Transient responses of the flat evaporator loop heat pipe

Wukchul Joung, Keesool Gam, Kwangmin Park, Sungpil Ma, Jinho Lee

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Despite the increasing interest on the loop heat pipes, the uncertainty due to the paucity of reported data on the transient responses makes the widespread application of these devices limited. In this work, a flat evaporator loop heat pipe (FELHP) was developed using a specially devised vapor-liquid separator, and the transient responses of the FELHP were thoroughly examined. Included are the transient responses to start-ups, sinusoidal heat input with various periods and amplitudes, abrupt heat load decreases, and termination of the operation. The FELHP developed herein showed a stable steady state operation from the minimum start-up heat load of 40-140 W. As for the transient responses to the sinusoidal heat input, the FELHP showed the minimum effective period below which it practically did not respond to the heat load variation, and the amplitude dependence of the minimum effective period was observed. In addition, from the comparison of the sinusoidal heat input and the abrupt heat load decrease responses, the mode of heat load decrease was found to be an important influential factor to the operation failure of the FELHP as was the magnitude of the heat load decrease. The FELHP also showed the sleeping mode operation at a very low heat load of 10 W, and the stable recovery to the steady state operation was quickly achieved when the heat load was recovered.

Original languageEnglish
Pages (from-to)131-141
Number of pages11
JournalInternational Journal of Heat and Mass Transfer
Issue number1
Publication statusPublished - 2013 Jan 15

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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