Study of the Influence of the Lack of Contact in Plate and Fin and Tube Heat Exchanger on Heat Transfer Efficiency under Periodic Flow Conditions

Plate fin-tube heat exchangers are widely used in air conditioning and refrigeration systems other industry fields. Various errors made the manufacturing process can result formation of an gap between tube fin. Several numerical simulations were carried out for a symmetric section plate exchanger to study influence on transfer under periodic flow conditions. Different locations sizes spanning 1/2 circumference considered range airflow velocities. Velocity temperature fields cases with compared ideal thermal contact cases. Blocking by leads reduction rate. Fin discontinuity front causes smallest rate comparison tube-fin contact, especially thin slits. The rear position is worst range. Therefore, reversing direction lead up 15% increase, if mainly gaps present. introduction slit convective enhancement, which should be further investigated.