Optimal Design of Fluid Flow and Heat Transfer in Pipe Jackets Having Bow Cross-Sections

Pipe jackets are widely used in engineering as a component for heating or cooling reactors or other equipment. In this paper, fluid flow and heat transfer performances in straight or helical pipes having bow cross-sections with the central angle α in the range of 90–180° were numerically simulated using water as the medium under turbulent flow conditions. The results show that, under the same volume flow rate, the bow cross-sectional pipe with α less than 180° can enhance heat transfer and shows better comprehensive heat transfer performance compared with the half-pipe with α being 180°. As a result, less heat exchange surface (or the weight) of the bow cross-sectional pipe is needed for transferring the same amount of heat. Specifically, for the helical pipe having the bow cross-section with α being 90°, the weight of the pipe can be reduced by about 80%. In order to facilitate the engineering design of bow cross-sectional pipe jackets, correlation formulas for Nu and f of the whole straight pipe and the helical pipe were modified to include the influence of the central angle α of the bow cross-sections.