The heat transfer and flow friction performance for the flow across tube banks with longitudinal trapezoid fins and rectangle fins are reported

and the difference of the performance between both tube banks is studied.This work analyses the influence of the pitch

fin height and width The different fins（trapezoid and rectangle）result in the difference of performance and by comparison the difference of heat transfer is about-ll％ ～34％

the greatest difference of flow friction is aboutl.2 times The trapezoid fin can gain the lower flow friction and the better com prehensive utilization of energy When banks are in a dense transversal arrangement the longitu dinally finned tube banks have lower flow friction and better heat transfer than the smooth tube bank.