Abstract: Air-cooled heat exchanger is one of the main components of the indirect dry cooling system in a power plant.It is of benefit to the optimal design and operation of indirect dry cooling system to clarify the flow and heat transfer characteristics of air-cooled finned tube heat exchangers.The thermo-flow performances of the commonly used finned tube bundles in air-cooled heat exchangers were investigated by a numerical simulation.The variations of the flow resistance and average convection heat transfer coefficient of cooling air through the finned tube heat exchanger with the windward velocity were presented.The correlating equations of the friction factor versus Reynolds number,and the Nusselt number versus Reynolds number were fitted.On the basis of the performance evaluation criteria for convection heat transfer,the expression of Nu/f1/3 was applied to the thermo-flow performances prediction for six finned tube bundles.The results show that as the windward velocity increases,the convection heat transfer is enhanced and pressure drop increases,resulting in the increased convection heat transfer coefficient and lowered friction factor.The increase of pressure drop is more conspicuous than that of convection heat transfer coefficient.For the integrated thermo-flow performances,the Forgo-type finned tube bundle is superior to the finned oval-tube one.The present studies are of use in finned tube selecting and optimal designing for the air-cooled heat exchangers of indirect dry cooling system.