• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.153-153
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• 2004

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2357-2362
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• 2008

LHP is different from a conventional heat pipes in design and heat and fluid flow passages. The situations of the former is much complex than the latter. In LHPs, evaporation occurs at the contact interface between the heating plate and the porous wick, so some micro channels machined at the contact interface serve to let the vapor flow out of the evaporator. This complexity of contact geometry was known to cause a high resistance to heat flow. The present work was to study the problem of heat passage across the contact surface for LHPs and determine those values contact resistance. For two cases of contact structures, the thermal contact resistances were examined experimentally, one being obtained through mechanical contact under pressure and the other through sintered bonding. Nickel powder wick and copper plate were used for specimens. The result showed that a substantial reduction of contact resistance of an order of degree could be obtainable by sintered bonding.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1475-1483
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• 2004

Loop thermosyphon(LTS) has many good characteristics such as low thermal resistance, no power consumption, noiseless operation and small size. To investigate the overall performance of LTS, we have performed various experiments varying three parameters: input power of the heater, working fluid(water, ethanol, FC3283) and filling ratio of the working fluid. At a combination of these parameters, temperature measurements are made at many locations of the LTS. The temperature difference between the evaporator and the condenser is used to obtain the thermal resistance. In addition, flow visualization using a high speed camera is carried out. The thermal resistance is not constant. It is lower at higher input power, which is one of the distinct merits of LTS. Flow instabilities are frequently observed when changing the working fluid, the input power and the filling ratio. The results show that the LTS can be readily put into practical use. Future practical application in electronic cooling is recommended.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1710-1716
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• 2008

The Loop Heat Pipe (LHP) operates to pump the working fluid by means of the capillary force in a wick structure. Particularly, it is difficult to design and manufacture the evaporator consisted of a grooved container and a compensation chamber as well as the wick structure. This study is related to design and manufacture the grooved container coupled with wick structure, the properties of the wick structure such as the permeability, the porosity, and the maximum capillary pressure were measured to apply the cooling technology for Insulated Gate Bipolar Transistor (IGBT). The container of the LHP was manufactured by the electrical discharge process and the wick structure was sintered with the nickel particle by an axial-press apparatus with the pulse electronic discharge. As results, the properties of the wick were experimentally obtained about 60% of the porosity, 35kPa of the maximum capillary force and $1.53{\times}10-13m2$ of the permeability.