Heat transfer and flow behaviors in three-dimensional circular tubes with loose-fit multiple channel twisted tapes were numerically studied. The investigation was examined for Reynolds numbers （Re） ranging from 5000...Heat transfer and flow behaviors in three-dimensional circular tubes with loose-fit multiple channel twisted tapes were numerically studied. The investigation was examined for Reynolds numbers （Re） ranging from 5000 to 15,000, by using air as testing fluid. Effects of the multiple channel number （N = 2, 3, and 4）, clearance ratio （CR = 0.0, 0.025, 0.05, and 0.075） on heat transfer enhancement and flow friction were examined. The numerical results indicate that the tubes with loose-fit multiple channel twisted tapes perform higher heat transfer rates than the plain tube. The enhanced heat transfer rate is escorted with larger pressure drop. Both heat transfer and pressure drop increase with increasing multiple channel number （N） and decreasing clearance ratio （CR）. Heat transfer augmented by the loose-fit multiple channel twisted tape with N = 4 is higher than those enhanced by the ones with N = 2 and 3 by around 9.5-17.8% and 5.8-7.8%, respectively. In addition, the loose-fit multiple channel twisted tapes with clearance ratio of 0.025, 0.05, and 0.075 give lower heat transfer rates than the one with CR = 0.0 by around 8.4%, 17.5%, and 28.8%, respectively.展开更多
This research explores the opportunities offered for the creation of a green city on the recently secured Bagmati riverbanks in Kathmandu,which is subject to rapid inward migration from landless rural farmers.The rese...This research explores the opportunities offered for the creation of a green city on the recently secured Bagmati riverbanks in Kathmandu,which is subject to rapid inward migration from landless rural farmers.The research asks what architectural theory and practice can contribute to this setting to support the fit between emergent bottom-up initiatives and topdown city investments.To this end,it deepens and extends loose fit theory,research methods,and reflective practices to investigate latent possibilities,assemble a narrative of embedded change,and create spatial imaginaries of topographical change on the Bagmati riverbanks.Moreover,it argues that architectural theory and practice can play a vital role in integrating migrants into civic institutions and helping generate a highly green city by making the relation-ships between setting and occupant explicit,stimulating and representing alternative imaginaries,and framing a civic discourse.展开更多
文摘Heat transfer and flow behaviors in three-dimensional circular tubes with loose-fit multiple channel twisted tapes were numerically studied. The investigation was examined for Reynolds numbers （Re） ranging from 5000 to 15,000, by using air as testing fluid. Effects of the multiple channel number （N = 2, 3, and 4）, clearance ratio （CR = 0.0, 0.025, 0.05, and 0.075） on heat transfer enhancement and flow friction were examined. The numerical results indicate that the tubes with loose-fit multiple channel twisted tapes perform higher heat transfer rates than the plain tube. The enhanced heat transfer rate is escorted with larger pressure drop. Both heat transfer and pressure drop increase with increasing multiple channel number （N） and decreasing clearance ratio （CR）. Heat transfer augmented by the loose-fit multiple channel twisted tape with N = 4 is higher than those enhanced by the ones with N = 2 and 3 by around 9.5-17.8% and 5.8-7.8%, respectively. In addition, the loose-fit multiple channel twisted tapes with clearance ratio of 0.025, 0.05, and 0.075 give lower heat transfer rates than the one with CR = 0.0 by around 8.4%, 17.5%, and 28.8%, respectively.
基金The authors would like to thank all the students who took part in thc work in Ncpal during thc ycars 20142017,and particularly to Jake Winter and Jack Tiong whose work is reproduced here.They would also like to thank Dr Bo Tang and Robert Barnes who also took part and facilitated much of the work which made the writing of this paper possible.
文摘This research explores the opportunities offered for the creation of a green city on the recently secured Bagmati riverbanks in Kathmandu,which is subject to rapid inward migration from landless rural farmers.The research asks what architectural theory and practice can contribute to this setting to support the fit between emergent bottom-up initiatives and topdown city investments.To this end,it deepens and extends loose fit theory,research methods,and reflective practices to investigate latent possibilities,assemble a narrative of embedded change,and create spatial imaginaries of topographical change on the Bagmati riverbanks.Moreover,it argues that architectural theory and practice can play a vital role in integrating migrants into civic institutions and helping generate a highly green city by making the relation-ships between setting and occupant explicit,stimulating and representing alternative imaginaries,and framing a civic discourse.
