Experimental Investigation of Heat Transfer and Resistance Characteristics of a Finned Oval-Tube Heat Exchanger With Different Air Inlet Angles

• Published in: Heat transfer engineering Vol. 35; no. 6-8; pp. 703 - 710
• Main Authors: Du, Xueping, Zeng, Min, Wang, Qiuwang, Dong, Zhaoyi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Philadelphia, PA Taylor & Francis Group 24.05.2014; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Applied sciences; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat exchangers (included heat transformers, condensers, cooling towers); Heat transfer; Pressure; Reynolds number; Nusselt number; Pressure drop; Heat exchanger; Finned tube; Inlet flow; Air; Oval shape; Experimental study; Performance; Heat transfer; Angle of incidence
• ISSN: 0145-7632; 1521-0537
• DOI: 10.1080/01457632.2013.837780

The air inlet flow direction is not orthogonal to the heat exchanger surface in many cases. To study the performance of the heat transfer and pressure drop of a heat exchanger with different air inlet angles, this paper shows the experimental system about a finned oval-tube heat exchanger inclined toward the air incoming flow direction. The heat transfer and pressure drop characteristics of four air inlet angles (90°, 60°, 45°, and 30°) are studied separately for the Reynolds number ranging from 1300 to 13000 in this study. The experimental correlations of Nusselt number and resistance coefficient of the air side are acquired. The results show that the overall heat transfer coefficients become smaller and smaller with the decrease of the air inlet angles, while the pressure drops have significant changes. The heat transfer performances of the heat exchanger under the three inclined air inlet angles are worse than that at 90°. Among the three inclined angles, the performance at 45° is the best under identical mass flow rate criterion and at low Reynolds number under identical pressure drop criterion; that at 60° is the best at large Reynolds under identical pressure drop criterion. Finally, some conclusions are attained about the effects of the air inlet angles on the heat transfer and pressure drop performance of the finned oval-tube heat exchanger.