Integral spiral finned tubes have significant advantages versus conventional finned tubes like high frequency resistance welded spiral finned tubes and H-type finned tubes

and have broad application prospect in low pressure economizer. However

the thermal-hydraulic characteristics of integral spiral finned tube bundles are still not clear. The effects of fin height

fin pitch

transversal tube spacing and longitudinal tube spacing on resistance and heat transfer characteristics of integral spiral finned tube bundles are studied numerically in this paper. The overall thermal-hydraulic performance evaluation criteria η_0j/f~(1/3) considering fluid flow

convective heat transfer and solid heat conduction characteristics is proposed. The results indicate that

the predictive applicability of the Realizable k-ε model is the best. The overall thermal-hydraulic performance increases significantly with reducing transversal tube spacing while it remains unchanged with the change of fin pitch. The best overall thermal-hydraulic performance will be obtained when the relative fin height h_f/d_0 or relative longitudinal tube spacing S_L/d_0 are 0.32 or 2.89 respectively. Moreover

correlations of the Euler number and Nusselt number for 4-row staggered integral spiral tube bundles are presented

which may be useful for engineering application.