Enhancement of Heat Transfer in the Bundles of Transversely-Finned Tubes

An asymptotic approach to generalizing the experimental data on convective heat transfer of tube bundles in crossflow

“…The presence of maximum heat transfer and its shift with variation in the finning coefficient are well explained by the flow and local heat transfer results [17][18][19] obtained using the above-mentioned generalized hydrodynamic concepts -by the degree of flow constriction and the level of flow disturbance deep in the bundle. Most of the influence of each of these factors as a whole determining heat transfer enhancement at Re = const is consistent with different values of the generalized parameter r 1 /r 2 .…”

“…The analysis of the above data and the flow and local heat results [17][18][19][20] enables one to explain how the value of the exponent m depends on the tube arrangement parameter r 1 /r 2 . As already mentioned, the disturbance level of the flow around deep-laid rows to a considerable extent depends on the tube arrangement geometry.…”

“…-The behavior of heat transfer in transversely finned tube bundles is mainly determined by secondary three-dimensional separated flows that develop in the field of contact of a fin and a tube due to the boundary layers being formed at the fin surfaces [17,18]. -The interaction of these separated flows with shear layers, which have separated from the surfaces with tube finning, results in developing complex three-dimensional vortex structures in the wake (Fig.…”

“…At the same time, the investigations of the mechanisms of flow [17] and local heat transfer [18] at the finned tube surface and also of the flow behavior in bundles as a whole for different versions of tube arrangement [19] were made at NTUU ''KPI''. As a result, new data on the nature of transfer processes in interfin and intertube spaces were obtained and generalized in the form of the physical model for flow and heat transfer at the transversely finned tube surface [20].…”

Heat Analysis and Thermodynamic Effects

“…The bent tube segments in this case press the flow toward the trailing part of the finned tube, thus directing highly-intense secondary flows that are generated in the root region of the leading part of the tube (Pis'mennyi, 1984;Pis'mennyi & Terekh, 1993b) deeper into the space downstream of the tube. This, in the final analysis, decreases markedly the size of the trailing vertical zone, which is clearly seen by comparing Figs.…”