Enhanced pool-boiling heat transfer and critical heat flux on femtosecond laser processed stainless steel surfaces

Authors

Cory M. Kruse, University of Nebraska-LincolnFollow
Troy Anderson, University of Nebraska-Lincoln
Chris Wilson, University of Nebraska-Lincoln
Craig Zuhlke, University of Nebraska-LincolnFollow
Dennis Alexander, University of Nebraska-LincolnFollow
George Gogos, University of Nebraska-LincolnFollow
Sidy Ndao, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2015

Citation

Int J Heat Mass Transf. 2015 March ; 82: 109–116.

Comments

Kruse et al.

Public access

doi:10.1016/j.ijheatmasstransfer.2014.11.023

Abstract

In this paper, we present an experimental investigation of pool boiling heat transfer on multiscale (micro/nano) functionalized metallic surfaces. Heat transfer enhancement in metallic surfaces is very important for large scale high heat flux applications like in the nuclear power industry. The multiscale structures were fabricated via a femtosecond laser surface process (FLSP) technique, which forms self-organized mound-like microstructures covered by layers of nanoparticles. Using a pool boiling experimental setup with deionized water as the working fluid, both the heat transfer coefficients and critical heat flux were investigated. A polished reference sample was found to have a critical heat flux of 91 W/cm² at 40 °C of superheat and a maximum heat transfer coefficient of 23,000 W/m² K. The processed samples were found to have a maximum critical heat flux of 142 W/cm² at 29 °C and a maximum heat transfer coefficient of 67,400 W/m² K. It was found that the enhancement of the critical heat flux was directly related to the wetting and wicking ability of the surface which acts to replenish the evaporating liquid and delay critical heat flux. The heat transfer coefficients were also found to increase when the surface area ratio was increased as well as the microstructure peak-to-valley height. Enhanced nucleate boiling is the main heat transfer mechanism, and is attributed to an increase in surface area and nucleation site density.