Radiative heat transfer in a flowing gas-particle mixture
A gaseous suspension of small particles is considered as a medium to directly absorb concentrated sunlight to yield a high-temperature gas for electricity production or industrial processes. A receiver employing a directly irradiated gas-particle mixture has several advantages over conventional blackened tube solar receivers. The primary benefit is the much improved heat transfer between the incident radiation and the gas. The more effective heat transfer results in lower receiver wall temperatures, and permits high incident fluxes allowing smaller, more efficient receivers. This work examines the optical characteristics of a carbon-particle mixture, and the ensuring temperature profiles when the flowing mixtures is radiantly heated. Single-particle absorption and scattering efficiencies and phase functions are calculated from Mie theory for different particle sizes and carbon indices of refraction. Experimental measurements of the extinction coefficient at 0.633 {mu}m and the phase function at 0.442 {mu}m of a carbon particle aerosol, along with a determination of the particle size distribution, showed somewhat less scattering and more absorption than was calculated. A four-flux radiative transfer model was developed and solved simultaneously with the energy equation.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 7051556
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140700* -- Solar Thermal Power Systems
141000 -- Solar Collectors & Concentrators
AEROSOLS
CARBON
COLLOIDS
DISPERSIONS
ELEMENTS
ENERGY TRANSFER
EQUIPMENT
FLUIDS
GASES
HEAT TRANSFER
MATHEMATICAL MODELS
MIXTURES
NONMETALS
PARTICLE SIZE
PARTICLES
SCATTERING
SIZE
SOLAR ABSORBERS
SOLAR EQUIPMENT
SOLAR RECEIVERS
SOLS