Compound Effect of EHD Force and Micro-Structured Surface Coated With Diamond Particles

Boiling heat transfer enhancement via compound effect of the EHD effect and micro-structured surfaces has been experimentally and analytically investigated. A fluorinated dielectric liquid was selected as the working fluid. Pool boiling heat transfer in the saturated liquid was measured at atmospheric pressure. Micro-structured surfaces, which are mainly used for cutting tools, were developed with diamond particles using electro-deposition technique. Four different particle diameters were prepared: 5, 10, 15, and a mixture of 5 and 1.5 μm. The surface containing a mixture of 5 and 1.5 μm provided a 7 K reduction in the incipient superheat and a 26 % increase in the critical heat flux compared with those of a non-coated surface. Upon application of a −5 kV/mm electric filed to the micro structured surface (a mixture of 5 and 1.5 μm particles), a heat flux of 70.2 W/cm² at a superheat of 21.7K was obtained. The experimental data correlated well with previous theoretical analysis.