Abstract: Developed from the solid spiral-finned-tube, the serrated spiral-finned-tube has wide application prospects in large-scale heat-exchange facility due to its advantages such as easy manufacture, high fin ratio，high heat transfer coefficient and fin efficiency. In order to get known the effects of tube layout structures on heat transfer and flow resistance characteristics of serrated spiral-finned-tube banks (SSB), nine SSB with staggered layouts in terms of various transverse pitch (S1) and longitudinal pitch (S2) of tube banks are tested after an analysis of its influencing mechanism. Accordingly, the effects of S2 on heat transfer and flow resistance characteristics of SSB are obtained, and the corresponding correlations are put forward. The experimental results show that with the same Re number of fin-side and relative transverse pitch (S1/do), the Eu number decrease with the increasing of S2, while there is an optimum relative longitudinal pitch (S2/do) to make Nu number and comprehensive heat transfer performance index j/f (ratio of Colburn heat transfer factor and friction factor) of fin-side reach a maximum associated with a certain S1/do; on the premise of same Re number and S1/do, the appropriate selection of S2/do can make Nu number increase about 6% and Eu number decreases slightly in the test range of S2/do= 2.41～3.07, and the j/f index can increase about 7%.

Key words: Flow resistance characteristic, Heat transfer characteristic, Heat transfer enhancement, HRSG, Serrated spiral-finned-tube