N2 - Plate fin-tube heat exchangers fins are bonded with tubes by means of brazing or by mechanical expansion of tubes. Various errors made in the process of expansion can result in formation of an air gap between tube and fin. A number of numerical simulations was carried out for symmetric section of plate fin-tube heat exchanger to study the influence of air gap on heat transfer in forced convection conditions. Different locations of air gap spanning 1/2 circumference of the tube were considered, relatively to air flow direction. Inlet velocities were a variable parameter in the simulations (1– 5 m/s). Velocity and temperature fields for cases with air gap were compared with cases without it (ideal thermal contact). For the case of gap in the back of the tube (in recirculation zone) the lowest reduction (relatively to the case without gap) of heat transfer rate was obtained (average of 11%). The worst performance was obtained for the gap in the front (reduction relatively to full thermal contact in the average of 16%). L1 - http://www.czasopisma.pan.pl/Content/109069/PDF/05_paper.pdf L2 - http://www.czasopisma.pan.pl/Content/109069 PY - 2018 IS - No 3 EP - 83 KW - heat transfer KW - heat exchanger KW - computational fluid dynamics A1 - Andrzejewski, Dariusz A1 - Łęcki, Marcin A1 - Gutkowski, Artur PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences VL - vol. 39 DA - 2018.10.10 T1 - Study of the influence of the lack of contact in platefin and tube heat exchanger on heat transfer SP - 63 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/109069 T2 - Archives of Thermodynamics