Enhanced spray cooling on patterned perforated micromesh surface

The increasing power density in applications such as aerospace, nuclear power, laser weapons, and phased array radar has led to a growing demand for efficient thermal management technologies. Spray cooling, known for its high heat flux dissipation and excellent temperature uniformity, has garnered great interest. Micro/nano-structured surfaces have been adopted to enhance spray cooling, especially in the phase-change heat transfer regime. However, manipulating bubble dynamics for non-interfering liquid and vapor flow paths remains a challenge under high heat flux conditions. This work employs a cost-effective laser drilling technique to fabricate patterned multilayer perforated copper micromesh surfaces to enhance spray cooling. By creating separated liquid-vapor flow paths, bubble escape resistance is reduced, and the formation of vapor blankets within the perforated micromesh stack is delayed. Increasing the diameter and decreasing the separation between the perforations can strengthen the liquid and vapor transport, while reducing the liquid film boiling area. An analysis of flow resistance along bubble escape paths, caused by the anisotropic permeability of the multilayer micromesh in different directions, is performed to optimize the design of perforated microporous structures. A critical heat flux (CHF) of 1213 W/cm2, with a heat transfer coefficient (HTC) of 352.6 kW/(m2 K), is achieved on the patterned perforated micromesh surface, which is an improvement of 115% and 142%, respectively, compared to the plain surface.