Shaping Metallic Surfaces Using Femtosecond Laser Pulses for Thermal System Management and Other Applications
Abstract
This project builds on the research conducted for the Office of Naval Research (ONR) through previous contracts and grants, the most recent being N00014-20-1-2025. This proposal is in pursuant of the $3.25 M line item titled #Shaping metallic surfaces for thermalsystem management# in H.R. 2882, the Further Consolidated Appropriations Act of 2024. The long-term goal of the ongoing ONR programis to enable a transformation in materials available to DoD with advanced functional properties that are suitable for applications in harsh environments through the decoupling of surface and bulk properties. The enabling technology to achieve this goal being developed by the Center for Electro-optics and Functionalized Surfaces (CEFS) is femtosecond laser surface processing (FLSP), where femtosecond pulses are used to directly modify the surface of materials, thereby altering surface properties without the use of paints or coatings. The proposed project has two goals. The first is to address issues with scaling FLSP to large areas needed for many Navyand DoD applications. The second is to develop facilities and techniques to study the application of the FLSP surfaces in enhancingheat transfer, especially for cooling of high-power laser diodes. Specifically, the interest in this research is the removal of heat from extreme heat-flux applications using boiling with dielectric fluids/refrigerants at high pressure.FLSP is growing in popularity as a means to tailor the surface properties of materials for many applications including enhancing heat transfer for thermal management, altering wetting properties, decreasing/increasing drag, as well as creating anti-icing, anti-microbial, and broadband absorbing/high emissivity surfaces. Through major investments in infrastructure by ONR/DoD in the form of DURIP grants, the University ofNebraska-Lincoln (UNL) has developed world class facilities for understanding and advancing FLSP. The proposed project includes thedevelopment of coretechnologies for the functionalization of large area metallic surfaces, targeting areas up to 1 m x 2 m using FLSP and surfaces for thermal management of high-power density optical and electronic devices. The core innovation of the research approach is the ability to functionalize surfaces (e.g., create extreme wettability ranging from superhydrophobic to superhydrophilic) of a large range of practical materials including stainless steels, copper, aluminum, metal alloys, and ceramics with microscale precision. The FLSP research effort will be focused on further developing the ability to control surface features at the micro- and nano-scales; control surface chemistry, both during and after FLSP; and control subsurface grain structure and porosity with large-areauniform processing and to optimize surfaces for enhanced heat transfer.The focus of this research, which relies on the 2022 DURIP-funded high-power laser at UNL, will enable basic research to fully utilize this laser technology for scaling processing to large areas required for many applications by upgrading facilities at UNL with a large-scale CNC system targeting 1 m x 2 m with micron levelprecision. The proposed research project will also have an emphasis on developing metal surfaces with properties that are optimizedfor enhanced heat transfer. The heat transfer research will be focused on developing architectures that are designed for cooling high power laser diodes by upgrading heat transfer facilities to work with dielectric refrigerants at high pressure in pool boiling and flow boiling in FLSP-functionalized mini- and micro-channels. The overall goal is to remove high rates of heat (> 1 kW/cm^2) from microscale hot spots or even larger hot surfaces that are encountered in many ONR and Marine Corps applications. Efforts are intended to progress from low heat flux situations (< 300 W/cm^2) towards extreme (> 1 kW/cm^2) heat fluxes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 09, 2024
- Source ID
- N000142412738
Entities
People
- Craig Zuhlke
Organizations
- Office of Naval Research
- United States Navy
- University of Nebraska system