Laboratory investigation and commercial test for rotors-assembled strand applied in smooth tube

Journal Article · Wed Oct 15 04:00:00 EDT 2008 · Experimental Thermal and Fluid Science

DOI:https://doi.org/10.1016/J.EXPTHERMFLUSCI.2008.04.005· OSTI ID:21116083

Li, Feng-Xiang; Ding, Yu-Mei; Guan, Chang-Feng; Xie, Peng-Cheng; Yan, Hua; Yang, Wei-Min ^[1]

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1. College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

In the commercial test for smooth tube inserted with rotors-assembled strand comparing with non-inserted ones on condensers in electric power plant, using water as working fluid, the single-phase pressure drop and heat transfer were measured. It was found difficult to receive reliable and accurate enough data through commercial test. Meanwhile, the single-phase pressure drop and heat transfer in a rotors-assembled strand inserted tube were measured in laboratory, with the tube side Prandtl numbers varying from 5.67 to 5.80 and the tube side Reynolds numbers varying from 21,300 to 72,200. Before that, a validation experiment based on the same smooth tube was carried out to testify the experimental system and the data reduction method, in which fixed mounts were employed to eliminate entrance effects. The Prandtl numbers varied from 5.64 to 5.76 and the Reynolds numbers varied from 19,000 to 56,000 in the tube. The annular side Reynolds numbers remained nearly constant at the value of around 50,000 for all experiments, with the annular side Prandtl numbers varying from 8.02 to 8.22. The experimental results of smooth tube show that employment of fixed mounts leads to a visible bias of friction factor at relative low Reynolds numbers while it hardly affects the Nusselt numbers. On the other hand, experiment for the tube inserted with rotors-assembled strand show remarkable improvement for heat transfer with the Nusselt number increased by 9.764-11.87% and the overall heat transfer coefficient increased by 7.08-7.49% within the range of Reynolds number from about 21,300 to 55,500. Meanwhile, friction factor increases inevitably by 278.1-353.9% within the same range of Reynolds number. Based on through multivariant linear normal regression method, the Reynolds number and Prandtl number dependencies of the Nusselt number and friction factor were determined to be Nu = 0.0031Re{sup 0.9}Pr{sup 1.0849} and f = 0.993Re{sup -0.22}. (author)

• OSTI ID: 21116083
• Journal Information: Experimental Thermal and Fluid Science, Journal Name: Experimental Thermal and Fluid Science Journal Issue: 1 Vol. 33; ISSN 0894-1777; ISSN ETFSEO
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
Commercial test
FRICTION FACTOR
HEAT EXCHANGERS
HEAT TRANSFER
Heat transfer enhancement
NUSSELT NUMBER
PRANDTL NUMBER
PRESSURE DROP
REYNOLDS NUMBER
ROTORS
Rotors-assembled strand
TUBES
WATER