Investigation of Dean number and curvature ratio in a double-pipe helical heat exchanger

A double-pipe helical heat exchanger was numerically studied to determine the effects of Dean number and curvature ratio on heat transfer and pressure drop characteristics for laminar flow. Used model in this paper is helical copper tubes. The results were compared to the values existed in open literature and areasonable agreement was observed. It was found that the overall heat transfer coefficient increases by increasing the inner and annulus Dean numbers. Also, it can be mentioned that for a given annulus Dean number, increasing the inner Dean number results in an eventual asymptotic overall heat transfer coefficient. The results showed that the high Dean number causes high pressure drop. Also, mathematical models for both overall heat transfer coefficient and inner pressure drop was represented. On the curvature ratio, it can be stated that increasing this parameter enhances the overall heat transfer coefficient and causes low pressure drop.

کلیدواژه ها:

Double-pipe helical heat exchanger ، Dean number ، Curvature ratio