Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7045821 | Applied Thermal Engineering | 2018 | 36 Pages |
Abstract
The circular and rectangular helical-coils were sited in elliptic tube section with four various pitches of 20, 45, 135 and 225â¯mm. The cold air Re number was ranged from (11â¯Ãâ¯103â¯â¤â¯Reâ¯â¤â¯3.375â¯Ãâ¯104). The effect of reverse-flow for different pitches and inserted helical wire cross-sections can improve the heat transfer rate. Also, comparing with previous studies, the use of circular and rectangular wire cross-sections inserted in elliptic tube at various helical-coil pitches was useful over the smooth tube, and rectangular cross-section helical-coil is more potent in heat transfer enhancement rather than circular one. Nu, f and η for rectangular helical wire cross-section inserted in elliptic tube are higher than that is for circular one for all values of helical-coil pitches by about 15%, 3% and 14% respectively. η for the current elliptic tube fixed with circular and rectangular helical-coil are higher than that of Sharafeldeen et al. (2017) for all helical-coil pitches by about 24.5% in average. Correlated data results of Nu, f and η for helical-coil with different wire cross-sections are obtained for the considered Re range.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
M.A. Omara, Mohamed A. Abdelatief,