Abstract: In order to verify the reinforcement to heat transfer of direct air\|cooled single\|row tubes using vortex generators, 3\|D numerical simulations are performed to investigate air\|side heat transfer and flow characteristics of single\|row wavy\|finned flat tube with cylindrical\|shell trapezoidal wing using FLUENT 6.3. The results show that with Re ranging from 300 to 900, the heat transfer performance (Nu) and friction factor of single\|row wavy\|finned flat tube is increased by 123% and 111% respectively, after the cylindrical\|shell trapezoidal wing is used. The integrated heat transfer performance (Nu/f) of single\|row wavy\|finned flat tube increased up to 5.65% with cylindrical\|shell trapezoidal wing. It is concluded that the performance of single\|row wavy\|finned flat tube with cylindrical\|shell trapezoidal wing is better than that without cylindrical\|shell trapezoidal wing. In the process of simulation the actual situation of single\|row tubes is simplified. According to the symmetry, the computational domain is narrowed as far as possible. Because of checking of the grid independence, simulation results are reliable.