Abstract:In heat transfer applications, heat pipes are widely- preferred because of some characteristics such as low cost, being able to be produced in any size and low maintenance cost make them superior. Moreover, the working fluid to be employed substantially affects the heat transfer characteristics of a heat pipe. In this paper, effects of nanoparticle addition into the ethylene glycol on heat pipe’s thermal performance were analysed experimentally. Every test was done using two variant working fluids, ethylene gl… Show more
“…It is seen that the liquid has the ability to wet at the contact angle. 31 Contact angle measurements are given in Figure 7.Figure 7.Contact angle measurements (a) POE, (b) nanolubricant, (c) hybrid nanolubricant.…”
Section: Resultsmentioning
confidence: 99%
“…It is seen that the liquid has the ability to wet at the contact angle. 31 Contact angle measurements are given in Figure 7.…”
Section: Characterization Analysis Of Nanoparticles and Nanolubricantmentioning
With a view to decreasing the energy consumption in cooling systems, many different methods have been used at the present time. One of these methods is the addition of solid nanoparticles to the compressor lubricant in order to increase the heat transfer surface. In this context, single and hybrid nanolubricants have been prepared by adding nano-sized iron (II, III) oxide (Fe3O4) and cerium oxide (CeO2) hybrid nanoparticles into polyol ester (POE) at different mass ratios by weight. 0.3% and 0.6% by weight of single Fe3O4 and hybrid Fe3O4 + CeO2 nanoparticles were added to this colloidal suspension separately. In addition, a 0.3% volume fraction of the surfactant triton X-100 (TX-100) was added to each suspension to avoid folliculations in nanolubricants. An experimental study was conducted under two different mass fraction single and hybrid nanolubricant to compressor section of the cooling system, respectively. The maximum improvement in coefficient of performance (COP) and the decrease in compressor work were found to be as 11.84% and 16.73%, respectively, when the hybrid nanolubricant was used as compressor lubricant.
“…It is seen that the liquid has the ability to wet at the contact angle. 31 Contact angle measurements are given in Figure 7.Figure 7.Contact angle measurements (a) POE, (b) nanolubricant, (c) hybrid nanolubricant.…”
Section: Resultsmentioning
confidence: 99%
“…It is seen that the liquid has the ability to wet at the contact angle. 31 Contact angle measurements are given in Figure 7.…”
Section: Characterization Analysis Of Nanoparticles and Nanolubricantmentioning
With a view to decreasing the energy consumption in cooling systems, many different methods have been used at the present time. One of these methods is the addition of solid nanoparticles to the compressor lubricant in order to increase the heat transfer surface. In this context, single and hybrid nanolubricants have been prepared by adding nano-sized iron (II, III) oxide (Fe3O4) and cerium oxide (CeO2) hybrid nanoparticles into polyol ester (POE) at different mass ratios by weight. 0.3% and 0.6% by weight of single Fe3O4 and hybrid Fe3O4 + CeO2 nanoparticles were added to this colloidal suspension separately. In addition, a 0.3% volume fraction of the surfactant triton X-100 (TX-100) was added to each suspension to avoid folliculations in nanolubricants. An experimental study was conducted under two different mass fraction single and hybrid nanolubricant to compressor section of the cooling system, respectively. The maximum improvement in coefficient of performance (COP) and the decrease in compressor work were found to be as 11.84% and 16.73%, respectively, when the hybrid nanolubricant was used as compressor lubricant.
Thermal management of electric and electronic components is a critical issue and needs to consider enhanced cooling systems such as heat pipes. This study deals with the theoretical modeling of a nanofluid-filled copper cylindrical heat pipe for electronics cooling applications. The heat pipe includes helicoidal and trapezoidal capillary grooves. The model can predict the capillary limit as well as the heat transfer in the different sections of the heat pipe. The thermal resistances of the evaporation and condensation sections are calculated based on correlations for heat transfer, which are determined from experiments. Two working nanofluids are considered: water/CuO and water/Al2O3. The thermal performances are predicted for different concentrations and heat sink temperatures, and the heat pipe is positioned horizontally. For both nanofluids, the results indicate that augmenting the concentration of the nanoparticles leads to a capillary limit increase reaching up to 14 % and 25 % for water/Al2O3 and water/CuO, respectively, and an overall thermal resistance decrease reaching up to 51 % and 68 % for water/Al2O3 and water/CuO. Moreover, decreases up to 24 %, and up to 18 % in the evaporator wall temperatures are obtained for water/CuO and water/Al2O3 nanofluids, respectively. The nanofluid water/CuO gives the best thermal performance whatever the nanoparticle concentration and heat sink temperature.
“…However, the physical mechanism of LHP is not well understood and there is still much room to be investigated further. It is noted that although the operating performance can be assessed by the external wall temperature of the loop [21,[33][34][35], some phenomena such as boiling in the core cannot be addressed reasonably due to lack of visualization of internal flow and heat transfer behaviors of the loop. Therefore, visualization study on the LHP is extremely necessary in order to reveal the operating mechanism from different angle.…”
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