Electrospun Superhydrophobic Silica Nanofiber Coatings for Enhanced Pool Boiling on Copper Foam.

Superhydrophobic SiO2 nanofibers were deposited on copper foam substrates via micro/nano surface modification to improve the pool boiling heat transfer performance of porous copper media. By adopting an electrospinning technique, uniform and robust superhydrophobic SiO2 nanofibers were firmly deposited on copper foam skeletons, forming interconnected porous structures with intrinsic superhydrophobic characteristics. The fabricated superhydrophobic nanofiber structures greatly reduce bubble nucleation resistance and provide sufficient stable vaporization sites, effectively promoting boiling heat transfer enhancement. Experimental results verify that surface modification with superhydrophobic SiO2 nanofibers significantly improves the overall boiling performance of copper foam. The sample with a nanofiber loading of 1.8 mg achieves the optimal thermal performance, presenting lower wall superheat, higher critical heat flux, and an improved heat transfer coefficient. CFD simulations were conducted, and the numerical results exhibit good consistency with experimental measurements.