Effect of Reynolds number on heat transfer and flow for multi-oxide nanofluids using numerical simulation

A numerical simulation model for laminar flow of nanofluids in a pipe with constant heat flux at the wall has been built to study the effect of Reynolds number on heat transfer and pressure loss. The investigation was performed for metallic oxide and multi-oxide nanoparticles suspended in water. The thermal conductivity and dynamic viscosity were measured for a range of temperature (10–60 °C) and volume fraction of multi-oxide nanofluid. Comparison of the thermal conductivity for monocular oxide and multi-oxide nanofluids reveals a new way to control the enhancement in nanofluid conductivity. The numerical results obtained were compared with existing well-established correlations. The predictions of the Nusselt number for nanofluids are in agreement with the Shah correlation, and the deviation in the results is less than 1 %. It is found that the pressure loss increases with the Reynolds number, nanoparticle density, and volume fraction for multi-oxide nanoparticles. However, the flow demonstrates enhancement in heat transfer which improves with increasing Reynolds number of the flow.     

Pool boiling heat transfer characteristics of graphene-based aqueous nanofluids

Journal of Thermal Analysis and Calorimetry - In the present study, experiments on pool boiling heat transfer of graphene nanofluids on a flat heater surface (40 mm diameter) were...     

Experimental investigation on the heat transfer performance of MHTHS using ethylene glycol-based nanofluids

Journal of Thermal Analysis and Calorimetry - Energy storage plays an important role in improving the applicability of a wide range of energy systems. Buildings could be considered as a desirable...     

Research and development on composite nanofluids as next-generation heat transfer medium

Journal of Thermal Analysis and Calorimetry - Nanocomposite is a nanotechnology-based multiphase, high-performance composite material having combination of properties, which has been emerged as one...     

An updated review of nanofluids in various heat transfer devices

Journal of Thermal Analysis and Calorimetry - The field of nanofluids has received interesting attention since the concept of dispersing nanoscaled particles into a fluid was first introduced in...     

Experimental studies of flow boiling heat transfer by using nanofluids

Journal of Thermal Analysis and Calorimetry - Flow boiling heat transfer widely utilized in numerous industrial applications such as boiler tubes, evaporators and cooling of reactors in a nuclear...     

Study on backward-facing step flow and heat transfer characteristics of hybrid nanofluids

Journal of Thermal Analysis and Calorimetry - As high heat dissipation has increasingly become the primary factor restricting the capability of electronic elements, and the high temperature of the...     

Flow and heat transfer in non-Newtonian nanofluids over porous surfaces

In the present study, heat transfer and fluid flow of a pseudo-plastic non-Newtonian nanofluid over permeable surface has been solved in the presence of injection and suction. Similarity solution method is utilized to convert the governing partial differential equations into ordinary differential equations, which then is solved numerically using Runge–Kutta–Fehlberg fourth–fifth order (RKF45) method. The Cu, CuO, TiO₂ and Al₂O₃ nanoparticles are considered in this study along with sodium carboxymethyl cellulose (CMC)/water as base fluid. Validation has been done with former numerical results. The influence of power-law index, volume fraction of nanoparticles, nanoparticles type and permeability parameter on nanofluid flow and heat transfer was investigated. The results of the study illustrated that the flow and heat transfer of non-Newtonian nanofluid in the presence of suction and injection has different behaviors. For injection and the impermeable plate, the non-Newtonian nanofluid shows a better heat transfer performance compared to Newtonian nanofluid. However, changing the type of nanoparticles has a more intense influence on heat transfer process during suction. It was also observed that in injection, contrary to the other two cases, the usage of non-Newtonian nanofluid can decrease heat transfer in all cases.

     

A review on molten-salt-based and ionic-liquid-based nanofluids for medium-to-high temperature heat transfer

Molten-salt-based nanofluids and ionic-liquid-based nanofluids are developed for thermal storage and heat transfer at relatively high temperatures, in the past few years. Preparation and stabilization techniques are briefly introduced firstly, and then, thermal properties, e.g., specific heat, thermal conductivity and viscosity, are summarized and discussed in detail. The properties are not only affected by the characteristics of nanomaterials and base fluids, but also affected by the synthesis method, such as the sonication intensity and duration. Some of the thermophysical property data are still incomplete, especially the thermal conductivity of molten-salt-based nanofluids, and properties of ionic-liquid-based nanofluids at high temperatures. While several literature works show that the Krieger–Dougherty model can well predict the viscosity, no general models for thermal conductivity and specific heat have been developed yet for both types of nanofluids.

     

Characteristics investigation on heat transfer growth of sonochemically synthesized ZnO-DW based nanofluids inside square heat exchanger

Journal of Thermal Analysis and Calorimetry - In recent decades, the growth of heat transfer using nanomaterials in the conventional base fluid has caught the attention of researchers...     

An entropy production analysis for electroosmotic flow and convective heat transfer: a numerical investigation

Journal of Thermal Analysis and Calorimetry - In the current numerical study, an entropy production analysis is conducted for the electroosmotic flow and convective heat transfer in the microduct....     

Experimental investigation and optimization of loop heat pipe performance with nanofluids

Journal of Thermal Analysis and Calorimetry - High heat generation from electronic devices needs to cool down properly to prevent overheating. Loop heat pipe (LHP) is one of the excellent cooling...     

Heat transfer and friction factor analysis of MWCNT nanofluids in double helically coiled tube heat exchanger

Journal of Thermal Analysis and Calorimetry - The convective heat transfer rate and friction factor analysis are determined with the help of a double helically coiled tube heat exchanger by...     

Thermal analysis for heat transfer enhancement in electroosmosis-modulated peristaltic transport of Sutterby nanofluids in a microfluidic vessel

Viscosity plays a crucial role in the flow and heat transfer process of nanofluids. To effectively calculate and predict the changing characteristics of nanofluids viscosity, this study presents a theoretical model combining the static interface layer and dynamic Brownian motion mechanisms of spherical nanoparticles for water-based Newtonian nanofluids. The model describes the reasonable dependences of nanofluids viscosity on physical properties of nanoparticles (density, volume fraction, size) and base fluid (temperature, viscosity, density). Taking four kinds of typical water-based Newtonian nanofluids containing spherical oxide nanoparticles (Al₂O₃, CuO, SiO₂ and TiO₂) as examples, the prediction performance of different viscosity models is analyzed in detail. From the comparison studies, it is demonstrated that the new viscosity model developed in this paper can exhibit better prediction performance than many well-known theoretical models and empirical correlations. Not only do the predicted results of model agree well with the experimental data from various studies, but also the effects of different factors are reflected effectively.

     

Correction to: Thermal analysis for heat transfer enhancement in electroosmosis-modulated peristaltic transport of Sutterby nanofluids in a microfluidic vessel

Journal of Thermal Analysis and Calorimetry - The original article was published with typographical errors in the non-dimensionalization and parameters involved in the equations.     

Approaches for modelling of industrial energy systems: correlation of heat transfer characteristics between magnetohydrodynamics hybrid nanofluids and performance analysis of industrial length-scale heat exchanger

Journal of Thermal Analysis and Calorimetry - Numerical analysis is carried out on heat transfer performance of industrial-length double-tube heat exchanger, by using hybrid nanofluid as a coolant...     

Evaluation of heat transfer augmentation techniques based on their impact on entropy generation

This letter proposes to use entropy generation as a measure of the relative merit of heat transfer augmentation techniques relative to each other and to the heat exchange apparatus in which they may be incorporated. In this context, heat transfer augmentation techniques are viewed as design changes capable of reducing the irreversible destruction of useful energy (exergy) in heat exchange equipment. The entropy generation rate takes into account simultaneously the heat transfer and fluidd friction changes associated with implementing a heat transfer augmentation technique. Using in-tube roughness as an example, the letter shows what specific operating conditions must be met before the destruction of exergy can be reduced via heat transfer augmentation.     

Investigation of nanofluids on heat transfer enhancement in a louvered microchannel with lattice Boltzmann method

Numerical studies of laminar forced convective heat transfer and fluid flow in a 2D louvered microchannel with Al₂O₃/water nanofluids are performed by the lattice Boltzmann method (LBM). Eight louvers are arranged in tandem within the single-pass microchannel. The Reynolds number based on channel hydraulic diameter and bulk mean velocity ranges from 100 to 400, where the Al₂O₃ fraction varies from 0 to 4%. A double distribution function approach is adopted for modeling fluid flow and heat transfer. Code validations are performed by comparing the streamwise Nusselt number (Nu) profiles and Fanning friction factors of the present LBM and those of the analytical solutions. Good agreements are obtained. Simulated results show that the louver microstructure can disturb the core flow and guide coolant toward the heated walls, thus enhancing the heat transfer significantly. Furthermore, the addition of nanoparticles in microchannels can also augment the heat transfer, but it creates an unnoticeable pressure loss. With both the louver microstructure and nanofluid, a maximum overall Nu enhancement of 7.06 is found relative to that of the fully developed smooth channel.

     

A review of magnetic field influence on natural convection heat transfer performance of nanofluids in square cavities

Journal of Thermal Analysis and Calorimetry - The emergence of nanofluids as high-performance thermal transport media has drawn great research attention in the field of heat transfer. Owning to the...     

Connectionist intelligent model estimates of convective heat transfer coefficient of nanofluids in circular cross-sectional channels

Journal of Thermal Analysis and Calorimetry - The effect of Na2CO3 additive on the steam gasification characteristics of Sunjiahao (SJH) coal char was studied in the present paper. Na2CO3-catalyzed...