Experimental Study on Condensation Heat Transfer Characteristics inside an Inclined Wave-Finned Flat Tube of Direct Air-
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https://doi.org/10.1007/s11630-020-1353-8
Article ID: 1003-2169(2020)00-0000-00
Experimental Study on Condensation Heat Transfer Characteristics inside an Inclined Wave-Finned Flat Tube of Direct Air-Cooling System WANG Haitao1,2*, TAO Tao1,2*, MEI Xuesong1,2, WANG Haijun3, GU Hongfang3 1. State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China 2. Shaanxi Key Laboratory of Intelligent Robots, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China 3. State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China © Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract: In this paper, the condensation heat transfer characteristics of parallel flow and counter flow inside an inclined wave-finned flat tube is investigated experimentally. The condensation heat transfer coefficients are analyzed based on the experimental results. Results of experiments show that condensation heat transfer coefficient decreases as the temperature difference ∆t=ts‒tw increases and mass flow rate decreases. The parallel flow has a similar development with the counter flow, and the condensation heat transfer coefficient of counter flow is less than that of parallel flow under the same air cooling conditions. In addition, condensation heat transfer coefficient correlations are also obtained under experimental ranges. The calculations agree well with the measured data and the agreement is seen to be within ±4% for the parallel flow and ±5% for the counter flow.
Keywords: condensation heat transfer, wave-finned flat tube, modified model, parallel flow, counter flow
1. Introduction Air-cooled condenser (ACC) is widely applied in the regions where it is rich in coal but short of water resource. Steam-side condensation determines the heat exchange efficiency of the air-cooling unit; however, studies on condensation heat transfer in air-cooled condenser (ACC) are very rare up to now. The steam condensation in condenser parent tubes relates to a complex vapor-liquid two-phase flow, and the condenser tube bundles are inclined arrangement, so the large non-circular section brings so much difficulty for studying in-tube condensation heat transfer characteristics. Most studies have been published, focused on heat transfer characteristics of convective condensation in the horizontal tube and vertical tube. Many scholars have Received: Apr 02, 2019 AE: JIA Li
done the theoretical and experimental researches, established a series of heat transfer coefficient empirical formulas and calculation models. Nusselt [1, 2] first studied the condensation heat transfer; he thought that the velocity profile on the vertical direction of the wall in the steam condensation process appeared to be conic, not linear. At the same time, the temperature profile on the vertical direction of the wall changed in a certain proportion; through testing the thin liq
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