• Title/Summary/Keyword: R40

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Pool Boiling Performance of Enhanced Tubes for a Flooded Evaporator (만액식 증발기용 성형가공관의 풀비등 성능)

  • Kim, Nae-Hyun;Kim, Tae-Hyung;Park, Woon-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.1
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    • pp.124-131
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    • 2000

  • In this study, pool boiling performance of Turbo/B-type metal-formed tubes was investigated. Tubes with three different cavity gap width(0.04 mm, 0.07 mm, 0.1 mm) were manufactured and tested using R-11, R-123 and R-134a. Tests were conducted at two different saturation temperatures $4.4^{\circ}C$ and $26.7^{\circ}C.$ Heat flux was varied from 10 kW/m2 to 50 kW/m2. It was found that optimum gap width varied for different refrigerants. For low-pressure refrigerants such as R-11 or R-123, optimum gap width was 0.07 mm. For high-pressure refrigerant R-134a, however, the optimum value was 0.1 mm. Compared with the heat transfer performance of the smooth tube, the metal-formed tubes enhanced the heat transfer coefficients significantly - 6.5 times for R-11, 6.0 times for R-123 and 5.0 times for R-134a (at $4.4^{\circ}C$ saturation temperature and 40 kW/m2 heat flux), which are comparable with the performance of foreign products. The heat transfer coefficients of R-134a were larger than those of R-11 or R-123, and they increased as the saturation temperature increased.

  • https://doi.org/10.22634/KSME-B.2000.24.1.124 인용 PDF