Boiling Heat Transfer Of Nanofluids Research Articles

A Novel Numerical Method for Simulating Boiling Heat Transfer of Nanofluids

A Novel Numerical Method for Simulating Boiling Heat Transfer of Nanofluids

Lattice Boltzmann Method for Fluid-Thermal Systems: Status, Hotspots, Trends and Outlook

Great advances have been made with the lattice Boltzmann (LB) method for complicated fluid phenomena and fundamental thermal processes over the past three decades. This paper presents a systematic overview of the LB method from 1990 to 2018, based on bibliometric analysis and the Science Citation Index Expanded (SCI-E) database. The results show that China took the leading position in this field, followed by the USA and UK. The Chinese Academy of Sciences had the most publications, while the Los Alamos National Laboratory was first as far as highest average citation per paper and h-index are concerned. Physical Review E was the most productive journal and “Mechanics” was the most frequently used subject category. Keyword analysis indicated that recent research has focused on the natural convection and heat transfer of nanofluid or multiphase flow in complex porous media. Hydrothermal treatment of nanofluid with shape factor on the conditions, such as variable magnetic fields, thermal radiation and slipping boundary, were the research hotspots. Further research perspectives mainly explore the multiscale models for coupling multiple transport phenomena, morphology optimization of porous parameters, new nanoparticles with shape factor, multicomponent LB method considering Knudsen diffusion effect, LB-based hybrid methods, radiation performance or boiling-heat transfer of nanofluid, and the active control of droplets, may continue to attract more attention. Moreover, some new applications, such as phase change of metal foam, erosion induced by nanaofluid, anode circulating, 3D modeling in thermal systems with vibration, and magnetohydrodynamics microfluid devices, could be of interest going forward.

Effect of Various Parameters on Boiling Heat Transfer of Nanofluids

Effect of Various Parameters on Boiling Heat Transfer of Nanofluids

An Experimental Investigation of Nucleate Pool Boiling Heat Transfer of Nanofluids From a Hemispherical Surface

ABSTRACTAn experimental investigation of nucleate pool boiling heat transfer is carried out using SiO2 nanofluid in atmospheric pressure and saturated conditions. The results show that the nucleate boiling heat transfer coefficient (HTC) of the nanofluids is lower than that of deionized water, especially in high heat fluxes. In addition, the experimental results indicate that the critical heat flux (CHF) improves up to 45% with the increase of the nanoparticle volume concentration. Atomic force microscopy images from the boiling surface reveal that the nanoparticles are deposited on the heating surface during the nanofluid pool boiling experiments. It is found that the boiling HTC deteriorates as a result of the reduction in active nucleation sites and the formation of extra thermal resistance due to blocked vapor in the porous structures near the heating surface. Furthermore, the improvement of the surface wettability causes an increase in CHF. Based on the experimental investigations, it can be concluded that the changes in the properties of the boiling surface are mainly responsible for the variations in nanofluids boiling performance.

Investigation on the Effect of Type and Size of Nanoparticles and Surfactant on Pool Boiling Heat Transfer of Nanofluids

In our efforts to improve the pool boiling heat transfer of water, three sets of experiments are carried out to investigate the best coolant for heat removal among alumina, silica, and zinc oxide as nanoparticles and water as base fluid: (a) pool boiling heat transfer of γ-alumina/water nanofluid with and without surfactant in both distilled water and treated water as base fluids, (b) pool boiling heat transfer of silica/water nanofluid with two different nanoparticle sizes, and (c) pool boiling heat transfer of zinc oxide/water nanofluid with surfactant. In all the above experiments, the effect of heater surface on boiling heat transfer coefficient has been investigated by repeating the experiment using pure water on the coated surface before cleaning it. Moreover, two effective thermophysical properties of fluids, dynamic viscosity and surface tension, are measured to explain the boiling behavior of the nanofluids. The experimental results indicate that (a) the presence of γ-alumina in the base fluid enhances the pool boiling heat transfer coefficient, but sodium dodecyl sulphate (SDS) as surfactant deteriorates the performance of pool boiling heat transfer of γ-alumina/water nanofluid and (b) silica nanoparticles reduce the boiling performance of pure water. Moreover, the larger particle size of silica nanoparticles shows less reduction in heat transfer coefficient, (c) zinc oxide/water nanofluid is the best coolant among all the above-mentioned nanoparticles for heat removal.

A Correlation for the Prediction of Heat Flux for Nucleate Pool Boiling Heat Transfer of Nanofluid

Researchers searching for new cooling medium do not limit themselves to liquids alone. Suspension in common fluids with particles in the order of nanometers (typically 10–100 nm) in size is called ‘nano-fluids’. Cooling techniques are one of the vital points in industries and the way to develop the traditional fluids to a high thermal heat transfer fluid is crucial. Development of high thermal fluid as a nanofluid purely depends on the thermal and physical properties of base fluid and the particles dispersed in it and some other factors such as particle shape, particle size and the particle concentration. This paper explains the thermal properties of nanofluid, viz., thermal conductivity, specific heat and other thermal properties. An empirical correlation has been developed to predict the heat flux for nucleate pool boiling of nanofluids considering the effects of temperature, volume fraction and shape of the particle while neglecting Brownian motion of the nanoparticle, cluster/particle agglomeration and the development of the liquid layer over the plate surface. The predicted result has been compared with the Rohsenow equation and the experimental data of other investigators show a good agreement with the predicted data. Using this equation, heat transfer coefficient and heat transfer enhancement ratio of the nucleate pool boiling of Al2O3–water and TiO2–water nanofluids have been calculated. This enhanced thermophysical and heat transfer characteristics of the developed fluid dispersed with nanoparticles can be used for high heat transfer medium for future applications.

Introducing Nanotechnology into the Thermal and Fluids Curricula: Pool Boiling Heat Transfer in Nanofluids

Nanotechnology has generated a large amount of interest in recent years, especially among engineering educators. Our institution continues to be among the leading universities to offer undergraduate courses that involve students in experiential learning of nanoscience topics. This paper describes a new thermo-fluids laboratory module where engineering students undertake problem-based experiments with nanofluids. The equipment, process and student work and feedback for the laboratory module are presented.

Transient Characteristics of Pool Boiling Heat Transfer in Nanofluids

This study shows the transient characteristics of the pool boiling curves using nanofluid as the boiling fluid. This time-dependency is in sharp contrast to a unique steady-state pool boiling curve that is typically obtained for a pure fluid. Past nanofluids research has provided interesting information about the thermal characteristics for this potentially promising cooling fluid. Results from these studies have shown some extraordinary critical heat flux (CHF) values and thermal conductivity enhancement that is yet to be explained by existing theories and correlations. The nature of the pool boiling curve for a nanofluid is dependent on the nanoparticle concentration in the base fluid. Higher concentration nanofluids show a perceptible degradation in the boiling heat transfer (BHT) coefficient but have exhibited an enhanced CHF value (up to ∼80%) when compared to the CHF value of the base fluid (water). Another key observation has been in the significant deposition of nanoparticles on the heater surface. This fouling of the heater surface by nanoparticles is widely viewed as a main contributor that modifies the pool boiling curve of the base liquid. The deposition of the nanoparticles on the heater surface is dynamic and this in turn makes the nanofluid pool boiling curve exhibit transient characteristics.