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Numerical Investigation of Air-Side Heat Transfer and Pressure Drop in Circular Finned-Tube Heat Exchangers
| Content Provider | Semantic Scholar |
|---|---|
| Author | Mon, Mi Sandar |
| Copyright Year | 2003 |
| Abstract | Numerical Investigation of Air-Side Heat Transfer and Pressure Drop in Circular Finned-Tube Heat Exchangers The present numerical study has been carried out to investigate the temperature and velocity profiles in banks with circular finned-tubes in cross flow. The purpose of this investigation is to develop satisfactory correlations and concurrently providing complements to the local convective characteristics. The coolant passes through the tubes, which are maintained at a constant temperature and the dry air is used as the convective heat transfer medium. To demonstrate the influence of the geometric parameters, numerical investigations are carried out for different finning geometries and number of rows. In addition, attempts are made to validate which tube configuration is more constructive. A large computational effort is involved for the memory access of the computers and computing time for the simulation of the complex geometries associated with the dense grids. The available computational fluid dynamics software package FLUENT is applied to determine the related problems. Renormalization group theory (RNG) based k ε turbulence model is allowed to predict the unsteady three-dimensional flow and the conjugate heat transfer characteristics. The numerical flow visualization results reveal the important aspects of the local heat transfer and flow features of the circular finned-tube bundles. These include boundary layer developments between the fins, the formation of the horseshoe vortex system, the local variations of the velocity and temperature on the fin geometries and within the bundles. The boundary layers developments and horseshoe vortices between the adjacent fins and tube surface are found to be dependent substantially on the fin spacing and Reynolds number. The local temperature distributions over the fin surface vary both circumferentially and radially, and there is no significant difference over the fin surface and in the middle of the fin for both tube arrays. To determine the optimum dimension of the geometries, comparisons are prepared in terms of the bundle performance parameter. These data indicate that for the benefit of pumping power, the in-line array has a better performance than the staggered arrangement at low Reynolds number. However, the margin between the inline and staggered arrays becomes narrower when the Reynolds number is increased. The average heat transfer and pressure drop results for both tube configurations are presented. All proposed correlations, based on the numerical and relevant experimental data, are recommended for a wide range of Reynolds numbers (based on the air velocity through the minimum free flow area and the tube outside diameter) from 5 x 10 to 7 x 10. The heat transfer and pressure drop results agree well with several existing experimental correlations. The present numerical investigations suggest a good estimate of the Nusselt number and Euler number for circular finned-tube heat exchangers. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.qucosa.de/fileadmin/data/qucosa/documents/2029/dissmon.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
