Development and evaluation of enhanced heat transfer tubes

Heat transfer enhancement has become popular recently in the development of high performance thermal systems. Enhanced surfaces are typically utilized to increase heat transfer. This study evaluated the overall thermal performance of Vipertube™ EHT, a series of enhanced tubes produced by Vipertex™. Enhancement heat transfer ratios greater than 1 were found for the four enhanced tubes that were evaluated for single phase flow in the range of Reynolds Numbers near 2900. Vipertubes enhance heat transfer through a combination of factors that include: increasing fluid turbulence, generating secondary fluid flow patterns, disturbing the boundary layer and increasing the heat transfer surface area. Additionally, the Vipertex surface design also minimizes the effects of fouling. All these factors lead to an increase in the overall heat transfer coefficient for both new designs and systems that have operated over time. Several enhanced tube configurations were studied here using heat transfer and fouling measurements. When compared to smooth tubes, the patented Vipertubes increase the overall heat transfer by more than 100% and minimized the rate of fouling. Several versions of Vipertex enhanced alloy tubes are produced under ASTM standards, thereby providing a very important advancement in heat transfer design