Air inlet angle influence on the air-side heat transfer and flow friction characteristics of a finned oval tube heat exchanger

• Published in: International journal of heat and mass transfer Vol. 145; p. 118702
• Main Authors: Tang, Linghong, Du, Xueping, Pan, Jie, Sundén, Bengt
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: Air cooling; Air inlet angle; Air intakes; Computer simulation; Contractors; Energiteknik; Energy Engineering; Engineering and Technology; Finned oval tube heat exchanger; Heat exchangers; Heat transfer; Heat transfer and flow friction characteristics; Maskinteknik; Mass flow rate; Mechanical Engineering; Noise control; Numerical methods; Performance evaluation; Pressure drop; Repair & maintenance; Teknik; Tube heat exchangers; Velocity distribution; Finned oval tube heat exchanger; Air cooling; Air inlet angle; Heat transfer and flow friction characteristics
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2019.118702

•Inlet flow angle effects on performance of finned oval heat exchangers revealed.•Experimental and computational investigation.•Flow inlet angle of 45° provided best heat transfer performance.•Flow inlet angle 30° gave worst heat transfer performance and the largest pressure drop.•Field synergy principle applied in the analysis. In this study, the influence of various air inlet angles on the heat transfer and flow friction characteristics of a 2-row plain finned oval tube heat exchanger is analyzed by experimental and numerical methods. The experimental results show that an air inlet angle 45° provides the best heat transfer performance, and an air inlet angle 90° provides the smallest pressure drop, while an air inlet angle 30° provides the worst heat transfer performance associated with the largest pressure drop. The 3-D numerical simulation results indicate that with the decrease of the air inlet angle, the uniformity of the air velocity distribution in the z-direction of the heat exchanger becomes worse. The heat transfer characteristics at different air inlet angles are analyzed from the prospective of the field synergy principle and the effect of the air velocity distribution uniformity. The overall heat transfer performance is also evaluated by the JF factor under the same air mass flow rate. The results show that the air inlet angle 45° offers the best overall heat transfer performance, next is the air inlet angle 60°, while the air inlet angle 30° has the worst overall heat transfer performance.