Experimental investigation on the thermodynamic state of vapor plugs in pulsating heat pipes

Cited 0 time in webofscience Cited 0 time in scopus
  • Hit : 46
  • Download : 0
In the present study, the thermodynamic state of vapor plugs in micro pulsating heat pipes (MPHPs) is experimentally investigated. The experiments are performed using the silicon-based MPHP with 10 turns. The rectangular micro-channels engraved on the silicon wafer form a closed loop and have the width and the depth of 1 mm and 0.5 mm, respectively. The overall dimensions of the MPHP are 50 x 33.5 x 1.7 mm(3). Ethanol is used as the working fluid and the filling ratio is 47% on the average. A transparent glass wafer is bonded to the silicon wafer for flow visualization. The temporal variations in temperature and pressure of a vapor plug in the MPHP are obtained using micro-thermocouples and pressure transducers. The measured temperature and pressure data are fully synchronized in real time with the flow characteristics obtained through a high-speed photography. It is experimentally found that the thermodynamic state of a vapor plug in the MPHP depends on the presence of the liquid film surrounding the vapor plug. If a vapor plug is surrounded by the liquid film, the vapor plug is saturated and there is no temperature difference along the vapor plug. On the other hand, if a vapor plug is in direct contact with the dry wall without the liquid film, the vapor plug is superheated and there is a difference in the vapor temperature between the evaporator section and the adiabatic section. These results can pave the way to a thorough understanding of the thermo-hydrodynamic coupling in PHPs. (C) 2019 Elsevier Ltd. All rights reserved.
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Issue Date
2019-05
Language
English
Article Type
Article
Citation

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, v.134, pp.321 - 328

ISSN
0017-9310
DOI
10.1016/j.ijheatmasstransfer.2019.01.053
URI
http://hdl.handle.net/10203/261018
Appears in Collection
ME-Journal Papers(저널논문)
Files in This Item
There are no files associated with this item.

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0