New models for predicting the thermal-hydraulic characteristics of offset s
trip fin arrays are developed. These models are developed by combining the
asymptotic behaviour for the laminar and turbulent wake regions. Models in
these two regions are developed by considering the offset strip fin as an a
rray of short ducts or channels. The proposed models are compared with publ
ished experimental data for nineteen configurations of the rectangular offs
et strip fin. Model predictions are within +/- 20 percent for 96 percent of
friction factor data and 82 percent for Colburn j factor data. Extension o
f the new models for offset strip fins having non-rectangular subchannels i
s also discussed.