Radiation Barrier Coatings: Probing the fundamental conductive and radiative heat transport processes of high temperature coatings with ultrafast laser probes
Abstract
The fundamental thermal transport processes that contribute to heat transfer in intensely heated coatings that operate at temperatures above 1000 C are driven by carrier and phonon conduction processes along with radiative thermal transport. An ideal protective coating would thus possess ultralow thermal conductivity by maximizing phonon scattering processes while blocking heat carrying blackbody radiation by appearing IR opaque in the window of peak blackbody emission around > 1000 C (e.g., opaque to wavelengths < 2200nm). The overarching objective of this proposed work is to develop novel laser-based metrologies to measure the thermal conductivity and radiative heat transport of novel coatings designed to provide superior thermal insulation to both radiation and conduction thermal transport. These Radiation Barrier Coatings, which will be developed in close collaboration with Professor David Clarke (Harvard), Professor Prasanna Balachandran (UVA) and Professor Haydn Wadley (UVA), will be designed for use and integration into high temperature engine environments, and thus have additional physical property characteristics that will ensure the survivability of these materials in the harsh atmospheres of jet turbine engines. Our proposed work will develop the capability to measure the blackbody absorption/emissivity, radiative thermal transport, and phonon thermal conductivity of novel high temperature coatings that are designed with specific dopants and inclusions to block radiative heat transfer and minimize thermal conduction. A key advance in theexperimental development proposed here is the ability to time resolve the mechanisms of photon, electron and phonon coupling processes esses that drive radiation emission and resulting thermal transport, and phonon conduction in novel high temperature coatings. The experimental measurements in this work will be guided by collaborative efforts focusing on theoretical calculations and computational simulations that will guide the development of novel high temperature coatings. These radiation barrier coatings will be developed based on the experimental measurements and computational predictions on various silicates and zirconates with rare earth and/or transition metal ions used to obtain desirable thermal, mechanical the chemical properties in typical jet engine environments. We will work closely in collaboration with Clarke (Harvard, collaboration lead), Wadley (UVA), and Balachandran (UVA) to use computationalmaterials design, first principles simulations and atomistic modeling to guide the development of the novel radiation blocking thermal/environmental barrier coatings and design the experiments that will be built to probe the radiation and phonon thermal transport. A constant feedback loop between experimental measurements, experimental development and coating design and fabrication will be enabled through theory and computation from first principles atomistic to continuum scales. The proposed effort to measure and optimize the conduction and radiation thermal transport in high temperature coatings is directly relevant to Navy propulsion needs for reliably and performance of thermal/environmental barrier coatings in hot section components of turbine engines. The coating used in gas turbine engines are utilized by the Navy for both its aircraft and ship propulsion platforms. These coatings ensure high temperature operation, thus improving engine efficiency leading to lower fuel burn and reducing costs, and our novel radiation barrier coatings will provide a disruptive solution to improve efficiency in turbine engines for the Navy.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2021
- Source ID
- N000142112477
Entities
People
- Patrick Hopkins
Organizations
- Office of Naval Research
- United States Navy
- University of Virginia