Water Glycol Research Articles

Highly Selective Protic-Solvent-Mediated Organic-Inorganic Hybrid Cuprous Bromides Achieving Structural Transformation.

The potential application of stimuli-responsive hybrid copper halides in information storage and switch devices has generated significant interest. However, their transformation mechanism needs to be further studied deeply. Herein, two zero-dimensional (0D) organic-inorganic hybrids, namely, (TBA)CuBr2 (1) with linear [CuBr2]- units and (TBA)2Cu4Br6 (2) with [Cu4Br6]2- clusters (TBA+ = (C4H9)4N+), are synthesized using simple solvent evaporation approaches. Interestingly, upon exposure to distinct protic solvents, such as methanol, ethanol, ethylene glycol, or hot water, 1 undergoes a transformation into 2 with varying degrees of transition, accompanied by a change in luminescence color from cyan to orange (or mixed color) under high-energy emission (e.g., 254 nm) excitation. Hot water can trigger 1 to completely transform into 2 because of its large contact angle difference in the solvents. Furthermore, 2 can be converted back to 1 through a simple solid-state mechanochemical reaction. Additionally, the structure of 2 remains unchanged even after immersion in 80 °C H2O for 168 h due to the dense organic framework. This study provides valuable insights for exploring reversible structural transformation materials in the 0D metal halide system.

Reynolds number based optimization on liquid cooling system for permanent magnet synchronous motor of electric vehicle

The electric motor thermal management system (TMS) is a pivotal unit for electric vehicles (EVs). To study the factors affecting cooling performance and cooling efficiency of spiral housing water jacket (HWJ), simulations were carried out on a 150 kW jacked-cooled permanent magnet synchronous motor (PMSM) with ethylene glycol & water (EGW) as coolant. The coupling between channel numbers (N) and coolant flow rate (Q) on winding average temperature (T) and pressure drop (P) were investigated focusing on the Reynolds number (Re) via analytical and numerical thermal models. The results indicated that the cooling performance was nearly the same for coolant under fully turbulent. Both the cooling performance and cooling efficiency were not conducive when N > 8, and meanwhile, N < 6 also hindered the heat extraction. Resorting to the investigation, a Re-based multi-objective optimization algorithm was put forward. Compared the optimized jacket N6Q12 (denoting 6 channels with 12 L per minute flow rate) with the sub-optimized N12Q6 at the same Re, winding average temperature T was found 6.5 deg C lower, and pressure drop P was reduced by up to 71.6 %.

Purification and investigation of bio-glycerol as heat transfer fluid and as coolant in automobile radiators

Glycerol is a key by product of the biodiesel extraction process. The rapid growth of biodiesel establishments will continue to result in glycerol oversupply. Purified glycerol can be used as an antifreeze in automotive radiators since it has a freezing point of −30 °C and a boiling temperature of 160 °C. Heat transfer by automotive radiators is important in optimizing engine fuel economy. The goal of this research is to employ purified bio glycerol as a heat transfer fluid and a coolant in vehicle radiators. The proposed water mixed bio glycerol convective heat transfer rate is experimentally compared to standard ethylene glycol. The rate of heat transfer by bio glycerol is determined by passing the fluid through an automobile radiator test apparatus. For this objective, an Automobile Radiator test rig is devised and built. Experiments with distilled water blended bio-glycerol in volume ratios of 50:50, 70:30, and 60:40 were carried out, and the test findings revealed that the 70:30 water bio glycerol volume ratio created a higher heat transfer rate when compared to the water ethylene glycol mixture.

Insights of thermal characteristics with tri-hybrid nanofluid boundary layer flow past a thin needle

The innovative ternary nanofluid that we report herein is intended to improve the performance of heat transfer and thermal conductivity compared to conventional fluids. In view of the aforementioned significance, the goal of continuing research is to investigate the fluid flow and thermal efficiency of water-ethylene glycol (EG)-based ternary nanofluids (TiO2, MoS2, and CoFe2O4) past a thin needle that is subjected to a transverse magnetic field along the normal direction of the flow as well as resistive heating. The governing transport flow equations for ternary nanofluid have been converted into a system of ordinary differential equations using self-similarity variables and solved with the use of the BVP4C function in MATLAB. The significance of each flow factor on temperature and velocity profiles is illustrated using graphs, and the local Nusselt number, and skin friction parameters are computed. The study reveals that the addition of nanoparticles exerts a greater adverse effect on the exchange of heat, and it is found that the water-ethylene glycol based ternary nanofluid has a rate of heat transfer of up to 16% compared to hybrid nanofluid even at very low volume fractions (0.0025–0.03). It is inspected that in the presence of resistive heating, the ternary nanofluid has greater heat transfer than hybrid nanofluids. It is also observed that as the volume proportion of nanoparticles increases, the Nusselt number rises and wall friction decreases.

Experimental study of preparing the CoFe2O4 magnetic nanofluid and measuring thermal-fluid characteristics of the stabilized magnetocaloric nanofluid

The purpose of this study was to examine the rheological features of CoFe2O4 superparamagnetic nanoparticles dispersed in water-ethylene glycol (EG) coolant as the basis fluid. The experiments are carried out at temperatures between 10 and 50 degrees Celsius, with five mass fraction concentrations of magnetocaloric nanofluid as well as different shear rates. The solvothermal-produced cobalt ferrite metallic compounds are disseminated in EG-water (50:50) coolant. Evaluation of functional groups and organic compounds, the crystal structure of spinel ferrite, the size and morphology of nanoparticles, and the specific surface area, respectively, were carried out. For the developed magnetocaloric nanofluid, shear rate variation illustrates the non-Newtonian behavior of Bingham plastic. The results show that increasing the mass concentration of nanoparticles from 0.05 % to 0.8 % results in about 80 % increase in viscosity at 10 °C. Additionally, thermal conductivity has increased to a maximum of 9.4 % at 50 °C and is improved by increasing temperature.

Advancements in polyol synthesis: expanding chemical horizons and Néel temperature tuning of CoO nanoparticles

The polyol synthesis of CoO nanoparticles (NPs) is typically conducted by dissolving and heating cobalt acetate tetrahydrate and water in diethylene glycol (DEG). This process yields aggregates of approximately 100 nm made of partially aligned primary crystals. However, the synthesis demands careful temperature control to allow the nucleation of CoO while simultaneously preventing reduction, caused by the activity of DEG. This restriction hinders the flexibility to freely adjust synthesis conditions, impeding the ability to obtain particles with varied morpho-structural properties, which, in turn, directly impact chemical and physical attributes. In this context, the growth of CoO NPs in polyol was studied focusing on the effect of the polyol chain length and the synthesis temperature at two different water/cations ratios. During this investigation, we found that longer polyol chains remove the previous limits of the method, allowing the tuning of aggregate size (20–150 nm), shape (spherical-octahedral), and crystalline length (8–35 nm). Regarding the characterization, our focus revolved around investigating the magnetic properties inherent in the synthesized products. From this point of view, two pivotal findings emerged. Firstly, we identified small quantities of a layered hydroxide ferromagnetic intermediate, which acted as interference in our measurements. This intermediate exhibited magnetic properties consistent with features observed in other publications on CoO produced in systems compatible with the intermediate formation. Optimal synthetic conditions that prevent the impurity from forming were found. This resolution clarifies several ambiguities existing in literature about CoO low-temperature magnetic behavior. Secondly, a regular relationship of the NPs' TN with their crystallite size was found, allowing us to regulate TN over ~ 80 K. For the first time, a branching was found in this structure-dependent magnetic feature, with samples of spheroidal morphology consistently having lower magnetic temperatures, when compared to samples with faceted/octahedral shape, providing compelling evidence for a novel physical parameter influencing the TN of a material. These two findings contribute to the understanding of the fundamental properties of CoO and antiferromagnetic materials.

Novel Approach to Augment Thermal Conductivity of Dihybrid Nanofluids

In this experimental study, the copper oxide (CuO) nano–particle (NP) was mixed with a water/ethylene glycol hybrid base fluid to form a hybrid nano–fluid (HNF). Further, this HNF was mixed with a MgO nano–particle and also separately with a TiO2 nano–particle to form two different dihybrid nano–fluids (DHNFs). For the preparation of nano–fluids, two-step procedure was used. In all three cases, the volume fraction of the NP was 0.25, 0.5, 0.75, 1.0, and 1.25%. The thermal conductivity (TC) of HNF was measured with KD2 pro and compared with the DHNFs' at temperatures 26, 28, 30, and 32°C. It was inferred that the CuO/TiO2 nano–particle addition in the water/ethylene glycol hybrid base fluid resulted in an average of 0.8% rise in thermal conductivity at chosen temperatures and volume fraction. Also, the agglomeration due to the presence of CuO/MgO was a critical issue at higher volume fractions such as 0.75, 1, and 1.25%. The MgO nano–particle addition in the CuO nano–particle also resulted in a 0.6% increase in thermal conductivity at 0.25 and 0.5% volume fraction. The result was that in the CuO/MgO - water-ethylene glycol nano–fluid combination the TC was enhanced by 29.57% compared with CuO/water/ethylene glycol at a volume fraction increase of 0.5%. Also, it was noted that the nano–particles volume fraction has little effect on thermal conductivity improvement at higher proportion.

Dissipative heat transfer on MHD micropolar hybrid nanofluid flow through infinite parallel squeezing plates

The hybrid nanoparticles suspended in an ethylene glycol water mixture are modeled as micropolar nanofluids. Studying the properties of such a mixture through a squeezing channel is vital in heat exchangers and as a cooling agent in producing sheets out of molten solids. The study aims to regulate the heat transfer rate through a hybrid nanofluid of carbon nanotubes and ferrous oxide nanoparticles immersed in ethylene glycol water. The motion of the fluid and the heat transfer with the plates are studied through the Navier-Stokes equation and the first law of thermodynamics by assuming that the base fluid has micropolar fluid properties. Apart from the usual viscous dissipation, heat dissipation due to the fluid’s micropolar nature is vigorously studied by solving the governing equations through a shooting technique with Runge-Kutta 4th-order algorithm. The results of the current study are compared against the ones with earlier studies as exceptional cases, and are very close. It is noticed that an increase in the micropolar viscosity naturally lowers the momentum in the radial direction and, at the same time, it enhances the axial momentum due to squeezing phenomena. Further, an escalating behavior is noticed in both temperature and microrotation, with an increase in micropolar parameters due to the squeezing force.

Experimental study on single-phase heat transfer performance of internal helically finned tubes covering low Reynolds number in turbulent flow

ABSTRACT This paper experimentally investigated the heat transfer performance of two internal helically finned tubes covering low Reynolds number in turbulent flow. A water-ethylene glycol mixture flowed inside and R134a boiled outside. The numbers of fin, the helix angles, and the ratios of fin height to diameter for the two test tubes were 38 and 60, 60° and 45°, and 0.0534 and 0.0222, respectively. The experimental Reynolds number was lower to 5400, covering the critical Reynolds number Re cr for turbulent flow. The data was divided into good and poor linearity regions by the modified Wilson plot method, which was much suitable for this case than that the data was treated as one region. The j factors showed ascending trend for Re below Re cr and descending trend for Re above Re cr. Enhancement factors of friction factor or j factor of the test tubes increased with increasing Reynolds number and eventually approached at the maximum for the Reynolds number above Re cr. The test tubes exhibited maximum efficiency indexes of 2.1 and 1.88, indicating superior overall performance compared to the majority of existing tubes. By utilizing the experimental data, a correlation was established basing on the critical Reynolds number, resulting in over 96% of the predicted errors falling within the range of ± 8%. This study has the potential to provide valuable insights for industrial implementation and the advancement of general correlation development.

Optical and morphological studies of Titania nanotubes by varying anodization parameters

In this study, the self-organized Titania (TiO2) was created by anodizing pure titanium in a mixture of ethylene glycol, ammonium fluoride, and distilled water using an electrochemical cell. This study aims to examine how changes in anodization parameters impact the morphology and optical properties of Titania. The nanotubes achieved 10 μm length by applying less ammonium fluoride (NH4F) electrolytes. The energy dispersive X-ray spectroscopy (EDX) reveals that the prepared samples are essentially composed of TiO2. Mixed phases of rutile and anatase are obtained by increasing the annealing temperature from 360 to 480 ℃ and crystalline size seems to be reduced by increasing anodization potential, calculated by X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS) helps to identify the bandgap value and the minimum value attained at 2.56 eV without doping and the electron-hole recombination rates calculated through the intensity of photoluminescence (PL) analysis. Ultimately, the optimal values of the anodization parameters for the generation of the most effective sample are determined.

Experimental and theoretical investigation of an ionic liquid-based biphasic solvent for post-combustion CO2 Capture: Breaking through the “Trade-off” effect of viscosity and loading

To break through the “trade-off” effect of biphasic solvents between rich-phase viscosity and CO2 loading, we synthesized a novel ionic liquid (diethylenetriamine-3-hydroxypyridine, [DETA][3HPyr]) with multiple active sites and combined it with the organic solvent diethylene glycol monobutyl ether (DGME) and water to prepare a biphasic solvent for CO2 absorption, the best absorption condition was optimized. The results demonstrated that after absorption, the solvent transformed from homogeneous to biphasic with highly self-concentrated absorption products in the rich phase. The volume of the rich phase accounted for only 36.3 % of the total solvent, while its viscosity decreased significantly to 28.1 mPa·s, with a high blend absorption capacity of 2.67 mol·kg−1. The species of absorption product and absorption mechanism was investigated using 13C NMR. The stable presence of carbamic acid in the system was confirmed, contributing to enhanced absorption capacity. Density functional theory calculations revealed that DGME stabilized carbamic acid through intermolecular hydrogen bonding interactions, and highly polar ions generated during absorption and uneven charge distribution between ions dominated the phase-change process and increased the water content in the rich phase. Thermodynamic energy barrier calculation showed that the solvent effect of DGME reduced the Gibbs free energy barriers of proton transfer and facilitated reaction progress. 3IL4D3H exhibited excellent cyclic performance with low regeneration energy consumption at 1.77 GJ·t−1. This is the first work to revealing the intrinsic dynamics of carbamic acid formation, and provides a new perspective for the phase-change mechanism of ionic liquid-based biphasic solvent.

Determining The Crystallite Size of TiO2/EG-Water XRD Data Using the Scherrer Equation

&lt;p class="Abstract"&gt;X-ray diffraction (XRD) data and the Scherrer equation were utilized to analyze the crystallite Size of titanium dioxide (TiO&lt;sub&gt;2&lt;/sub&gt;) in a solution of ethylene glycol (EG) and distilled water. The XRD analysis was conducted using a Rigaku Miniflex 600 instrument with an X-ray wavelength of approximately 0.15046 nm. The examination yielded the full-width half maximum (FWHM), which was subsequently examined using the Scherrer equation. This experiment employed TiO&lt;sub&gt;2&lt;/sub&gt; with a purity level of 99.8% and a crystal Size of 30 nm. The analysis revealed that the average crystallite Size of TiO&lt;sub&gt;2&lt;/sub&gt; in the sample is 19.45 nm, with the highest measurement at about 30.38 nm. The Spearman correlation equation was employed to validate the outcomes. The Spearman's correlation coefficient between the FWHM variable and the crystallite Size of TiO&lt;sub&gt;2&lt;/sub&gt; nanoparticles is -0.958. These findings shed light on the crystal structure of TiO&lt;sub&gt;2&lt;/sub&gt; under these conditions. These findings lend support to the use of TiO&lt;sub&gt;2&lt;/sub&gt; in a variety of nanotechnology applications. However, more research is needed to understand fully how crystallite-Size TiO&lt;sub&gt;2&lt;/sub&gt; nanoparticles work in different settings and to find the best ways to prepare samples, including understanding the specific phase and how it affects the stability of fluids. This research contributes significantly to the understanding of the properties of TiO&lt;sub&gt;2&lt;/sub&gt; in a solution of distilled water and EG, as well as to the characterization of nanomaterials, with particular emphasis on issue 9 of the SDGS Goal concerning industry, innovation, and infrastructure.&lt;/p&gt;

Durable slippery liquid-infused porous surfaces for effective corrosion protection of aluminum alloy in ethylene glycol-water solutions

Aluminum (Al) alloys are extensively utilized in liquid-cooling heat dissipation systems owing to their superior strength-to-weight performance, ease of processing, and high thermal conductivity. However, they are susceptible to corrosion in the cooling medium, such as ethylene glycol-water solutions. This study presents a straightforward and cost-effective method to create a slippery liquid-infused porous surface (SLIPS) designed to effectively prevent corrosion of the 6061 Al alloy in ethylene glycol-water solutions. Micro/nano hierarchical structures were achieved on the SLIPS through plasma electrolytic oxidation and hydrothermal treatment. Following the modification of low-surface-energy materials and the infusion of silicone oil, the SLIPS exhibited an outstanding slippery property, allowing ethylene glycol-water droplets to effortlessly slide down the inclined surface at an angle of 1.1°. Additionally, the SLIPS demonstrated remarkable anti-corrosion performance against ethylene glycol-water solutions, with a minimum corrosion current density (Icorr) of 2.4 × 10−10 A·cm−2. Crucially, long-term immersion test results on corrosion resistance revealed that the SLIPS provided reliable corrosion protection for the 6061 Al alloy, exhibiting an Icorr increased by 4 orders of magnitude compared to a smooth substrate. These findings hold significant potential for advancing the widespread application of SLIPS in liquid-cooling heat dissipation systems.

Heat transfer analysis in hybrid nano-composite flow in a stretchable convergent/divergent channel in the preaence of Darcy-Forchheimer law and Lorentz force

The hybrid nano-composite fluid transportation in Jaffery-Hemal flow (JHF) has important uses in various technologies, like converging dies, hydrology, automobiles, etc. Such significant applications motivated us to work on the current problem. Therefore, the purpose of the current work is to inspect the energy efficiency analysis of hybrid nanofluids via convergent/divergent channels using porous space. The hybrid nanofluid consists of polyethylene glycol water, nanoparticles ZrO2 and MgO. To understand the porosity features, the Darcy-Forchheimer law is used. Solar radiation is considered for a more comprehensive analysis of the thermal field. The strong ODEs are obtained using a suitable similarity transformation. The NDSolve technique is used to simulate numerical results, which are then compared with previous published results. Plots and tables are used to report physical investigations of the related parameters. For higher solid volume fractions, the divergent channel’s velocity drops. Whereas it increases for a convergent channel. In the presence of variables, Eckert number, and porosity parameter, skin friction increases in divergent channels and decreases in convergent channels for both nanofluids and hybrid nanofluids. Furthermore, it is noticed that hybrid nanocomposite has more dominant features than nanocomposite for both scenarios of narrowing/expanding channels.

Characterization of TiO2 nanoparticles for nanomaterial applications: Crystallite size, microstrain and phase analysis using multiple techniques

This study aimed to verify the suitability of TiO2 nanoparticles as nanomaterials in terms of crystallite size, microstrain and phase. The TiO2 nanoparticles were tested experimentally in suspensions of mono ethylene glycol and distilled water (MEG-DW) at ratios of 10:90, 25:75, and 40:60. The nanoparticles were dispersed in the base liquid via a two-step process, resulting in the formation of TiO2-3%/MEG-10, TiO2-3%/MEG-25, and TiO2-3%/MEG-40 nanofluids. The results revealed average crystallite sizes of approximately 20.10, 22.10, and 39.6 nm for the three nanofluid samples, as determined by the Scherrer equation, Williamson–Hall (W–H) plot, and TEM-ImageJ software. These results confirm that the TiO2 nanoparticles meet the nanomaterial criteria with a sub-100 nm size. The microstrain analysis yielded values of 0.000020, 0.000299, and 0.001386 for the three samples and further investigation confirmed the presence of rutile. The high-temperature stability of the rutile phase makes the TiO2 nanofluids suitable for use in industrial heating systems.

Numerical investigation of thermal and hydraulic characteristics in porous pin fin heat sinks using single phase nanofluids

This study aims to numerically investigate the thermal performance of porous square pin-fin heat sinks, considering three different configurations: inline, staggered, and 45° inline. Six different nanofluids, comprising CuO, Al2O3, and TiO2 nanoparticles dispersed in water and water–ethylene glycol mixtures at two volume fractions (φ = 0.5 % and 2 %), are employed as coolants. The impact of porosity on the thermal and fluidic behavior is also examined for the CuO–Water nanofluid (φ = 2 %) at porosity values of 40 %, 50 %, and 60 %. The commercial CFD code: Ansys Fluent 2020R1 is utilized for this numerical analysis and the results are compared to relevant experimental works for validation. The effects of heat sink geometry, nanofluid type, and porosity on heat transfer performance are systematically analyzed. The results show that the 45° inline configuration of the square pin-fin heat sink exhibits superior heat transfer enhancement compared to both the inline and staggered configurations. The use of nanofluids as coolants significantly improves the thermal performance compared to conventional fluids, with CuO–Water nanofluid demonstrating the most promising results. This comprehensive analysis provides valuable insights for the design optimization of high-performance cooling systems for electronic devices.

Heat transfer scrutiny in EMHD ternary hybrid nanofluid flow between convergent/divergent channels with stretchable walls

ABSTRACT The main interest of the existing work is the numerical and analytical exploration of heat transference on MHD Jeffery-Hamel flowing of a ternary hybrid nanofluid with an external magnetized force and electrical field (EMHD). The two walls of the system are also taken to be stretchable (shrinkable). Mixture base fluid (ethylene glycol-water 50%–50%) hybrid nanofluid containing MoS2, Al2O3, and TiO2 as the nanoparticles are contemplated. The modeled partial differential equations were converted to nonlinearly ordinary differential equations by applying the similarity transformations and resolved analytically by utilizing the Duan – Rach Approach (DRA). The present results in particular cases are compared to results obtained by the HAM (homotopy analysis methodology)-based Mathematica BVPh 2.0 code and by the Runge-Kutta Fehlberg 4th–5th order (RKF-45) for validation. The effect of varied factors on non-dimensional rapidity, temperature profiles, frictional force factor, and Nusselt quantity has been examined and explained via tabular and graphical outcomes. Certainly, new modeling and reliable analytic treatment via the DRA approach for the ternary hybrid nanofluid is a sizable accomplishment of the current analysis.

Tribocorrosion behavior of GCr15 steel in water–glycol fire-resistant hydraulic fluids (HFC) containing seawater

With the development of deep-sea exploration technology, the technology of fire-retardant hydraulic fluid (HFC) has played an important role in the power transmission of exploration equipment. However, the mechanism of the influence of seawater content on the tribocorrosion behavior of HFC remains unclear. In this study, the effects of different seawater contents on the tribological and corrosive properties of HFC were systematically investigated. The results showed that when the seawater concentration exceeds 30 wt%, a soft Mg-containing reaction film is formed in the friction contact area owing to seawater corrosion, thus effectively improving the sintering load and wear resistance to some extent. By contrast, with increasing seawater concentration, the lubricity declines, the wear intensifies, and the extreme pressure characteristics decrease significantly. The comparative analysis shows that the composition of the wear and corrosion reaction films significantly differs under high-concentration seawater conditions, which is also a key factor affecting the friction and corrosion behavior of HFC. This study provides a direction for the research and development of wear- and corrosion-resistant materials and coatings on the surface of deep-sea exploration equipment.

Amino acid-based ionic liquids as water-ethylene glycol additives towards superior lubricity and corrosion resistance

Two novel amino acid-based ionic liquids (AAILs) were synthesized and their tribological properties as water-ethylene glycol (W-EG) lubricant additives were investigated. The addition of 1 wt% of both AAILs to W-EG can significantly enhance the anti-corrosion, friction-reducing and anti-wear properties of the lubricants. Compared to W-EG, the coefficient of friction and wear volume are reduced by about 50% and 75%, respectively. The physical adsorption film and the tribochemical reaction film derived from AAILs collectively establish a protective barrier at the friction interface, endowing the lubricants with superior lubricity and load-carrying capacity. These two sulfur-free and halogen-free AAILs are promising for application in metal working fluids and hydraulic fluids.

Heat transfer performance study of Cu-ethanol/ethylene glycol/propylene glycol-water nanofluids in a wavy-walled tube heat exchanger

With the rapid consumption of nonrenewable energy sources, improving the heat transfer efficiency of conventional fixed tube plate heat exchangers, optimizing their structure, and finding more efficient coolants have become popular topics. In this paper, the cooling effect of ethanol/ethylene glycol/propylene glycol-water solution with a mass fraction of 50 % in a wavy-walled tube heat exchanger was investigated, while Cu nanoparticles with volume fractions of 1.5 % and 3.0 % were added to the cold working mass to form three different nanofluids. The effects of the three nanofluids at different volume fractions on the heat transfer performance of the wavy-walled tube heat exchanger were analyzed with numerical simulations, while the microscopic mechanism of the enhanced thermal conductivity of the nanofluids was investigated using molecular dynamics simulations. The results showed that the thermal conductivity of the nanofluids was greatly enhanced due to the formation of adsorption layers with different properties on the nanoparticle surfaces, and the Cu–ethylene glycol-water nanofluid showed the largest increase in thermal conductivity among the three nanofluids. It was also found that the shell-side pressure drop, convective heat transfer coefficient, and heat exchange quantity of the nanofluid in the wavy-walled tube heat exchanger significantly increased with an increase of volume fraction. The comprehensive heat transfer performance of the three nanofluids was found to be better compared to the base fluid. Cu-ethanol/EG/PG-water nanofluid with a volume fraction of 3.0 % increased the PEC of the heat exchanger by 10.4 %, 19.8 % and 27.6 %, respectively, at a volume flow rate of 1.53 m3/h. Therefore, the Cu-propylene glycol-water nanofluid had the best comprehensive heat transfer performance. Cu-ethanol-water nanofluid volume fraction of 3.0 % reaches a maximum PEC value of about 3.12 at Qv near about 2.0 m3/h, and Cu-EG-water nanofluid volume fraction of 3.0 % has a peak PEC value of about 4.07 at Qv of near about 2.0 m3/h. Therefore, the Cu-ethanol-water and Cu-ethylene glycol-water nanofluids are the optimal solutions for the combined heat transfer performance within the study.