Study on heat transfer enhancement of discontinuous short wave finned flat tube

The typical configuration adopted by air-cooled condenser (ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can suppress the air-side heat transfer enhancement to a great extent. It has been proved that the serrated fins can enhance heat transfer obviously by breaking the development of boundary layer periodically. In the present study, the discontinuous short wave fin was introduced to the flat tube to enhance the air-side heat transfer of ACC. Two different types of arrangements, i.e. staggered and in-line for discontinuous short wave fins on the flat tube, were designed. By numerical simulation, the heat transfer and flow performances of short wave fins were studied under different arrangements (in-line, staggered), and the influences on heat transfer and flow characteristics of rows of short wave fin and interrupted distance between discontinuous short wave fins were revealed numerically. The results indicated that, compared with the original continuous wave fin, the discontinuous short wave fin effectively improved the air-side heat transfer of flat tube under the air flow velocities in the practical application of engineering. Moreover, the increment of pressure loss of air-side flow was restricted for the discontinuous short wave fins because of the reduction of contact areas between the air flow and fin surface.