Experimental investigation of nanofluid stability on thermal performance and flow regimes in pulsating heat pipe

Akbari, Ali; Saidi, Mohammad Hassan

doi:10.1007/s10973-018-7388-3

Cited by 40 publications

(14 citation statements)

References 29 publications

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“…In addition, as reported in previous studies, 44,45 the existence of nanoparticles can increase the number of active nucleating sites in the evaporator section. The sedimented nanoparticles on the evaporator wall form cavities through which bubbles start to form.…”

Section: Resultssupporting

confidence: 60%

“…In addition, the existence of carbon nanosheets can increase the number of active nucleating sites in the evaporator section. As a matter of fact, the sedimented nanosheets on the evaporator wall act as nucleating sites that accelerate the boiling in the PHP 44,45 . Also, as reported in Table 2, the addition of high thermal conductive RGO nanosheets to the water results in higher thermal conductivity of the RGO nanofluids rather than pure water.…”

Section: Resultsmentioning

confidence: 97%

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The impacts of utilizing nano‐encapsulated PCM along with RGO nanosheets in a pulsating heat pipe, a comparative study

et al. 2021

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Summary Heat pipes are useful devices in heat transfer and particularly, in cooling systems. Given the high demand for cooling systems in various applications, an improvement in the performance of heat pipes has gained much attraction in recent years. In this study, the effects of utilizing working fluids with different thermal properties on the performance of pulsating heat pipes (PHP) are experimentally studied. Hence, nano‐encapsulated phase change material (NPCM), reduced graphene oxide nanosheets, and their mixture, as a novel hybrid nanofluid, are prepared and dispersed in water as a working fluid. NPCM at 3 concentrations of 5, 10, and 20 g/L, as well as nanosheets at three concentrations of 0.3, 0.6, and 1.2 g/L, are synthesized and investigated. Moreover, both additives are mixed at five various concentrations to form a hybrid nanofluid. All experiments are conducted in the vertical orientation and filling ratio of 50%. It is found that due to the increase in viscosity with the increment of concentration, the highest concentration is not always the optimum concentration and the PHP's performance for each additive is optimized in a specific concentration. NPCMs could prevent the working fluid's temperature to rise by changing the phase, as a result, the effective specific heat of the working fluid is slightly augmented. Also, the thermal conductivity of the working fluid increased up to 13% using nanosheets. It is illustrated that using the mixture of nanosheets and NPCM leads to a 38% decline in thermal resistance. Meanwhile, it is found that the enhancement in the thermal performance of the PHP using nanofluids is not only purely due to the increase in thermal properties of nanofluids but also due to the increase in turbulence intensity and boiling nucleation sites created by the nanoparticles. Highlights Nano‐encapsulated phase change material (PCM), reduced graphene oxide (RGO) nanosheets, and their mixture are used as working fluid in a pulsating heat pipe (PHP). The thermal performance of PHP is improved using PCM nanocapsules, RGO nanosheets, and their mixture. Nanosheets have a higher impact on the performance of PHP compared with nano‐encapsulated PCM. The better performance of PHP using RGO nanosheets is due to the higher thermal conductivity and mixing of fluid containing them compared with pure water. The better performance of PHP using nanocapsules is attributed to the better mixing of the fluid.

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Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 97%

The impacts of utilizing nano‐encapsulated PCM along with RGO nanosheets in a pulsating heat pipe, a comparative study

et al. 2021

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“…Stephen et al [21] examined the transfer performance of a compact loop heat pipe with alumina and silver nanofluid. Akbari and Saidi [22] have provided a research titled an Experimental investigation of nanofluid stability on thermal performance and flow regimes in pulsating heat pipe. In present study, the flow of Al2O3 and TiO2 Nano fluids in residential building plumbing systems were studied in laboratory under calm and turbulent flow conditions with different boundary conditions, different concentrations of Nano fluid.…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Nano Fluid Hydrodynamic Behavior of Al2O3 in Heating Systems of Residential Building

Alayi¹,

Zanghaneh²

2021

IJHT

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In plumbing systems and heat exchangers, of the important criteria for selecting common fluids such as ethylene glycol and water is to create a very low pressure loss, which as a result of this intrinsic feature, accurate flow measurement is possible. In present study, the numerical study of pressure loss and Nano fluid flow rate with base fluid has been investigated to measure other parameters. In present study, the flow of Al2O3 and TiO2 Nano fluids in residential building plumbing systems were studied in laboratory under calm and turbulent flow conditions with different boundary conditions, different concentrations of Nano fluid. The results show that the use of nanoparticles, especially metal nanoparticles in base fluids, leads to an increase in pressure loss, which is caused by the vortex currents created at the end of the pipe path, especially the parts where the sudden change in pipe cross section and also the bends.

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“…Isıl performans açısından en uygun yüzey aktif maddenin Triton X-100 olduğunu gözlemlemişlerdir [8]. Bu çalışmalara ek olarak titanyum dioksit [9,10], boksit [11], magnezyum oksit [12,13]ve çinko oksit [14] gibi materyallerle de nanoakışkan çözeltileri hazırlanmış ve bunların ısı borularında kullanımıyla performansta önemli artışlar elde edildiği görülmektedir.…”

Section: Gi̇ri̇ş (Introduction)unclassified

AlN/Saf Su Nanoakışkanının Isı Borusu Performans Parametreleri Üzerindeki Etkilerinin Deneysel Olarak Araştırılması

Çiftçi

2020

Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım Ve Teknoloji

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An aqueous nanofluid solution containing aluminum nitride (AlN) nanoparticles was prepared and tested in a plain heat pipe under different operating conditions. The thermal resistance and efficiency of the heat pipe, both of which are the performance indicators for heat pipes, were comparatively studied, and the alterations in temperature of the heat pipe wall were monitored. Figure A. The nanofluid preparation processPurpose: The aim of this study is to improve the heat transfer performance of a heat pipe via AlN/deionized water nanofluid. Initially, a nanofluid suspension consisting of AlN nanoparticles (60-70 nm) and Triton X-100 surfactant was prepared at the final volumetric concentration of 1.3%, and then tested in a heat pipe. Theory and Methods:The circular heat pipe used in the experiments was made of copper material with a wall thickness of 1 mm, an inner diameter of 13 mm and a length of 1000 mm. In order to observe the effects of nanoparticles, experiments were initially carried out for deionized water and then for nanofluid solution. In the experiments, the thermal resistance and efficiency of the heat pipe, both of which are the performance indicators for heat pipes, were comparatively studied, and the alterations in temperature of the heat pipe wall were monitored. The experiments were run under 150 W, 300 W, and 400 W heating power, and 3 g/s, 6 g/s, and 9 g/s cooling water mass flow rate conditions.Results: With the use of nanofluid containing aluminum nitride nanoparticles instead of deionized water as the working fluid, the maximum enhancements in thermal resistance and efficiency were recorded as 10.9% and 45.6%, respectively. Conclusion:Heat pipe wall temperatures and boiling point were reduced significantly by using nanofluid as a working fluid. When AlN nanofluid was used instead of deionized water, a decrease of up to 10.9% was achieved in the thermal resistance of the heat pipe. A maximum increase of 45.6% was obtained in the efficiency of the heat pipe with the usage of nanofluid. The benefits of using AlN nanofluid in the heat pipe were also been demonstrated.

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Experimental investigation of nanofluid stability on thermal performance and flow regimes in pulsating heat pipe

Cited by 40 publications

References 29 publications

The impacts of utilizing nano‐encapsulated PCM along with RGO nanosheets in a pulsating heat pipe, a comparative study

The impacts of utilizing nano‐encapsulated PCM along with RGO nanosheets in a pulsating heat pipe, a comparative study

Experimental Analysis of Nano Fluid Hydrodynamic Behavior of Al2O3 in Heating Systems of Residential Building

AlN/Saf Su Nanoakışkanının Isı Borusu Performans Parametreleri Üzerindeki Etkilerinin Deneysel Olarak Araştırılması

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