Water-based Fluids Research Articles

Viscosity Anomalies of Magnetic Fluid Stabilized by a Double Layer of Surfactant in Water

Purpose to study the temperature dependence of the viscosity of a water-based magnetic fluid.Method. Consists of measuring the dynamic viscosity of a magnetic fluid based on cobalt ferrite particles stabilized in water by a double layer of surfactant. Lauric acid (first layer) and a mixture of lauric acid and sodium dodecyl sulfate (second layer) were used as a stabilizer. Measurements were performed using a Brookfield DV-II+Pro rotational viscometer equipped with a coaxial cylinder system. The measuring system of the viscometer was thermostated using a KRIO-VT-12-1 thermostat.Results. The temperature dependences of dynamic viscosity were measured for three samples of magnetic fluid based on cobalt ferrite particles of various concentrations in the temperature range 0–90C°. The obtained temperature dependences of viscosity are radically different from the temperature dependences both predicted by known theories and experimentally observed for kerosene-based magnetic fluids. According to well-known theoretical models, the ratio of the viscosity of the magnetic fluid to the viscosity of the base medium is a certain universal function of particle concentration. Different models offer different types of this feature. But it clearly follows from them that the viscosity ratio should not depend on temperature. For magnetic fluids based on kerosene, it has been experimentally established that its relative viscosity decreases with increasing temperature. However, according to the results obtained, the relative viscosity of a water-based magnetic fluid does not decrease with increasing temperature, but increases significantly. That is, the viscosity of a water-based magnetic fluid decreases more slowly with increasing temperature than the viscosity of water.Conclusion. The observed dependencies completely contradict the known patterns, both theoretical and experimentally established for kerosene-based magnetic fluids. The results obtained may be useful for the further development of the theory of aqueous colloidal solutions with particle stabilization by a double layer of surfactants.

Water:Ethylene Glycol Properties Alteration Upon Dispersion Of Al2O3 and SiO2 Nanoparticles

Proton exchange membrane fuel cell (PEMFC) seems to be a popular option as a green energy carrier due to its high efficiency and pollutant-free operation. However, the slight temperature difference between the working temperature and surroundings requires innovation in cooling strategy. Active thermal management strategy is limited due to the larger space requirement. Alternatively, utilizing nanofluids as coolant as the passive cooling strategy tends to be a viable quick fix. In this research, thermophysical properties of Al₂O₃:SiO₂ hybrid nanofluids in the base fluid of water: Ethylene Glycol (EG) were discussed comprehensively concerning alterations made in thermal conductivity, dynamic viscosity, and electrical conductivity properties. There were four mixture ratios of 0.5% volume concentration of hybrid nanofluids considered ranging from 10:90, 30:70, 50:50, and 70:30 Al₂O₃:SiO₂. Upon completion of the study, there is an improvement of 9.8% shown in 10:90 Al₂O₃:SiO₂ hybrid nanofluids for thermal conductivity measured at 60C in comparison to the base fluid. Meanwhile, 10:90 Al₂O₃:SiO₂ hybrid nanofluids are also favorable with the lowest values of viscosity as compared to other mixture ratios resulting in lower parasitic loss. Electrical conductivity on the other hand also showed an increment in 10:90 Al₂O₃:SiO₂ hybrid nanofluids as compared to base fluid and other mixture ratios.

Investigation of forced convection of a novel hybrid nanofluid containing NEPCM in a square microchannel: Application of single-phase and Eulerian-Eulerian two-phase models

In the present study, laminar forced convection flow and heat transfer of novel hybrid nanofluid of Al 2 O 3 -n-octadecane/water through a horizontal microchannel under a constant wall heat flux condition are investigated. N-octadecane is regarded as a nano-encapsulated phase change material (NEPCM). Simulations are performed utilizing single-phase and Eulerian-Eulerian two-phase models. Governing equations are discretized by finite volume method and then solved using SIMPLE algorithm. Effects of nanoparticles volume fraction ( φ ), Reynolds number ( Re ), and melting range ( T mr ) on thermal and hydrodynamic parameters of hybrid nanofluid are evaluated. It is shown that predictions by Eulerian-Eulerian approach are more accurate than those by single-phase approach when compared to available experimental data. Addition of Al 2 O 3 and n-octadecane nanoparticles to water-based fluid leads to a reduction in fluid and wall temperatures, which is intensified at higher φ and Re . Also, these nanoparticles do not have a significant effect on hydrodynamic development of flow, while they delay its thermal development. NEPCM with a higher T mr only slightly improves thermal performance of hybrid nanofluid, which is more noticeable in single-phase procedure. Total efficiency of hybrid nanofluid ( η hnf ) is amplified by raising φ for both approaches. This augmentation is more evident in Eulerian-Eulerian model due to better thermal and hydrodynamic performances. Maximum increases in η hnf concerning single-phase and Eulerian-Eulerian models are 27% and 60%, respectively, occurring at φ Al 2 O 3 = 1 % and φ n ‐ octadecane = 10 % . Therefore, this type of hybrid nanofluids, because of its enhanced thermo-physical properties, can be considered as a suitable candidate for thermal energy storage, heat transfer, and renewable energy applications.

Water Based Mn-Zn Magnetic Fluid Heat Dissipation Capacity Testing Platform

Manganese zinc magnetic fluid is a temperature sensitive magnetic fluid that can regulate its flow behavior using temperature and magnetic fields. However, there is currently no testing platform for evaluating the heat dissipation ability of this magnetic fluid working fluid by coupling temperature and magnetic fields. This article establishes two experimental testing platforms for applying magnetic fields, namely a circulating pipeline and a temperature equalization plate. Compared with deionized water, evaluate the average temperature and heat dissipation ability of water-based manganese zinc magnetic fluid. The test results show that the heat dissipation start time of the manganese zinc magnetic fluid loop pipe is better than that of deionized water. Under the action of magnetic field (500Gs), the average temperature of the circulating pipeline decreases by 7.2% (heat source power 15W); Under the action of a magnetic field (3000Gs), the thermal resistance of the homogenizing plate (filled with 48% water-based manganese zinc magnetic fluid) decreases by about 16.7% (heat source power 140W). The water-based manganese zinc magnetic fluid working fluid exhibits better heat transfer performance than the deionized water working fluid under high heat source power. The experimental results prove that the designed water-based manganese zinc magnetic fluid working fluid heat dissipation capacity testing platform has reliable experimental quantification results.

Ethylene Glycol-water Based Graphene Oxide Nanofluid as Corrosion Inhibitor in Automotive Radiator

A rapid cooling process is essential to maintain an optimal working temperature in a vehicle, which directly impacts its efficiency. Corrosion is a persistent and inevitable damage in cooling systems that use water-based fluids. The current challenge is to explore water-based fluids that not only exhibit excellent corrosion resistance but also possess superior heat conduction properties to improve vehicle efficiency. This study investigated the incorporation of Graphene Oxide, renowned for its corrosion inhibition properties, into ethylene glycol/water solution to assess its protective efficacy on Al6061 material. A series of analytical methods, including Optical Emission Spectroscopy (OES), pH, conductivity, Fourier-Transform Infrared Spectroscopy (FTIR), and polarization techniques, are used to evaluate the corrosion inhibition performance of graphene oxide at various concentrations and under different ambient temperatures. The results showed a decrease in pH value and conductivity with increasing concentration of graphene oxide. FTIR analysis confirmed the formation of a protective layer on the surface of Al6061. Corrosion rate assessment was performed on Al6061 samples immersed in ethylene glycol/water mixture with graphene oxide concentrations of 0, 0.03%, 0.05%, and 0.10%. There was a significant decrease in corrosion rate with the addition of graphene oxide to the cooling system: at 30°C, the rate decreased to 4.620, 3.308, 2.565, and 1.006 mpy; at 40°C, up to 4,728, 2,541, 1,503, and 1,270 mpy; and at 50°C, up to 5.629, 1.146, 2.947, and 1.441 mpy, corresponding graphene oxide concentrations of 0.03%, 0.05%, and 0.1%, respectively. Experimental data confirmed that graphene oxide effectively reduces the corrosion rate of Al6061 in ethylene glycol/water mixtures. The study concluded that the use of graphene oxide as a corrosion inhibitor markedly improved the resistance and performance of Al6061 in ethylene glycol/water, with graphene oxide contributing to this protective mechanism through the process of physisorption.

Combined effect of the magnetic field, orientation, and filling ratio on cylindrical pulsating heat pipe using distilled water and distilled water/Fe3O4 nanofluid

To investigate the effect of the magnetic field, a pulsating heat pipe was made in the shape of a cylinder and Fe3O4 nanoparticles (%0.1 wt) were used with the base fluid of distilled water as the working fluid. (Tetramethyl ammonium hydroxide) TMAH surfactant was used as a stabilizer. To investigate the effect of gravity on the performance of the pipe, the device was tested at different angles from zero to 90 degrees. In this research, the effect of different variables, including the type of working fluid (distilled water vs. nanofluid), filling ratio, slope, and amount of heat input to the evaporator (30–300 W), in two different states, once without the influence of the magnetic field and once again with the application of a magnetic field was investigated. The results of the tests showed that the performance of the device at 50 % filling ratio is better than 60 % filling ratio. The use of nanoparticles improved the performance of the device. Inclining the device increases the thermal resistance so that the device performs poorly in the horizontal mode in all modes except when it is under the influence of a magnetic field. The use of nanofluid as well as the application of a magnetic field makes the start-up time of the device decrease by 37 % and 30 %, respectively, compared to distilled water. The temperature of the start of fluctuations also decreases by 24 % and 32 %, respectively.

Analysis of Selected Fiber-Rich Agricultural Waste as Water-Based Drilling Mud Fluid Loss Control Additives

For a drilling operation to be successful, the drilling fluid performance must be optimized. This research study the use of degradable agricultural waste namely cowpea skin powder (CSP), sugarcane rind powder (SRP) and yam bark powder (YP) as additives for fluid loss control. The elemental composition of these food wastes was determined using SEM. Proximate analysis was performed to investigate the content of moisture, ash, nitrogen, protein, volatile matter, fixed carbon, bulk density, specific gravity and pH. The local additives were used at 1% (5grams), 3% (10grams), 4% (15grams) and 5% (20grams) each. For CSP fluid loss increased at 5g and 10g (1% and 3%), by 14% and 9% respectively, at 15g and 10.6g, fluid loss decreased by 33% and 36% respectively. Using SRP of 5g increased fluid loss by 12% but there was decrease in fluid loss with 10g, 15g and 2g in these percentages; 14%, 33% and 37% respectively. YP resulted in fluid loss at 5g giving 1.5% loss, 12% loss with 10grams, 16% fluid loss with 15 grams and 33% filtrate loss with 20grams. Overall, SRP showed best fluid loss performance with 20grams (5%), resulting in 37% fluid loss decrease followed by Yam bark powder at 20grams with fluid loss performance of 33%. The least performance was by CSP at 5grams (3%) that increased the filtrate loss by 14%.

Antibacterial Surface Protection using Electrical Discharge Machining with Zinc Tool Electrode for Medical Devices

Electrical discharge machining (EDM), widely used to fabricate medical devices, is applicable for antibacterial surface protection. Silver, transferred from tool electrode or powder suspended in the dielectric to the modified layer during the EDM process, significantly enhanced antibacterial properties of the modified surface. However, bacterial resistance to silver, which was widespread in clinical, still posed challenges for the modified surfaces containing silver.Zinc, owing to its strong antibacterial effects and no challenge related to Zn-resistant bacteria hitherto reported in clinical, was therefore used as tool electrode material to modify Ti6Al4V surfaces during the EDM process. Discharge energies up to 170 µJ with different polarities were applied in the EDM milling process using deionized water-based dielectric fluid. Results show that discharge energy and polarity play a vital role in chemical composition and roughness of the modified surfaces as well as material removal rate and tool wear rate. The surfaces containing zinc contents up to 28 % can be generated. The use of a low energy generates zinc-rich surfaces with less micro-cracks. The EDM process using zinc tool electrode shows a promising potential for antibacterial surface modification of medical devices.

Study of a small molecule gel fracturing fluid and its in situ conversion into an efficient oil displacement agent

Viscoelastic surfactants (VESs) are critical components of water-based fracturing fluids.

The TLBO algorithm-based optimal heat transfer parameters prediction of Al2O3 water nanofluids in variable pitch corrugated tube heat exchanger

This study investigated an Al2O3 nanofluid water-based tube heat exchanger fitted with a corrugated copper tube under laminar flow conditions. This study is carried out to observe the heat transfer rate within the heat exchanger. The effect of nanoparticle concentrations, the flow rate of the working fluid, and the corrugated tube pitch on the heat exchanger efficiency were analysed. The results show that when Al2O3 water nanofluids are sandwiched between corrugated copper tubes, the heat transfer rate is significantly enhanced compared to the smooth tubes. Nanofluids of Al2O3 were prepared with concentrations of 0.25%, 0.5%, and 1% in deionised water. Corrugated tubes with 25 mm, 20 mm, and 18 mm pitches were fabricated for this investigation. The deionised water and Al2O3 nanofluid-flow rates were maintained at 0.1 m3 per hours, 0.15 m3 per hours, and 0.2 m3 per hours, respectively. Results showed that Al2O3 nanofluids improved the heat transfer rate related to water-based fluids. The highest heat transfer occurred in the 18 mm pitch corrugated copper tube in which 1% nanofluid volume concentration was used as the heat transfer medium. It is observed that the heat exchanger containing corrugated copper tubes with pitch 17.88 mm having 0.98 vol.% of Al2O3 nanofluids, flowing at 0.198 m3 per hour, enhances the heat transfer rate between the working fluids.

Numerical Study of the Thermal and Hydraulic Characteristics of the SiO2–Water Nanofluid through a Backward-Facing Step

The work of this paper is devoted to the two-dimensional numerical investigation of the turbulent forced convection through backward-facing step. Two cases are taken into account. For the first, the bottom wall is smooth; but for the second case, it is corrugated with a triangular base containing ten corrugations. A uniform heat flux is imposed on the bottom wall. A flow of a nanofluid consisting of silicon dioxide SiO2 nanoparticles dispersed in a base fluid (water) flows through this step.The flow equations were discretized by the finite volume method. For modeling turbulence, the K-ɛ-RNG model was applied to analyze Reynolds number effect, the volume fraction and the size of the particle. Numerical simulations were conducted for various Reynolds between 10,000 and 40,000; volume fractions of nanoparticles which vary from 0 to 5% and particle diameter dp equal to 30; 50 and 70 nm. We noted that the obtained findings are in good conformity with those of the literature.

Entropy generation analysis for convective flow of aqua Ag-CuO hybrid nanofluid adjacent to a warmed down-pointing rotating vertical cone

PurposeThis paper aims to study numerically the flow, heat transfer, and entropy generation of aqueous copper oxide-silver hybrid nanofluid over a down-pointing rotating vertical cone, with linear surface temperature (LST) and linear surface heat flux (LSHF), in the presence of a cross-magnetic field. In industrial applications, such as oil and gas plants, food industries, steel factories and nuclear packages, the real bodies may contain nonorthogonal walls and variable cross-section three-dimensional forms which this issue can clarify the importance of selective geometry in the present research.Design/methodology/approachThe mass-based scheme is accomplished for the simulation, and the entropy generation and Bejan number will be analyzed in conjunction with the aforementioned model. It has been hypothesized that two types of boundary conditions (LST and LSHF) as well as five nanoparticle shapes (sphere, brick, cylinder, platelet and disk) present a collection of crucial results. The overseeing PDEs are changed over completely to the dimensionless ODEs, and these are solved by Runge–Kutta–Fehlberg approach combined with a shooting methodology for certain values of physical parameters.FindingsSubsequent to the fantastic compromise of the computational outcomes with past reports, the outcomes are introduced to conduct the investigation of the hydrodynamics/thermal boundary layers, the skin friction and the Nusselt number, as well as entropy generation and Bejan number. A state of hybrid nanofluid, which exhibits a remarkable increase in heat transfer in comparison to the states of mono-nanofluid and regular fluid, has been found to have the highest Nusselt number; however, the skin friction values should always be taken into account and managed. The entropy generation improves with the mass of the second nanoparticle (silver), while the opposite pattern is exhibited for the Bejan number. Furthermore, the lowest value of entropy generation number belongs to the cylindrical shape of nanoparticles in the LST case. In final, a significant accomplishment of the current study is the accurate output of the mass-based scheme for an entropy analysis problem.Originality/valueTo the best of the authors’ knowledge, for the first time, in this study, a new development of natural convective flow of a hybrid nanofluid about the warmed (LST and LSHF) and down-pointing rotating vertical cone by the mass-based algorithm has been presented. The applied methodology considers the masses of base fluid (water) and nanoparticles (Ag and CuO) as an alternative to the first and second nanoparticles volume fraction. Indeed, the combination use of the Tiwari–Das nanofluid model and the mass-based hybridity algorithm for the entropy generation analysis can be the main novelty of this work.

The Effect of Graphene Oxide Biomass as Filtration Loss Control Agent of Water-Based Mud Fluid

The Effect of Graphene Oxide Biomass as Filtration Loss Control Agent of Water-Based Mud Fluid

Mixed convection of two layers with radiative electro-magnetohydrodynamics nanofluid flow in vertical enclosure

Mixed convection flow of two layers nanofluid in a vertical enclosure is studied. The channel consists of two regions. Region I is electrically conducting while Region II is electrically non-conducting. Region I is filled with base fluid water with copper oxides nanoparticles and Region II is filled with base fluid kerosene oil with iron oxides. The simultaneous effects of electro-magnetohydrodynamics and Grashof number are also taken into account. The governing flow problem consists of nonlinear coupled differential equations which is tackled using analytical technique. Analytical results have been obtained by the homotopy analysis method (HAM). The results for the leading parameters, such as the Hartmann numbers, Grashof numbers, ratio of viscosities, width ratio, volume fraction of nanoparticles, and the ratio of thermal conductivities for three different electric field scenarios under heat generation/absorption were examined. It is found that the effect of the negative electric load parameter assists the flow while the effect of the positive electric load parameter opposes the flow as compared to the case when the electric load parameter is zero. All outcomes for significant parameters on velocity and temperature are discussed graphically.

Low-temperature gel breaking fracturing fluid for marine hydrate reservoir fracturing and its effect on phase equilibrium of methane hydrates

Hydraulic fracturing has been proven useful for improving the gas production efficiency of low-permeability hydrate reservoirs. However, no specific fracturing fluid system exists for marine hydrate reservoirs. Applying conventional water-based fracturing fluids in low-temperature (<293.2 K) marine hydrate reservoirs can lead to difficulties in gel-breaking and hydrate instability caused by external additives. In this study, we developed two water-based fracturing fluid systems that exhibited good gel-breaking performance at low temperatures (278.2–288.2 K), one comprising ammonium persulfate (APS), ferrous sulfate (FeSO4), and citric acid (CA), the other APS and triethanolamine (TEA). In addition, we investigated the influence of crosslinking and gel-breaking reactions of the fracturing fluids on the methane hydrate phase equilibrium. The breaking time of the APS-FeSO4-CA system at 278.2K, 283.2K, and 288.2K was 30 min, 75 min, and 120 min respectively. On the other hand, the APS-TEA system accomplished the same task in 3 h, 6 h, and 10 h respectively. Furthermore, methane hydrate phase-equilibrium data showed that the fracturing fluid's three states, base fluid (BF), fracturing fluid gel (FFG), and gel-breaking liquid (GBL), all exerted an inhibitory effect on the phase equilibrium, with the hydrate suppression temperature (ΔT) ranging from 0.4 to 1.0 K. The differences in their inhibitory effect were primarily related to the micromorphology of the hydroxypropyl guar gum (HPG) molecules and the number of active hydroxyl (-OH) groups in the solution. Cryo-scanning electron microscopy (SEM) measurements revealed that the micromorphology of HPG in BF, FFG, and GBL transformed from regular ribbon-like structures to 3-D network structures and then to hole-containing, short ribbon-like structures. FFG formed a regular 3-D network structure after adding crosslinking agents to the BF. The ΔT values reversed from FFG < BF to FFG > BF when the HPG concentration increased from 0.3 wt% to 0.5 wt%, possibly due to the difference in the HPG molecules' water adsorption capacity before and after crosslinking. The broken HPG molecules with OH− groups in the solution were transformed into residues after gel-breaking, decreasing the GBL's inhibitory effect. Therefore, our results indicated that micromorphology variations could cause differences in the HPG molecules' water adsorption capacity, ultimately leading to ΔT differences. Based on our findings, the gel-breaking fracturing fluid systems we developed demonstrated potential for optimizing hydraulic fracturing in marine hydrate reservoirs.

FRACTURING LIQUID DESIGN AND ECONOMIC ANALYSIS FOR LOW PERMEABILITY AND HIGH TEMPERATURE

Mirabelle 01 M01 well is a developed-stage well which has undergone drilling since February 2020 until May 3th 2020. It has 13000 ft depth and dominated with sandstone layers and some shaly inserts. This well is a high temperature (300 F), low permeability (0.5-5 mD) and porosity well which casues hydraulic fracturing should be done in this well. Aim: to carry out fluid fracturing design analysis by considering additional materials and economics. The perforation in this well divided into 2 perforations, first perforation has been 297 ft long and located at 12143 ft-12440 ft of well depth. The second perforation has been 45 ft in length and is located at 12,730 ft-12,685 ft of well depth. Payzone of this well is dominated by sandstone which is determined from the low gamma ray data. This Mirabelle 01 M01 well has high resistivity due to the resistivity log. Water mix used for the formation is a neutral water mix but still has several negative ions with corrosive properties such as SO42- and Cl-. Acid inhibitors are needed to remove these ions and prevent corrosive to be happened. Scale inhibitors are also needed to be added to prevent scale formation caused by Mg2+ ions which are contained in the mix water. From the average pressure calculation, the closure pressure was found about 7914.67 psi. The young modulus found from 8-10 Mpsi which indicates that the formation has high stiffness. The base of the fracturing fluid used is low price water-base fluid with guar gum polymer which can produce hydroxypropilguar (HPG) that don't ruin the formation even if the formation is in the high temperature. Borate ions are used to be crosslinker agents that binds metal ions with polymers. To split polymers molecules, sodium salt from the peroxydisulphate is used to be the gel breaker.

Numerical Simulation for Cooling of Integrated Toroidal Octagonal Inductor Using Nanofluid in a Microchannel Heat Sink

This paper presents a comprehensive numerical simulation study focused on the cooling of integrated toroidal octagonal inductor using nanofluids within a microchannel heat sink. The investigation utilizes COMSOL Multiphysics 6.0 integrated with the Fluid Flow and Conjugate Heat Transfer Module. The primary objective is to explore and understand fluid flow and heat transfer characteristics within the integrated inductor. The study involves testing three distinct fluids, water, CuO-water nanofluid, and Al2O3-water nanofluid, under laminar flow conditions within microchannels. The choice of fluid plays a significant role in heat transfer, interacting with the microchannel geometry to optimize performance. Three-dimensional computational fluid dynamics (CFD) models are meticulously developed; focusing on toroidal inductors equipped with micro pin fins heat sinks. The study commences by detailing the geometry of the micro coil and the integrated heat sink. The simulation encompasses a mathematical model that captures the intricate interplay between the governing Navier-Stokes equations for fluid dynamics and the heat transfer equations within the integrated inductor. As φ increases, temperature, viscosity, and pressure decrease. CuO-water and Al2O3-water nanofluids play a significant role in influencing laminar flow and key thermal parameters in the toroidal inductor. These nanofluids, which consist of base fluids (water) with dispersed nanoparticles (CuO or Al2O3), are employed as cooling agents to enhance heat transfer. The presence of nanoparticles in the fluid alters its thermal properties, leading to changes in the flow dynamics and overall heat dissipation within the toroidal inductor.The laminar flow characteristics are affected by the nanofluid's viscosity, density, and thermal conductivity. Additionally, the Nusselt number, Reynolds number, and thermal resistance are key thermal parameters that reflect the performance of the cooling system. The nanofluid's influence on these parameters is crucial for understanding and optimizing the thermal management of the integrated toroidal inductor. The enhancement of heat dissipation in the toroidal inductor is achieved through improved thermal properties of the nanofluid. Higher nanoparticle concentrations result in better heat transfer rates, leading to lower temperatures in the toroidal inductor. This, in turn, improves the overall efficiency and performance of the cooling system. The viscosity of the nanofluid is influenced by the presence of nanoparticles. The pressure within the microchannels is also affected by the nanoparticle concentration. An increase in φ can lead to changes in pressure drop along the microchannels. Understanding these variations is crucial for designing an effective cooling system.

Fe3+-crosslinked alkyl phosphate ester as thickener for oil-based fracturing fluids

To reduce damage to the formation of water locking and water sensitivity causing poor fracturing effect during the fracturing by water-based fracturing fluid in shale oil and gas reservoirs, the oil-based fracturing fluid as anhydrous fracturing fluid were prepared with dialkyl phosphate (PO(OH)(OR)(OR’)) as gelling agent, complexed iron ion solution as activating agent, n-hexane or kerosene as base fluid. The dialkyl phosphate was synthesized by two-step processes. In the first step, the optimal reaction conditions for preparing monoalkyl phosphate intermediate were the reaction time 5 h, reaction temperature 85 °C, molar ratio of triethyl phosphate to phosphorus pentoxide 3.4:1. In the second step, the optimal synthesis conditions for preparing dialkyl phosphate esters were the reaction time 4 h, reaction temperature 80 °C, molar ratio of the intermediate monoalkyl phosphate esters to the mixed alcohol 1:1.4. Complexed iron ion solution as activating agent was prepared by a consisting of 30 wt% trisodiun citrate, 10 wt% ethanediol, 30 wt% ferric sulfate (Fe2(SO4)3) and 30 wt% deionized water. The effects of gelling agent, activating agent and based fluid on oil-based fracturing fluid performance were examined. The experiments showed that with the increase of gelling agent dosage, the gelation time was significantly shortened and the viscosity gradually increased. When the amounts of gelling agent and activating agent were 2.5 wt% and 4 wt%, respectively, the gelling time and the viscosity of fracturing fluid was up to 166 s and 450 cP. The viscosities of the fracturing fluid were always greater than 100 cP after it was sheared by shear rate of 170 s−1 for 1 h at 80 °C, indicating that the fracturing fluid have good shearing resistance and temperature resistance. The viscosity of the fracture fluid with n-hexane as based fluid was 1.32 cP at 70 °C when the sodium acetate as broken gent was 0.40 wt%, thus the broken gelation effect was remarkable. And the core damage rate of prepared oil-based fracturing fluid was also much lower than that of the common water-based fracturing fluids.

Numerical Simulation of Immersed Liquid Cooling System for Lithium-Ion Battery Thermal Management System of New Energy Vehicles

Power batteries generate a large amount of heat during the charging and discharging processes, which seriously affects the operation safety and service life. An efficient cooling system is crucial for the batteries. This paper numerically simulated a power battery pack composed of 8 lithium-ion cells immersed in the coolant AmpCool AC-110 to study the effects of different coolants, different discharge rates, different coolant mass flow rates, different inlet temperatures and different inlet and outlet settings on the maximum temperature, the maximum temperature difference, the pressure drop, and the required pump power in the battery pack. Among the five coolants studied, W-E in water-based fluids has the best cooling effect, but because of high electric conductivity, it requires special considerations to avoid electric leakage. Increasing the mass flow rate of the coolant can significantly decrease Tmax and ΔTmax, but when the mass flow rate is already high, the decrease is limited and not obvious. Both Δp and the required pump power increase as the mass flow rate increases, and the required pump power increases faster. The inlet temperature will affect the physical properties of the coolant, and choosing the appropriate inlet temperature can not only decrease ΔTmax, but also decrease Δp and the required pump power in the battery pack. The range of 25~27 °C of the coolant AC-110 inlet temperature is recommended. For different inlet and outlet settings, the two-inlet two-outlet setting used in Case 7 has the best cooling effect, and the results indicate uniform distribution is very important to decrease temperature.

Presenting the best correlation relationship for predicting the dynamic viscosity of CuO nanoparticles in ethylene glycol -water base fluid using response surface methodology

The types of correlation relationships by different models for predicting of the dynamic viscosity of CuO nanoparticles (NPs) in the ethylene glycol (EG) (80 %)-Water (20 %) base fluid (BF) by using response surface methodology (RSM) statistical method under temperature conditions of T = 15 to 50 °C, solid volume fractions of SVF = 0.05 to 1 % and shear rate SR = 26.6 to 933.1 s−1 were investigated. Models of Quadratic, Cubic, 2FI and Quartic were investigated. These different models were analyzed based on the measurement criteria such as Correlation deviation, coefficient of determination, standard deviation, reliability and P-values; there are important parameters that were used to compare the models. Among these four models, the Quartic model has been chosen as superior model and used to optimize nanofluid (NF) viscosity. The optimization was done in cold environmental conditions and SVF, T, SR variables and viscosity were selected as minimum values and applied to the system. In the conditions of T = 25.303 °C, SVF = 0.05 % and SR = 26.660 sec-1, most optimal NF viscosity value was 8.565 mPa.sec.