Numerical investigation of the thermal-hydraulic performance of finned oblique-shaped tube heat exchanger

• Published in: 2016 15th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm) pp. 625 - 632
• Main Authors: Khoo, Kent Loong, Chuan Sun, Lewpiriyawong, Nuttawut, Poh Seng Lee, Siaw Kiang Chou
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2016
• Subjects: Air conditioning; Boundary conditions; Computational modeling; Electron tubes; elliptic tube; Heat transfer; Heating; oblique; plate fin and tube heat exchanger; Temperature
• ISSN: 1087-9870; 2577-0799
• DOI: 10.1109/ITHERM.2016.7517606

Plate fin and tube heat exchangers (FTHX) are widely used in HVAC applications due to the high effectiveness to cost ratio for heat transfer between two fluids. For air-cooled residential air conditioning unit applications, the overall efficiency of the unit is limited by the air-side heat transfer coefficient, which is much lower than that of the refrigerant-side. In this paper, oblique-shaped tube with the same tube area is introduced to replace the circular tube in FTHX to enhance the overall thermal-hydraulic performance of the air-side heat transfer. Numerical investigations of plain FTHX with circular tube, elliptic tube and oblique-shaped tube are conducted to analyze and compare the thermal-hydraulic performance. The results show that, although the heat transfer amount is comparable between the three finned tube designs, the pressure drop of the finned oblique-shaped tube is significantly lower by 53.6 - 58.7% than the finned circular tube at the same air inlet velocity. The oblique-shaped tubes have smaller frontal area and is streamlined, resulting in much smaller wake and lower flow velocity, thus significantly reducing the pressure loss. For a particular heat exchanger size and heat capacity, the fan power requirement for the finned oblique-shaped tube heat exchanger is the lowest.