Permittivity Gradients, Polarization, and Gas Dynamics in Composite Electromagnetic Heat Exchangers
Abstract
A research program into the fundamental heat-transfer processes for beamed-energy harnessingapplications is proposed. Of interest is to quantify the conversion efficiency of incoming electromagnetic radiation into elevated internal energy of a compressible coolant. The idea is to useelectromagnetic-radiation absorbing materials, either porous or designed with channels throughwhich a coolant can flow, that can withstand temperature up to 2000K, heat these materialsthrough the application of electromagnetic waves, and then run coolant through the material toharness the desired energy. Since electrical conductivity of these materials depends on temperature, multiple steady temperatures are possible at the same input power. The research program centers on using asymptotic multiscale methods including homogenization to formulate an effective medium theory to describe the energy conservation and electric field propagation through this medium, for incompressible and compressible coolants. The spatial variation of loss factor willbe examined in order to compensate for conduction losses found at higher temperatures, and as asimple model for metal-ceramic composites. These results depend on the examination of the energy transfer between the composite and the coolant, and we shall consider these modes for incompressible and compressible coolants. Three-dimensional electric field amplitude equations, developed in our current award AFOSR FA9550-15-0476 using high-frequency homogenization, will be extended to incorporate heat transfer, viscous fluid flow spatial dimensions, and comparisons with solutions using finite-difference time-domain and with finite-element methods will be performed. The goal is to develop a systematic method to better understand wave propagation, heat transfer and power delivery to the coolant for a general three-dimensional spatially-periodic microstructure.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 24, 2019
- Source ID
- FA95501810528
Entities
People
- Burt Tilley
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- Worcester Polytechnic Institute