Title:
Spectral radiative properties and radiation heat transfer of bauxite and SiO2 particles for solar thermal applications
Spectral radiative properties and radiation heat transfer of bauxite and SiO2 particles for solar thermal applications
Author(s)
Chen, Chuyang
Advisor(s)
Zhang, Zhuomin
Loutzenhiser, Peter G.
Loutzenhiser, Peter G.
Editor(s)
Collections
Supplementary to
Permanent Link
Abstract
The use of bauxite- and silica-based ceramic particles as solar thermal energy storage materials in concentrated solar power (CSP) plants enables dispatchable grid-scale electricity generation. The solar-to-thermal conversion efficiency is sensitive to both the radiative properties of the particles and the pertinent radiative heat transfer processes. This thesis addresses relevant knowledge gaps to more accurately characterize and radiative properties of particle beds over a wide range of temperatures. The radiative properties of bauxite particles are studied by measuring and modeling the spectral absorptance. Using the effective medium approach, the optical constants are modeled and used to calculate the theoretical absorptance. A high-temperature emissometer is developed to measure the temperature-dependent emittance of bauxite and silica particle beds. The temperature-dependent infrared phonon modes are characterized by fitting the results with a Lorentz oscillator model. Polydisperse silica particles of different types and sizes are measured for reflectance and transmittance. The effective absorption and scattering coefficients are retrieved from measurements and compared with prediction by independent scattering theory to study the effect of dependent scattering. From a geometric optics standpoint, a discrete scale Monte Carlo ray tracing algorithm is developed to simulate the radiative properties of particle beds numerically. The effects of particle volume fraction, particle mixing, and refractive index on radiative properties are analyzed. The findings from this thesis lead to improved estimations of radiative heat transfer in particulate media and designs of particle-based concentrating solar thermal technologies.
Sponsor
Date Issued
2022-04-28
Extent
Resource Type
Text
Resource Subtype
Dissertation