A numerical study of transient natural convection of water near its density extremum

This numerical (CFD) study investigates the transient natural convection of water near its density extremum in enclosed spaces. Two cases are considered: flows in rectangular cavities; flows within a vertical cylindrical geometry. A non-Boussinesq approach is employed for both cases and the results...

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Main Author: Othman, Safiah
Format: Thesis
Language:en
Published: 2005
Subjects:
Online Access:http://eprints.uthm.edu.my/2780/1/SAFIAH%20OTHMAN%20-%2024p.pdf
http://eprints.uthm.edu.my/2780/
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author Othman, Safiah
author_facet Othman, Safiah
author_sort Othman, Safiah
building UTHM Library
collection Institutional Repository
content_provider Universiti Tun Hussein Onn Malaysia
content_source UTHM Institutional Repository
continent Asia
country Malaysia
description This numerical (CFD) study investigates the transient natural convection of water near its density extremum in enclosed spaces. Two cases are considered: flows in rectangular cavities; flows within a vertical cylindrical geometry. A non-Boussinesq approach is employed for both cases and the results are compared to previous studies. For the first case of rectangular cell, the cavity was not filled completely full of water, and a small gap is left at the top in order to have a free surface. Simulations are carried out with water having initial temperatures of 8, 12, 16 and 20 °C, which is equal to temperature of the opposing walls, while the entire cavity is insulated. The fluid is initially still and the temperature of one vertical wall is suddenly lowered to 0 °C. Measurements of the temperature distributions in the cavity were made at three different vertical positions: yl = 0.01785 m,y2 = 0.07545 m andy3 = 0.1353 m. Comparison of both predicted flow patterns and calculated temperatures to the previous study are presented, which confirms that good agreements are obtained. For the second case of vertical cylinder, distilled water having initial temperature of 8 °C is used as the medium, while the entire cavity is insulated. This experimental chamber is enclosed within another glass cylinder, and coolant fluid at a fixed temperature of 0 °C is pumped continuously through the annular region between the cylinders. The comparisons of cooling curves with previous work are made at three different vertical heights of 32, 64 and 96 mm. Results of cooling curve measurements and the flow patterns present good agreement. From the resulting numerical output of both cases, it is evident that the density inversion of water has a significant influence on the natural convection in the cavity
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spelling my.uthm.eprints-27802022-02-03T01:52:14Z http://eprints.uthm.edu.my/2780/ A numerical study of transient natural convection of water near its density extremum Othman, Safiah TA349-359 Mechanics of engineering. Applied mechanics This numerical (CFD) study investigates the transient natural convection of water near its density extremum in enclosed spaces. Two cases are considered: flows in rectangular cavities; flows within a vertical cylindrical geometry. A non-Boussinesq approach is employed for both cases and the results are compared to previous studies. For the first case of rectangular cell, the cavity was not filled completely full of water, and a small gap is left at the top in order to have a free surface. Simulations are carried out with water having initial temperatures of 8, 12, 16 and 20 °C, which is equal to temperature of the opposing walls, while the entire cavity is insulated. The fluid is initially still and the temperature of one vertical wall is suddenly lowered to 0 °C. Measurements of the temperature distributions in the cavity were made at three different vertical positions: yl = 0.01785 m,y2 = 0.07545 m andy3 = 0.1353 m. Comparison of both predicted flow patterns and calculated temperatures to the previous study are presented, which confirms that good agreements are obtained. For the second case of vertical cylinder, distilled water having initial temperature of 8 °C is used as the medium, while the entire cavity is insulated. This experimental chamber is enclosed within another glass cylinder, and coolant fluid at a fixed temperature of 0 °C is pumped continuously through the annular region between the cylinders. The comparisons of cooling curves with previous work are made at three different vertical heights of 32, 64 and 96 mm. Results of cooling curve measurements and the flow patterns present good agreement. From the resulting numerical output of both cases, it is evident that the density inversion of water has a significant influence on the natural convection in the cavity 2005 Thesis NonPeerReviewed text en http://eprints.uthm.edu.my/2780/1/SAFIAH%20OTHMAN%20-%2024p.pdf Othman, Safiah (2005) A numerical study of transient natural convection of water near its density extremum. Masters thesis, Universiti Tun Hussein Onn Malaysia.
spellingShingle TA349-359 Mechanics of engineering. Applied mechanics
Othman, Safiah
A numerical study of transient natural convection of water near its density extremum
title A numerical study of transient natural convection of water near its density extremum
title_full A numerical study of transient natural convection of water near its density extremum
title_fullStr A numerical study of transient natural convection of water near its density extremum
title_full_unstemmed A numerical study of transient natural convection of water near its density extremum
title_short A numerical study of transient natural convection of water near its density extremum
title_sort numerical study of transient natural convection of water near its density extremum
topic TA349-359 Mechanics of engineering. Applied mechanics
url http://eprints.uthm.edu.my/2780/1/SAFIAH%20OTHMAN%20-%2024p.pdf
http://eprints.uthm.edu.my/2780/
url_provider http://eprints.uthm.edu.my/