COMPARISON OF THE PERFORMANCES BETWEEN THE CHANNEL AND THE CORRUGATED CHANNEL OF THE SPHERICAL CONVEX/CONCAVE FIN
Plate fin heat exchangers have been widely used in recent years because of their high efficiency, good reliability, low pressure loss, compact structure, light weight and low production cost. The dimples fin and wavy fin for plate fin heat exchanger can produce a strong secondary flow disturbance, which has a significant influence on the enhanced heat transfer characteristics in the duct. The purpose of present paper is to study by three-dimensional numerical simulation the heat transfer and fluid flow characteristics of dimples fin and wavy fin duct for plate fin heat exchanger at the range of v=2~6m/s. Comparison of average Nu, friction characteristics, secondary flow intensity and area goodness factor between the fin with dimples and the wavy fin at four different configuration. The results showed that average Nu of dimples fin duct is increased by 18% compared with wavy fin duct, while the average value of friction characteristics for dimples fin duct is also increased by 27.2% compared with wavy fin duct over the range of examined Reynolds number. Moreover, secondary flow intensity of dimples fin duct is decreased by 38% compared with wavy fin duct, thermal performance factor JF1 of dimples fin duct is increased by 14.4% compared with wavy fin duct, and thermal performance factor JF2 of dimples fin duct is increased by 13.5% compared with wavy fin duct. The results show that secondary flow intensity is generated by the wavy fin duct is higher than dimples fin duct, but heat transfer enhancement performance of dimples fin duct is higher than the wavy fin, namely, dimples fin is more conducive to convective heat transfer.