Abstract: Experimental studies, establishing a stable thermal state flow field with 4 tube rows and multiple columns (varied from 2 to 10) in staggered and in-line arrangement, were carried out to analyze the rules of the heat transfer and flow characteristics under different tube rows to obtain the influence rules of flowing around front tubes on the resistance of back rows. In order to obtain the influence rules of the number of tube rows on the resistance characteristics, bundle resistance correction coefficient was defined and values were given according to a series of experimental data. Rate of relative field synergy based on the field synergy principle was defined to characterize the ratio of the overall heat transfer efficiency relative to the actual maximum heat transfer with different numbers of tube rows. The results showed that the flow disturbance around the tail was the major factor in the deterioration of the resistance and the enhancement of the heat transfer, the flow fields up to 10 rows were well-distributed with the minimum influence of the flow disturbance around the tail and small synergy angles, the flow fields within 10 rows should be corrected with tube row correction factor.

Key words: resistance characteristic, rate of relative field synergy, heat transfer characteristic, bundle resistance correction coefficient, field synergy