Document Type : Research Paper
Authors
1 university of technology ,mechanical department, air conditioning branch
2 Mechanical Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.
Abstract
Convection heat transfer inside an empty triangular channel when filled with porous media heated proportionally with a constant heat flux (1300 W/m²) at the Reynolds number range (3165- 10910) with packed beds has been studied. The present work investigates porous media experimentally. The packed duct has a length (1 m) and (0.1 m) hydraulic diameter packed with porous material made from spherical glass particles of two different diameters (5 mm, and 10 mm). The value of porosity for the channel is (0.468,0.616 and), respectively. This research studies the effect of changing the Reynolds number and porosity on the enhanced heat transfer coefficient and local Nusselt number. The results indicated that using a porous structure enhanced the convection heat transfer coefficient significantly by (90.2%) and (92.1%) at porosity (0.616, 0.468), respectively, when compared with an empty duct. The results also revealed that the local Nusselt number decreased when the flow's axial position increased with increasing air velocity. The pressure on both ends of the test section increased as the air velocity rose and reduced as the size of the glass spheres increased. Therefore, the drag coefficient decreases as the modified Reynolds number increases with the diameter of glass spheres. The current research was compared with previous research, and the results were satisfactory. Correlational relationships were reached between the Nusselt number and the Reynolds number.
Graphical Abstract
Highlights
- Convection heat transfer is enhanced significantly in a triangular channel filled with a porous material.
- The average heat transfer coefficient increases with decreasing porosity compared to an empty triangular channel.
- The average Nusselt number decreases when using porous packed channels but increases with increasing porosity.
- Static pressure difference increases with increasing both Reynolds number and porosity.
- Empirical correlation is derived by relating the Nusselt number to the Reynolds number for the triangular porous packed channel.
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Main Subjects