Effects of non-uniform boundary conditions on natural convection of a Herschel-Bulkley fluid

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Effects of non-uniform boundary conditions on natural convection of a Herschel-Bulkley fluid

ارائه دهنده: Provider: Amin Rezaei Mehr

اساتید راهنما: Supervisors: Mohammad Saeed Aghighi (Ph.D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Mohsen Godarzi Amireh Norbakhsh

زمان و تاریخ ارائه: Time and date of presentation: February 16, 2021 , 09:30

مکان ارائه: Place of presentation:

چکیده: Abstract: This study presents the effects of natural convection of a Herschel-Bulkley fluid numerically in a square enclosure with non-uniform boundary conditions from the bottom wall and the other cool walls. The government partial differential equations on fluid and heat transform, including continuity, momentum, and energy, are calculated by applying the Finite element method for various range of dimensionless parameters such as Rayleigh number ( ), Oldroyd number (), and different power-law range (---) in the specific number of Prandtl number (Pr = 500). Investigated on flow and heat transform parameters were the effects of non-uniform temperature distribution, Rayleigh number, Oldroyd number. The flow field and temperature inside the enclosure were analyzed using velocity vectors and temperature contours. Also, yielded and un-yielded regions in different parts of the flow domain were marked. The results show that decreasing in power-law and Oldroyd number cause the decline in the viscosity forces, leading to reducing the un-yielded regions. Nonetheless, decreasing the Rayleigh number makes convection forces weaken, thus contributing to these regions' expansion. As a result of this expansion and weakened convection forces, the velocity and Nusselt number decline. Also, two circular flow patterns are witnessed in the closure. Finally, whether the Rayleigh number decreases or the power law and Oldroyd increases, the un-yield regions expand, which causes the changes in dominant heat transfer mode from convection to conduction.

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