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A correlation to predict heat-transfer rates of a miniature loop thermosyphon


This research is aimed at enhancing the traditional thermosyphon by preventing flooding and drying out from the opposite directions of the vapor and liquid. A miniature loop thermosyphon (MLT) consists of three sections, namely, the evaporator, the adiabatic and condenser sections. The return liquid channel is connected between the condenser and the evaporator to convey the condensed liquid. The MLT has a ratio of internal diameter of the condenser section to internal diameter of the evaporator section (Idc/Ide), which is 1.4. The MLT was made from a copper tube of 15-mm, 19-mm, and 22-mm ID. The filling ratios of the working fluid were 30%, 50%, and 80% of evaporator volume with an inclination angle of 90°. The operating temperatures were 70°C, 80°C, and 90°C with ratios of Ide/Idr of 3, 3.8, and 4.4. The research reports the effect of dimensionless parameters on heat-transfer characteristics, namely, Bo, Pr, We, Fr, Ja, Ku, ρ υ /ρ l, and Ide/Idr. It was found that the Bo, Pr, Ja, Ku, ρ υ /ρ l, and Ide/Idr have no effect on heattransfer characteristics. The We, Fr, and Ku have an effect on the heat-transfer characteristics as with increasing We, Fr, and Ku, the heat-transfer characteristics decrease. The research established another modified Kutateladze number, which can also be used to predict MLT in the vertical position.

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Correspondence to S. Rittidech.

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Dangeton, W., Rittidech, S., Pattiya, A. et al. A correlation to predict heat-transfer rates of a miniature loop thermosyphon. J. Engin. Thermophys. 22, 111–121 (2013).

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  • Heat Pipe
  • Froude Number
  • Condenser Section
  • Engineering THERMOPHYSICS