Numerical Investigation of the Hydraulic and Thermal Performance of Plain Fin Compact Heat Exchangers with Modified Flat Tubes

In cooling systems heat exchangers commonly use fin and cylindrical tubes. Flat tube configurations are generally used for high heat transfer purposes, but further optimization of tube configuration and overall geometry is required for better performance. In this study, numerical investigation of the hydraulic and thermal performance of plain fin tube heat exchangers with modified flat tubes using computational fluid dynamics has been done. Tube configurations with five different radius ratios were compared. Computational tools were used to conduct numerical simulations taking air as working fluid at Reynolds number(Re) 75 to 525 with a laminar model. The values for coefficient of heat transfer (h), pressure difference (∆P), goodness factor of area (AGF) and transfer of heat per unit fan power (Q/Pf) are calculated, which are presented graphically in our study. Furthermore, the study included the presentation of streamline patterns and temperature contours to assess the thermo-flow structures surrounding the tube. The findings indicated that decreasing the radius ratio from 1 to 0.33 decreases the pressure difference by 8.05% and 15.57% for 0.5 ms-1 and 3.5 ms-1 respectively. The overall thermal and hydraulic performance also increase with the decrease of radius ratio. These findings demonstrate that in heat transfer applications modified flat tubes can offer energy savings through reduced pressure difference and minimized separated flow structures.

American Institute of Physics