Numerical investigation on the thermal-hydraulic performance of high Prandtl number fluid in offset strip fin with different offset

Abstract

To rigorously analyze the thermo-hydraulic performance of offset strip fin operating with high Prandtl number fluid and variable fin offset values, numerical simulation was employed to investigate changes in the Colburn j and the Fanning friction f under varying fin offsets. The results, obtained using a reliable numerical model, indicated that an increase in offset led to a 33.08% and 33.97% rise in j and f, respectively, demonstrating the offset's influence on the thermal-hydraulic performance of offset strip fins. By employing orthogonal design techniques, a set of 49 design points for fin pitch, fin thickness, fin height, interrupted length, fin offset, Reynolds number, and Prandtl number were obtained. Regression analysis was conducted on the simulation results of these 49 design points, ultimately deriving correlations for j and f within the Reynolds number range of 100–1000 and the Prandtl number range of 2–13. A comparison between the predicted and simulated data revealed that j and f fell within the error range of 20% for 91.84% and 93.88% of the data, respectively, confirming the accuracy of the proposed correlations. Furthermore, comparing the correlations from this study with other previously established correlations demonstrated that the proposed correlations were more suitable for predicting the thermal-hydraulic performance of offset strip fins with high Prandtl number fluids. For fluids with Prandtl number range of 30–150, the predicted data of j and f exhibited errors within 15% and 20% of the experimental data, respectively, further validating the applicability of these correlations for predicting the thermo-hydraulic performance of offset strip fins with higher Prandtl number fluids as the working medium.