Mixture Of Glycol Research Articles

Thermophysical characterization on water and ethylene glycol/water-based MgO and ZnO nanofluids at elevated temperatures: An experimental investigation

In the current work, the main objective is to investigate the dynamic viscosity, thermal conductivity and isobaric specific heat capacity of MgO and ZnO nanoparticles that are dispersed in water and mixtures of ethylene glycol and water (EG/W). The measurements were carried out with various volumetric fractions (0.25 to 1%) and temperatures varied from 40 to 120 °C. According to the experimental results, the viscosity and thermal conductivity of the investigated nanofluids rise uniformly with increasing the nanoparticle concentration. The maximum viscosity augmentation for 1% MgO-(50:50)EG/W nanofluid is 34.5%, while the maximum augmentation for 1% ZnO-(50:50)EG/W nanofluid is 45.1%. For MgO-EG/W nanofluids, the maximum percentage of thermal conductivity enhancement occurs at 1% nanoparticles fraction and is 33.1%; for 1% ZnO-EG/W, the maximum enhancement is 23%. Measurements revealed that the nanofluids’ isobaric specific heat decreases as the nanoparticles fraction and EG concentration ratio in the base fluid increase but augments as the temperature increases. New correlations for predicting nanofluids’ thermophysical characteristics were suggested depending on the current experimental results. A theoretical evaluation of heat transfer performance was carried out, and it was demonstrated that MgO and ZnO nanofluids have the potential to be used in heat transfer applications with laminar flow regimes. For the turbulent regime, it is preferable to utilize nanoparticles concentrations of <0.5% for ZnO nanofluids and ≤1% MgO nanofluids, respectively.

Novel surface carbon–oxygen-groups grafted TiO2 for selective catalytic reduction of NOx by NH3 at low temperature

Activated coke (AC) with has excellent low-temperature NH3-SCR denitration performance due to its abundant surface-active functional groups including carbon species, while it is easy to burn during industrial application. Herein, a novel surface carbon–oxygen-groups grafted TiO2 was constructed by calcining the solid mixture of polyethylene glycol (PEG) and TiO2. The prepared 0.4PEG/0.6Ti catalyst shows good NH3-SCR denitration activity, and its NOx conversion was up to 80 % above 210 °C, while the pure AC exhibited poor activity. Characterization results suggest that the superior catalytic activity of 0.4PEG/0.6Ti catalyst is mainly attributed to the formation of lactone and carboxyl groups, which can promote the adsorption and activation of NO and NH3 species. Furthermore, NH3 as the reactant can also inhibit the decomposition of carbonyl groups due to over-oxidation, thus 0.4PEG/0.6Ti catalyst has good long-term stability. The reaction mechanism study reveals that the NH3-SCR reactions over catalysts follow the E-R and L-H mechanisms. Finally, the desulfurization-regeneration-denitration test (imitated activated coke simultaneous desulfurization and denitrification process) was carried out, and the results confirm that the prepared PEG/Ti catalyst could be regenerated for denitration after desulfurization. We expect that this work can provide some guidance for the design of low-temperature denitration catalysts.

An experimental study on thermal efficiency of hybrid GO/MWCNTs nanoparticles suspended in a binary mixture of ethylene glycol and water

Energy consumption has a demand growth across the globe due to modernization. However, the use of fossil fuels is creating a huge impact on climate change and has made it essential to harvest solar renewable energy technology. The heat transfer fluid plays an important role in maintaining the optimum temperature of the panel by removing the heat absorbed and transferring to the thermal energy storage medium. Due to the poor thermal conductivity and thermal degradation of conventional heat transfer fluids such as water, ethylene glycol and oil, these pose limitations to be utilised in solar energy technology systems. Thus, to overcome this problem, a hybrid nanofluid is used to boost the thermal conductivity and degradation temperature. However, the addition of hybrid nanoparticles further enhances the thermo-physical properties of the fluids. In this present study, GO/MWCNTs hybrid nanoparticles (0.01 – 0.2 wt%) were dispersed in hybrid base fluid (EG/water) in the ratio of 40:60. The finding shows that for visual stability, MWCNT sediment was faster compared to GO while, hybrid GO/MWCNT, showed higher stability compared to the single nanoparticle. The TGA results show the higher thermal degradation temperature at 0.05 wt% of pure GO, pure MWCNT and hybrid GO/MWCNT with thermal degradation of 122.74 ℃, 118.93 ℃ and 119.26 ℃ respectively. The use of nanofluids acts as a clean fuel for electricity production and decreases CO2 emission, which can further promote sustainable development goals.

Numerical investigation on Enhancing Heating performance in Automotive Radiator

In this paper, the improvement of heat exchange in a compact heat exchanger that is used in the automotive cooling system is numerically studied due to the importance that this part of the automotive represents in removing the heat generated in the automotive engine. The study adopted CFD simulation to introduce a new design of radiator that included changing the geometry and material of the tube while maintaining the same cross-section area In addition, the study also included replacing the shape of the fins from the louver to plain fin with the increase in the number of tubes. The study used a water-Ethylene glycol mixture (50:50) as a hot fluid with four flow rates (10, 12, 18, 24) l/h, (75, 85, 95) °C inlet temperature, and air as a cold fluid with 1.5, 2.5, 4.5, 5.5) m/s and (35) °C inlet temperature. Through the results obtained, the designed model appeared to have a higher thermal performance than the standard model due to the material and shape of the tube and fins. The designed model performed well, achieving an improvement ratio of (18.6%) for the heat transfer rate, (13.8%) for the overall heat transfer coefficient for the hot fluid, and (29.8%) for the air-side heat transfer coefficient

Characterization of Fluorescence Tracers for Thermometry and Film Thickness Measurements in Liquid Coolants Relevant for Thermal Management of Electric and Electronic Components.

This study investigated a novel two-color LIF (laser-induced fluorescence) technique for thermometry in coolants relevant for electric components. In principle, this diagnostic enables thermometry in liquid flows but also a simultaneous determination of film thickness and film temperature, which is relevant, e.g., for jet impingement cooled electric components. Temperature measurements are based on a temperature-sensitive intensity ratio of special tracers realized by suitable band pass filters within the respective emission spectra. For this purpose, the heat transfer fluids Fragoltherm F12, Marlotherm LH, and a water-glycol mixture WG20 (80 vol.% water, 20 vol.% glycol) and its individual components were doped with suitable tracers. The tracer Eosin-Y was utilized for polar coolants (water, WG20, and glycol) and Nile red was utilized for non-polar solvents (Fragoltherm F12 and Marlotherm LH). The spectral LIF intensities were recorded for a wide range of temperatures (253-393 K), which are relevant for cooling of electric motors, batteries, and power electronics. Furthermore, absorption spectra were analyzed as well. The temperature-dependent fluorescence measurements revealed different behavior for the polar and non-polar solvents. A temperature increase in the polar solvents (water, WG20, glycol) led to a spectral shift of the emission peaks of Eosin-Y towards longer wavelengths (red-shifted), while the peaks of Nile red in the non-polar solvents (Fragoltherm F12 and Marlotherm LH) showed an opposite behavior and were blue-shifted. The highest average temperature sensitivity was achieved for Marlotherm LH (4.22%/K), followed by glycol (1.99%/K), WG20 (1.80%/K), water (1.62%/K), and Fragoltherm F12 (1.12%/K). These sensitivities are similar to or even much higher than the literature data of other LIF tracers, which were, however, not determined in those coolants. Consequently, the two novel proposed dyes for the studied heat transfer liquids enable a reliable temperature determination.

Thermal management of lithium-ion batteries using carbon-based nanofluid flowing through different flow channel configurations

In this study, a novel lithium-ion battery (LIB) thermal management system is developed, and its cooling performance for cylindrical 18,650 LIB cells under different discharging rates is experimentally observed. The experiments are carried out using indirect-type liquid cooling with single and dual aluminium serpentine channels with different flow configurations. The study includes the preparation of nanofluid using multi-walled carbon nanotubes (MWCNTs) at three different volume fractions (Vf) (0.15%, 0.3%, and 0.45%) in the mixture of ethylene glycol and water and compares their cooling performance with water and ethylene glycol-water mixture. At 0.45% Vf of MWCNTs, the maximum drop in the average temperature of the battery cells is observed about 6.9 °C, 10.2 °C, and 11 °C at 2.1C in a single-channel flow configuration, dual-channel with parallel flow configuration, and dual-channel with counter-flow configuration, respectively. Dual-channel with counter-flow configuration provides the best cooling performance in terms of temperature drops of 8.6–13 °C using different working fluids. When a counter-flow configuration is used, the battery module's temperature uniformity is very good, with a maximum deviation of 1.5–3 °C, well within the safe limit to prevent thermal runaway. The pressure drop for 0.45% Vf of MWCNTs is 13.3% and 14% higher than water for single-channel and dual-channel, respectively.

Prediction of refractive indices and molecular radii of binary mixtures of Polyethylene glycol (PEG-200,400) and cyclic ethers: Insight into molecular interactions

Using five refractive index mixing rules: Lorentz–Lorenz, Gladstone–Dale, Weiner, Heller, and Arago –Biot; refractive indices of six binary polymer mixtures have been determined at 303.15 K, under atmospheric pressure. The binary mixtures investigated here are PEG-200 + 1,3-Dioxolane, PEG-200 + Oxolane, PEG-200 + Oxane, PEG-400 + 1,3-Dioxolane, PEG-400 + Oxolane, and PEG-400 + Oxane. A good agreement has been observed between the obtained results and respective literature data for all these mixtures. The relative merit of refractive index mixing rules is assessed. Deviation in refractive index and reduced free volume values are also calculated using the refractive index data taken from the literature. Furthermore, the molecular radius of these binary polymer mixtures is computed with the help of the refractive index and molar volume data. In addition, an ideal mixing method is also employed to calculate the molecular radius of these systems.The molecular radius of these binary mixtures is found to be additive with respect to the mole fraction of the pure components. Finally, the results are discussed in terms of the intermolecular interactions among the constituent molecules.

Aggregation and adsorption behavior of cobalt‐based metallosurfactant in water–ethylene glycol media forming worm‐like micelles

AbstractThe cobalt based metallosurfactant cis‐chlorobis(ethylenediamine)hexadecylaminecobalt(III) chloride (CHCC) has been prepared and well characterized by utilizing elemental analysis, NMR (1H, 13C), FT‐IR and UV–Vis spectroscopy. The CHCC metallosurfactant shows thermal stability up to 168°C. The micellization behavior of the synthesized CHCC metallosurfactant has been investigated systematically by the tensiometric, conductometric, and fluorescence techniques. The critical micelle concentration (cmc) values of CHCC have been determined in various water–ethylene glycol mixtures ranging from 0 to 100 weight % of ethylene glycol at 293.15, 298.15, 303.15, and 308.15 K. The physicochemical parameters namely counterion binding constant, surface pressure, surface excess, surface area covered per CHCC metallosurfactant molecule, free energy minimum, standard free energies of micellization and adsorption, standard enthalpy and entropy of micellization, and Gibb's free energy of transfer have been calculated. The hydrodynamic diameters and zeta potentials of the CHCC metallomicelles have been measured by dynamic light scattering method. Transmission electron microscopy was employed to confirm the presence of worm‐like micelles.

Determination of fluorescence quantum yields and decay times of NADH and FAD in water–alcohol mixtures: The analysis of radiative and nonradiative relaxation pathways

Combined studies on fluorescence quantum yield of coenzymes NADH and FAD in water–methanol, water–ethanol and water–propylene glycol mixtures and on time-resolved fluorescence of these molecules under excitation at 450 and 355 nm by means of time-correlated single photon counting (TCSPC) method have been carried out. A novel model that allowed to separate the contributions from several excited state relaxation mechanisms to fluorescence dynamics in the pico- and nanosecond time domains and to fluorescence quantum yield was developed and used for analysis of experimental data. The results indicated the existence of at least two different nonradiative relaxation mechanisms in NADH and FAD: a relatively slow nanosecond and a much faster picosecond ones. The analysis suggested that the increase of NADH fluorescence quantum yield with all alcohols concentration occurred mainly due to relatively slow nanosecond non-radiative and radiative relaxation mechanisms related with the change of conformation distributions, while the picosecond fluorescence quenching was found to have practically the same and conformation-insensitive value in water–monohydric alcohol mixtures. Similar conclusion was made for NADH in water–propylene glycol solutions where however a moderate decrease of the picosecond quenching rate was determined at high propylene glycol concentrations that was attributed to a slowdown of picosecond quenching under high viscosity conditions. In the case of FAD the analysis suggested that the dramatic rise of fluorescence quantum yield with alcohol concentration was mostly due to the conformation-sensitive picosecond quenching. This conclusion supports the known mechanism of the picosecond fluorescence quenching in FAD through electron transfer reaction in the π-stacked conformation between isoalloxazine and adenine moieties. Radiative decay times in NADH and FAD were estimated from experimental data and found to be about 10 ns and 20–30 ns, respectively.

Multi-Disciplinary Analysis of Working Fluids on Thermal Performance of the High-Power Diesel Engine System

Multi-disciplinary analysis was performed to analyze and investigate the thermal performance during transient operation of a 2 L diesel engine system with two different cooling systems. The multi-disciplinary model consisted of the engine thermal management system (ETMS) comprising a zero-dimensional engine model that can simulate the engine performance, and a one-dimensional flow model for cooling and lubrication systems with a controller. By deploying this approach, we were able to model different physical domains, including mechanical for the engine and the dynamometer and thermodynamic for the heat exchangers. Therefore, the thermal performance of the ETMS could be numerically predicted and analyzed. To develop the ETMS model, the physical properties, the heat transfer model, and the pressure drop were modeled. The base fluid, a 50/50 mixture of water and ethylene glycol (EG), and an Al2O3 nanofluid with a 1.5% volume ratio were modeled based on the thermodynamic properties such as density, dynamic viscosity, thermal conductivity, and specific heat. Nanofluid, with its higher thermal conductivity and higher heat transfer coefficient, absorbed more heat from the combustion chamber through the water-jacket in the engine block. Therefore, the oil temperature for the nanofluid was effectively 2.5 °C less than for the base fluid following the step-load condition. Simulation results showed the better effect of nanofluid on thermal performance. The total flow rate of nanofluid decreased by 2.2 L/min, although the flow rate through the radiator with nanofluid increased by 0.81 L/min to obtain greater heat dissipation. Eventually, the piston and the liner temperatures with the nanofluid were drastically reduced by 7.55 and 8 °C, respectively, compared to those of the base fluid. Finally, when nanofluids was applied in automotive cooling systems, the temperature of the piston decreased by 7.3 °C due to the reduced overall thermal resistance from combustion chambers to outside air. The effect of working fluid on the diesel engine system could be predicted through the multi-disciplinary model.

Facile synthesis of magnetic hierarchical porous carbon and the adsorption properties

In this work, hierarchical porous carbon materials with meso-macro porous were simply synthesized by only adding FeCl2 to the phenolic resin (PF). Here, macro porous was achieved by changing the polymerization kinetics of the resin-ethylene glycol mixture during curing through FeCl2, thus a tunable average pore size distribution from 50 nm to 190 nm obtained. In addition, iron can catalyze the carbon-water gasification reaction during the carbonization process, resulting in a mesoporous structure of about 3.5 nm. Besides, the prepared porous carbon material with a metal ion content of 2% was applied to remove organic pollutants in wastewater, which the adsorption capacity for methylene orange (MO) can reach to 175.91 mg g−1. Meanwhile, the porous carbon can be separated and recovered from the suspension simply by magnetic force, and its saturation magnetization was 10.8 emu g−1. Overall, the prepared porous carbon materials have good adsorption properties, and can be used as an optional candidate for magnetic separation super sorbent designed to remove MO or even other dyes in wastewater.

Multicomponent vapor-liquid equilibrium measurements and modeling of triethylene glycol, water, and natural gas mixtures at 6.0, 9.0 and 12.5 MPa

Triethylene glycol (TEG) is commonly used for natural gas dehydration, and with subsea processing facilities on the rise, an increasing interest is being shown in complex phase equilibria involving petroleum fluids and polar compounds. In this study, examples of such phase equilibria have been studied. New measurements for multicomponent vapor-liquid equilibrium (VLE) of TEG/Water/Natural Gas systems have been performed at pressures ranging from 6.0 MPa to 12.5 MPa and temperatures in the range 15 °C to 40 °C. Two types of natural gas, a Synthetic Gas (xCH4=0.62) and a Real Gas (xCH4=0.92), were mixed with an aqueous TEG solution, with TEG weight percentages ranging from 95 wt.% to 99 wt.%. Glycol in gas (y1), water in gas (y2), and gas solubility in liquid (xNG) were measured with relative experimental uncertainties below 32%. Since the systems are highly associating, the Cubic-Plus-Association (CPA) equation of state (EoS) was selected to model their phase behavior . Different association schemes (4C, 4F, 5F, 6F and 5C) were tested for TEG, and the classical 4C scheme is shown to perform best. The CPA EoS performed in general terms well, considering the number of components in the systems, the associated complexities, and high measurement uncertainty for such low concentrations (<1 ppm) in the gas phase. Furthermore, the content of N2, CO2, CH4 and ethane were modelled in the liquid phase at various conditions.

Thermal Performance of Car Radiator Operated by Al2O3–Ethylene Glycol/Water-Based Nanofluids: A Computational Fluid Dynamics Study

Abstract This study analyzed the heat transfer potential of nanofluids (suspension of Al2O3 nanoparticles in 60:40 mixtures of ethylene glycol and water by volume) compared to the base fluid by modeling the flow in both laminar and turbulent flow regimes in a flat tube of a radiator using both single-phase and Eulerian–Eulerian multiphase approaches of computational fluid dynamics (CFD) simulation. Nusselt number is calculated by varying the Reynolds number for both the models and compared with the theoretical correlations and the experimental data available in the literature. The effect of change in volumetric concentrations, inlet velocities, inlet temperatures, and particle sizes on the heat transfer performance parameters of nanofluids was evaluated. The multiphase approach showed a 5–45% greater increase in Nusselt number than the single-phase approach for the same volume fraction up to 1% and thereafter multiphase approach showed an even higher Nusselt number. The multiphase model revealed that raising the volume fraction up to 2% increases the Nusselt number of nanofluid by approximately thrice that of the base fluid but after that further increase in volume fraction does not show any significant increment. With the increase in Reynolds number, the Nusselt number, as well as surface heat transfer coefficient, increased for both laminar and turbulent flow regimes. Skin friction coefficient, pressure drop across inlet and outlet, and pumping power required increased slightly with the increase in volume fractions. Also, on varying the nanoparticle size, superior performance was observed at the particle size of 25 nm.

Effect of temperature and propylene glycol as a cosolvent on dissolution of clotrimazole

Herein, the solubility study of clotrimazole was performed in a propylene glycol+water system. The solubility values were fitted to various cosolvency equations. The model accuracies were studied with the computation of the mean relative deviations. The thermodynamic behavior was investigated according to the van't Hoff and Gibbs equations for clotrimazole in the propylene glycol+water system. Furthermore, the density data for clotrimazole were determined in mixtures of propylene glycol+water and fitted to the Jouyban-Acree equation.

Selective determination of 2,4,6-Trinitrotoluene (TNT) with cysteamine in deep eutectic solvents

2,4,6-trinitrotoluene (TNT) is one of the most widely used explosives for military and civilian purposes. Detection of TNT is very important for both human health and public safety. In this study, TNT determination was carried out using a new solvent medium containing cysteamine (CysN) without the need for noble metal nanoparticles (i.e. CysN-AuNPs used for anchoring CysN through S-atom) or strong alkalinity (i.e. to stabilize TNT-Meisenheimer anions in aqueous medium). CysN was prepared in a deep eutectic solvent (DES) consisting of a mixture of choline chloride and ethylene glycol, and the color of the Meisenheimer complex was derived from the donor–acceptor interaction between the amine group on CysN and the nitro group on TNT. The Lewis base-acid neutralization product, CysN-TNT charge-transfer complex, was stable in the optimized DES solvent unlike that in water. The absorbance of the resulting red complex was measured at 515 nm. The LOD and LOQ values were found to be 67.17 and 223.90 μg L− 1, respectively. The proposed method was not affected by similar explosives, camouflage agents, and possible ion interference in the soil. Finally, the method was validated with an HPLC-DAD analysis. This method is the first study to use DESs in the determination of energetic materials such as TNT and the proposed assay shows excellent selectivity for TNT. The proposed method stands out as it is fast, simple, of low cost, compatible with green chemistry with the potential to convert to a paper-based colorimetric sensor.

(Invited) Concentrated Hydrogen Bonded Electrolytes: Definition and Bulk & Interfacial Properties

We broadly refer to deep eutectic solvents (DESs) as concentrated H-bonded electrolytes (CoHBEs) where a composition specific to the “deep eutectic temperature” does not have to be met as long as the electrolyte possesses high salt concentration of the salt or the redox active specie and suppressed volatility are desired in energy storage, electrocatalysis, and electrodeposition processes. Liquid heterogeneity owing to H-bonding, similar to ionic liquids and DESs, CoHBEs present distinct electrode-electrolyte interfacial behavior.As a way to probe the electrode-electrolyte behavior of CoHBEs as a function of composition, we have performed electrochemical impedance spectroscopy and surface enhanced Raman spectroscopy (SERS). The potential dependent differential capacitance of choline chloride and ethylene glycol (1:2, 1:4, 1:6 molar ratio) mixtures do not present camel shaped curves as in the case of more extreme examples of concentrated electrolytes such as ionic liquids. The interfacial behavior is more similar to dilute systems, however, the H-bonding network presents a less mobile diffuse layer. While on glassy carbon, there is no specific ion adsorption, on metal electrodes chloride adsorption is observed. In chloride-free systems that are based choline oxalate mixed with ethylene glycol, capacitance is measured to be almost independent of the applied voltage on glassy carbon and gold. This is attributed to the strong binding energy of the solvation structure, as determined from theory, that hinders voltage-induced reorientations. Consistent to this behavior, the oxalate system also presents a very high viscosity. In addition, the voltage sweep range is limited in the case of oxalate system as it has narrower electrochemical window. On the other hand, choline acetate, which has a very similar chemical structure to the oxalate, undergoes specific ion adsorption particularly on gold electrode at a positive applied potential as confirmed by SERS. This is believed to be due to the reduced binding energy as calculated by density functional theory with -1 charge of the acetate in comparison to -2 charge in oxalate that leads to the desolvation and then the surface adsorption of the acetate. In the case of the choline bis(trifluorosulfonyl)imide and ethylene glycol mixture, a wider electrochemical window accompanied by a dampened u-shaped capacitance was observed with no specific ion adsorption.This study presents tuning of DESs and more broadly CoHBEs in terms of the bulk physical properties, the interfacial behavior near an electrode, and the coupled structuring effects through the variation in anion charge density and the extent of H-bonding.

Effects of Thermal Cycling Rate on the Glass Transition Behavior of Choline Chloride and Ethylene Glycol Deep Eutectic Solvent Mixtures

Deep eutectic solvents (DESs) are a class of mixtures with the potential to serve as designer materials, and substitute for conventional organic solvents used in a wide variety of applications. The eutectic behavior of these mixtures has been explored in some depth, but the characteristic tendency of these materials is to behave contradictory to ideal, anticipated behavior. Therefore, experimental analyses are paramount to understanding the molecular dynamics of these materials. In this work, we have assessed a series of DESs using incremental compositions of Choline chloride (ChCl) and Ethylene glycol (EG). We have explored the rate dependence of glass phase transitions in these ChCl:EG mixtures using differential scanning calorimetry by quantifying the impacts of thermodynamic kinetics. The supporting evidence demonstrates that thermal cycling rate significantly affects glass transition temperatures, suggesting the importance of defining rate-independent transition temperatures for these mixtures.

(Invited) Concentrated Hydrogen Bonded Electrolytes with Ferrocene and Viologen for Redox Flow Batteries

We developed concentrated hydrogen bonded electrolytes (CoHBEs) derived from a mixture of choline chloride (ChCl) and ethylene glycol (EG) containing ferrocene and viologen redox species for redox flow batteries. CoHBEs are similar to deep eutectic solvents (DESs) in terms of having distinct physical properties including wide electrochemical window, and low volatility. However, CoHBEs do not necessarily meet the requirement of “deep eutectic temperature” at a specific composition of the parent compounds that form the DES. CoHBEs formed with viologen and ferrocene species in ChCl:EG demonstrate reversible redox reactions. More importantly, 0.5 M of a viologen derivative coupled with 1 M of a ferrocene derivative was achieved owing to the good solvent strength of ChCl:EG at 1:4 and 1:6 compositions. The resulting electrolyte presents about 2M equivalent concentration of the redox couple since the viologen derivative is able to undergo two successive electron transfer. A theoretical cell voltage of 1.35V is possible with this electrolyte. This presentation will discuss the electrochemical and transport properties of this electrolyte system, and their applicability in redox flow batteries as studied by spectro-electrochemical and flow cell experiments.

Simultaneous heat and mass enhancement in mixed convective flow of power-law fluid using hybrid nanoparticles

Heat conduction and solute diffusion in fluid have been used for modeling of simultaneous heat and mass transportation in non-Newtonian fluid obeying the power-law rheological constitutive model. For thermal and mass transport enhancement, nanoparticles (Cu and AlO ) are dispersed in a mixture of water and ethylene glycol (EG). Mathematical models with correlations for physical properties are solved numerically via the finite element method (FEM). Wall shear stress on the surface of the pipe is enhanced when the intensity of the magnetic field rises. The wall shear stress reduces as positive buoyancy force increases. However, when the buoyancy force is negative , the wall shear stress increases. When the Grashof number is raised, the heat transfer rate at the pipe's surface tends to rise. Similarly, as the Schmidt number rises, the mass flux rises as well. Numerical outcomes have predicted that the motion of fluid becomes fast as the curvature parameter is increased. Favorable Buoyancy force increases the thickness of momentum boundary layer flow, whereas opposing Buoyancy force is responsible of a decrease in thickness of momentum boundary layer flow. Joule heating is responsible of an increase in the thermal boundary layer. Wall shear stress on the surface of the pipe is enhanced when the intensity of the magnetic field is increased.

Performance analysis of liquid-based battery thermal management system for Electric Vehicles during discharge under drive cycles

The performance of an Electric Vehicle (EV) is determined by the battery pack's specific power, specific energy, self-discharging rate, and cycle life. However, these parameters are sensitive to temperature. Therefore, thermal management is the most critical factor defining a battery pack's performance in an EV. Even though thermal management of lithium-ion batteries has received a lot of attention, there has been minimal research on the performance of liquid based battery thermal management systems for Electric Vehicles for the actual drive cycles like the Indian drive Cycle and Federal Test Procedure (FTP-75) drive cycle. This study investigates the thermal behaviour of the Li-ion battery pack of an EV and the performance of a liquid-based battery thermal management system with various coolant options, such as Water, Water-Ethylene Glycol mixture, and Water-Propylene glycol mixture for both Indian Drive Cycle and FTP-75 (Federal Test Procedure) Drive Cycle. The numerical simulation is carried out for a battery pack with four modules, and liquid-based battery thermal management is designed at the pack level, considering the heat generated in the battery pack. The variation of battery pack temperature and cumulative energy consumption by the battery thermal management system (BTMS) is also investigated. The simulation model is designed in such a way that it tries to maintain a set battery pack temperature of 25 °C. Also, the effect of ambient temperature on the performance of the liquid cooling system has been analyzed. The results indicated that with the increase in ambient temperature the BTMS takes a longer time to cool the battery pack and cumulative energy consumption by the liquid based BTMS also increases for both the drive cycles. In the case of Water-Propylene glycol mixture, 25 % propylene glycol concentration is recommended, whereas in the case of Water-Ethylene glycol mixture, 50 % ethylene glycol concentration provides the best performance as both cumulative energy consumption by the battery thermal management system and temperature distribution in the battery pack are optimum.