research.