Nanofluid oscillating heat pipe

An Oscillating Heat Pipe (OHP) is a heat transfer device that can be utilized to transfer a large amount of heat from heating to cooling sections. A typical OHP is fabricated from a long capillary tube bent into many turns with an evaporator and a condenser located at two opposite sides, and an adiabatic region between the evaporator and condenser. In order to form a train of vapor bubbles in an OHP, the liquid and vapor must not be able to stratify in the channel. When nanoparticles are added in the base fluid in an OHP, the OHP effectively utilizes 1) the oscillating motion in the OHP to suspend nanoparticles; 2) the higher heat capacity of nanofluid; 3) the higher thermal conductivity; 4) the nanoparticle effect on the fluid field; and 5) the nanoparticle effect on the surface wetting conditions. The unique feature of the oscillating motion fully utilizes the nanofluid features to significantly enhance the heat transport capability in an OHP. In the fabrication process of OHPs, preparation, charging the OHP with nanofluids and sealing it are inevitable and requiring careful attention for successful testing. Nanofluid was first used as the working fluid in a 12-turn OHP by the Center for Thermal Management at the University of Missouri in 2006. The results of using nanofluids showed a significant improvement over results which used the traditional base fluid of water as the working fluid. The improvement was especially significant at low power; however, even at high power the improvement was measurable. The parameters affecting heat transfer performance were systematically investigated by researchers around the world. It was reported that the thermal resistance for the Al₂O₃-water nanofluid was lower than that of pure water, while the thermal performance of SiO₂-water nanofluid was worse than pure water. There is an optimal nanofluid concentration for the OHP. It is also worth noting that the effect of nanoparticle deposition on thin-film evaporation has not been investigated and might play a significant role in the thermal performance of the nanofluid OHP. 2013 Nova Science Publishers, Inc. All rights reserved.