Fundamental Studies on Functionalizing Metallic Surfaces Using Femtosecond Lasers with Applications to Enhanced Heat Transfer; Novel Power
Abstract
Femtosecond laser surface processing (FLSP) of metallic surfaces is growing in popularity as a means to tailor the surface properties of metals for enhancing thermal management, altering the wetting properties, decreasing/increasing drag, anti-icing properties, altering the growth of biological agents on the surface, and changing the surface/subsurface features which alters theemissivity of the surfaces. The formation of the micron and nanoscale features along with the surface chemistry taking place is still not well understood and will be pursued at the fundamental level in this proposed research.Through major investments in infrastructure by ONR/DoD in the form of DURIP grants, UNL has developed world class facilities for understanding and advancing FLSP technology. China and Europe are also making an even larger investment in FLSP technologies. The proposed project includes the development of core technologies for the functionalization of metallic surfaces using FLSP. The core innovation of the research approach is the ability tofunctionalize surface properties (e.g., extreme wettability ranging from superhydrophobic to superhydrophilic) of a large range of practical materials including stainless steels, copper, aluminum alloys and other advanced metal alloys with microscale precision. The FLSP research effort will be focused on further developing the ability to control surface features at the micron and nanoscales; control surface chemistry, both during and after FLSP; and control subsurface grain structure and porosity in order to optimize surfaces for enhancing heat transfer. The proposed research project will have an emphasis on developing surfaces with properties that are optimized for enhanced heat transfer. The heat transfer research will be focused on developing architectures that are designed for cooling hotpots (high power laser diodes and switchingdevices) as well as thermal management of batteries used in directed energy systems. The overall goal is to remove high rates of heat (> 1 kW/cm2) from microscale hot spots or even larger hot surfaces that are encountered in many ONR and Marine Corp applications (i.e. cooling of batteries used to power directed energy systems). Efforts are intended to progress from low heatflux situations (< 100 W/cm2) towards extreme (>> 1 kW/cm2) heat fluxes. Parallel research paths are being carried out to develop capabilities for heat removal in extreme (>> 1 kW/cm2) heat flux situations: (1) flow boiling in mini- and micro-channels, carried out at UNL, and (2) heat removal by condensing water vapor on a cooled surface in a closed loop device (vapor chamber), carried out at UIC. However, due to the ability to enhance heat transfer at the interfacebetween the hot device and the cooling liquid, the enhanced heat transfer FLSP surfaces have a wide range of applications in thermal management for the Navy and Marine Corp. During the proposed project, other potential thermal management applications will be identified and pursued. Research will be conducted for fundamental understanding of the neutron voltaic power sources involving boron carbide p-i-n semiconductor radiation neutron/boron reactionsproducing alpha particles that can release free electrons in the boron carbide semiconductor p-in. In addition to being a power source, the p-i-n device is also a lightweight self-powered radiation detector, that can potentially be woven into uniforms and serve as an early warning sensor for military personnel.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 16, 2019
- Source ID
- N000142012025
Entities
People
- Craig Zuhlke
Organizations
- Office of Naval Research
- United States Navy
- University of Nebraska system