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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL STUDY ON MULTI-SCALE HEAT TRANSFER IN ANNULUS HEATED BY NON-UNIFORM HEAT FLUX

Get access (open in a dialog) DOI: 10.1615/IHTC16.ctm.023115
pages 3937-3945

Abstract

The characteristics of rarefied and continuum gaseous heat transfer under non-uniform heat flux condition in the annulus of parabolic trough solar collector are simulated by direct simulation Monte Carlo (DSMC) method and finite volume method (FVM), respectively. Firstly, the effect of gas pressure in the annulus on heat transfer performance under non-uniform and uniform heat flux conditions are investigated and compared. Then, the influence of solar elevation angle φ on the fluid flow and heat transfer in the annulus is also studied. Finally, the effect of heat flux density on gaseous heat transfer is further analyzed. Results show that the gas flow and heat transfer are affected remarkably by the pressure and thermal boundary conditions. The gaseous heat transfer capability increases with the increase of pressure in the annulus. Besides, the gaseous heat transfer capability at atmosphere pressure is about 100 times stronger than it is at 0.01 Pa. There are remarkable differences of gas flow and heat transfer when the solar elevation angle φ changes at high pressure in the annulus. However, the solar elevation angle φ has a slight influence on the gaseous heat transfer at low pressure. With the increase of heat flux density, the gaseous heat transfer capability increases in the annulus at atmosphere pressure because of stronger natural convection.