Studi Eksperimental Karakteristik Perpindahan Panas dan Faktor Gesekan pada Penukar Kalor Pipa Konsentrik dengan Peripherally-Cut Twisted Tape Insert with Alternate-Axis

Abstract

Abstract

Effect of peripherally-cut twisted tape insert with alternate axis (PT-A) on heat transfer, friction factor and thermal performance characteristics in the inner tube of a concentric tube heat exchanger is investigated. For comparison, the experiments using a peripherally-cut twisted tape insert (PT), a typical twisted tape insert (TT) and a plain tube are also tested in similar conditions. All twisted tape used are twisted at constant twist pitch of 50.3 mm, corresponding to a constant twist ratio of 4.0. Test runs are conducted using water as a testing fluid with Reynolds number range between 5800 and 21,500. The result show that heat transfer rate and friction factor associated by all twisted tape insert consistently higher than those plain tube. Under the similar conditions, heat transfer rate, friction factor as well as thermal performance in the inner tube fitted with PT-A are consistently higher than those in the inner tube equipped with PT, TT and also in the plain tube. Mean values of Nusselt number and friction factor given by PT-A are respectively, 94.37% and 414.2% higher than those in the plain tube, 32.40% and 119.3% higher than those in TT, and 31.95% and 80.8% higher than those in PT. In the present Reynolds number range tested, the PT-A, PT and TT offer the maximum thermal performances at constant pumping power of 1.37, 1.23 and 1.13, respectively.