5 research outputs found
Thermal and fluid flow characteristics in a tube equipped with peripherally-cut dual twisted tapes
This article presents an experimental analysis
of the turbulent flow of water in a heat exchanger tube
fitted with peripherally-cut dual twisted tapes (PDTs) under
a constant wall heat-flux condition. The peripherallycut
dual twisted tapes with different cutting pitch ratios
(l/y = 0.5, 0.75 and 1.0) were tested for Reynolds numbers
in the range of 5400 to 14,000. The experimental results
showed thatNusselt number and friction factor of the
tubes fitted with PDTswere considerably higher than those
of the plain tube and those of the tubes with single twisted
tape (ST) and dual twisted tapes (DTs). It was found that
PDTs with l/y = 0.5, 0.75 and 1.0 gave higher heat transfer
rate than the typical DTs, with average Nusselt numbers
greater by 12.1%, 7.8% and 3.8%, respectively. For the
range investigated, PDTs with the smallest l/y ratio offered
the highest thermal performance factor of 1.14