Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Cobalt(Co)serves as a stabilizer in the lattice structure of high-capacity nickel(Ni)-rich cathode materials.However,its high cost and toxicity still limit its development.In general,it is possible to perform transition metal substitution to reduce the Co content.However,the traditional coprecipitation method cannot satisfy the requirements of multielement coprecipitation and uniform distribution of elements due to the differences between element concentration and deposition rate.In this work,spray pyrolysis was used to prepare LiNi_(0.9)Co_(0.1-x)W_(x)O_(2)(LNCW).In this regard,the pyrolysis behavior of ammonium metatungstate was analyzed,together with the substitu-tion of W for Co.With the possibility of spray pyrolysis,the Ni-Co-W-containing oxide precursor presents a homogeneous distribution of metal elements,which is beneficial for the uniform substitution of W in the final materials.It was observed that with W substitution,the size of primary particles decreased from 338.06 to 71.76 nm,and cation disordering was as low as 3.34%.As a consequence,the pre-pared LNCW exhibited significantly improved electrochemical performance.Under optimal conditions,the lithium-ion battery assembled with LiNi_(0.9)Co_(0.0925)W_(0.0075)O_(2)(LNCW-0.75mol%)had an improved capacity retention of 82.7%after 200 cycles,which provides insight in-to the development of Ni-rich low-Co materials.This work presents that W can compensate for the loss caused by Co deficiency to a cer-tain extent.

HVOF-sprayed HAp/S53P4 BG composite coatings on an AZ31 alloy for potential applications in temporary implants

Bioactive thermal spray coatings produced via high-velocity oxygen fuel spray(HVOF)from hydroxyapatite(HAp)and bioactive glasses(BG)have the potential to be employed on temporary implants due to the ability of both HAp and BG to dissolve and promote osseointegration,considering that both phases have different reaction and dissolution rates under in-vitro conditions.In the present work,75%wt.HAp-25%wt.S53P4 bioactive glass powders were HVOF-sprayed to obtain HAp/S53P4 BG composite coatings on a bioresorbable AZ31 alloy.The study is focused on exploring the effect of the stand-off distance and fuel/oxygen ratio variation as HVOF parameters to obtain stable structural coatings and to establish their effect on the phases and microstructure produced in those coatings.Different characterization techniques,such as scanning electron microscopy,X-ray diffraction,and Fourier transform infrared spectroscopy,were employed to characterize relevant structural and microstructural properties of the composite coatings.The results showed that thermal gradients during coating deposition must be managed to avoid delamination due to the high temperature achieved(max 550℃)and the differences in coefficients of thermal expansion.It was also found that both spraying distance and oxygen/fuel ratio allowed to keep the hydroxyapatite as the main phase in the coatings.In addition,in-vitro electrochemical studies were performed on the obtained HAp/S53P4 BG composite coatings and compared against the uncoated AZ31 alloy.The results showed a significant decrease in hydrogen evolution(at least 98%)when the bioactive coating was applied on the Mg alloy during evaluation in simulated body fluid(SBF).

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater configurations.For the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting methods.During the cutting process,aerosol particles are expected to be generated at the submicron scale.It has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying methods.Therefore,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water sprays.In this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water mist.The experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water mist.The results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

Simulation Study on the Heat Transfer Characteristics of a Spray-Cooled Single-Pipe Cooling Tower

The current study focuses on spray cooling applied to the heat exchange components of a cooling tower.An optimization of such processes is attempted by assessing different spray flow rates and droplet sizes.For simplicity,the heat exchanger of the cooling tower is modeled as a horizontal round tube and a cooling tower spray cooling model is developed accordingly using a computational fluid dynamics(CFD)software.The study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube and the surrounding air,taking into account the number of nozzles.It is observed that on increasing the spray flow strength,the heat flow intensity and extent of the liquid film in the system are enhanced accordingly.Moreover,the magnitude of droplet size significantly impacts heat transfer.A larger droplet size decreases evaporation in the air and enhances the deposition of droplets on the round tube.This facilitates the creation of the liquid film and enhances the passage of heat between the liquid film and air.Increasing the number of nozzles,while maintaining a constant spray flow rate,results in a decrease in the flow rate of each individual nozzle.This decrease is not favorable in terms of heat transfer.

Investigation of the Film Formation in Dynamic Air Spray Painting

To accurately predict the film thickness distribution during dynamic spraying performed with air guns and support accordingly the development of intelligent spray painting,the spray problem was analyzed numerically.In particular,the Eulerian-Eulerian approach was employed to calculate the paint atomization and film deposition process.Different spray heights,spray angles,spray gun movement speeds,spray trajectory curvature radii,and air pressure values were considered.Numerical simulation results indicate that the angle of spray painting significantly affects the velocity of droplets near the spray surface.With an increase in the spraying angle,spraying height and spray gun movement speed,the maximum film thickness decreases to varying degrees,and the uniformity of the film thickness also continuously worsens.When the spray gun moves along an arc trajectory,at smaller arc radii,the film thickness on the inside of the arc is slightly greater than that on the outside,but the impact on the maximum film thickness is minimal.Increasing air pressure expands the coating coverage area,results in finer atomization of paint droplets,and leads to a thinner and a more uniform paint film.However,if the pressure is too high,it can cause paint splattering.Using the orthogonal experimental method,multiple sets of simulation calculations were conducted,and the combined effects of spraying height,spray angle,and spray gun movement speed on the film thickness distribution were comprehensively analyzed to determine optimal configurations.Finally,the reliability of the numerical simulations was validated through dynamic spray painting experiments.

Effects of plasma spraying process on microstructure and mechanical properties of Cr_(2)AlC/410 composite coatings

To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatings containing different mass fractions of Cr_(2)AlC were prepared and investigated.The composite coating exhibited low porosity and high adhesion strength.The addition of Cr_(2)AlC significantly enhanced the hardness of the composite coatings through particle strengthening.However,when the mass fraction of Cr_(2)AlC was 20%,the aggregation of Cr_(2)AlC resulted in a strong decrease in the coating preparation efficiency,as well as a decline in adhesion strength.In the supersonic plasma spraying process,the Ar flow rate mainly influenced the flight velocity of the particles,while the H_(2) flow rate and the current mainly affected the temperature of the plasma torch.Consequently,all of them influenced the melting degree of particles and the quality of the coating.The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min,the H_(2) flow rate is 25 L/min,and the current is 385 A.

Effect of cold rolling deformation on microstructure evolution and mechanical properties of spray formed Al−Zn−Mg−Cu−Cr alloys

The impact of cold rolling deformation,which was introduced after solid solution and before aging treatment,on microstructure evolution and mechanical properties of the as-extruded spray formed Al−9.8Zn−2.3Mg−1.73Cu−0.13Cr(wt.%)alloy,was investigated.SEM,TEM,and EBSD were used to analyze the microstructures,and tensile tests were conducted to assess mechanical properties.The results indicate that the D1-T6 sample,subjected to 25%cold rolling deformation,exhibits finer grains(3.35μm)compared to the D0-T6 sample(grain size of 4.23μm)without cold rolling.Cold rolling refines the grains that grow in solution treatment.Due to the combined effects of finer and more dispersed precipitates,higher dislocation density and smaller grains,the yield strength and ultimate tensile strength of the D1-T6 sample can reach 663 and 737 MPa,respectively.In comparison to the as-extruded and D0-T6 samples,the yield strength of the D1-T6 sample increases by 415 and 92 MPa,respectively.

Preparation and Properties of Spray Polyurea Elastomer for Aquaculture Foam Floating Balls

[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

Designing an Experimental Device for Swinging Excitation Spray Cooling

In this paper,we introduce the design principle of the oscillating excited spray cooling experimental device.We then designed an oscillating excited spray cooling experimental device.By using the device,the swaying motion can be realized through the control system,and the motion of the droplet under different vibration frequencies can be observed.By measuring the liquid flow rate and pressure,the changes in liquid flow rate,pressure,and temperature with time under different vibration frequencies were studied.The trajectory of the droplet and the temperature distribution of the droplet under different vibration frequencies could be observed.The device has a simple structure,is easy to control,and can achieve continuous observation of the spray cooling process.

Time-optimal rendezvous transfer trajectory for restricted cone-angle range solar sails

The advantage of solar sails in deep space exploration is that no fuel consumption is required. The heliocentric distance is one factor influencing the solar radiation pressure force exerted on solar sails. In addition, the solar radiation pressure force is also related to the solar sail orientation with respect to the sunlight direction. For an ideal flat solar sail, the cone angle between the sail normal and the sunlight direction determines the magnitude and direction of solar radiation pressure force. In general, the cone angle can change from 0° to 90°. However, in practical applications, a large cone angle may reduce the efficiency of solar radiation pressure force and there is a strict requirement on the attitude control. Usually, the cone angle range is restricted less more than an acute angle （for example, not more than 40°） in engineering practice. In this paper, the time-optimal transfer trajectory is designed over a restricted range of the cone angle, and an indirect method is used to solve the two point boundary value problem associated to the optimal control problem. Relevant numerical examples are provided to compare with the case of an unrestricted case, and the effects of different maximum restricted cone angles are discussed. The results indicate that （1） for the condition of a restricted cone-angle range the transfer time is longer than that for the unrestricted case and （2） the optimal transfer time increases as the maximum restricted cone angle decreases.

Influence of Spray Gun Position and Orientation on Liquid Film Development along a Cylindrical Surface

A method combining computationalfluid dynamics(CFD)and an analytical approach is proposed to develop a prediction model for the variable thickness of the spray-induced liquidfilm along the surface of a cylindrical workpiece.The numerical method relies on an Eulerian-Eulerian technique.Different cylinder diameters and positions and inclinations of the spray gun are considered and useful correlations for the thickness of the liquidfilm and its distribution are determined using various datafitting algorithms.Finally,the reliability of the pro-posed method is verified by means of experimental tests where the robot posture is changed.The provided cor-relation are intended to support the optimization of spray-based coating applications.

Sea spray induced air-sea heat and salt fluxes based on the wavesteepnessdependent sea spray model

Sea spray,which comprises amounts of small ocean droplets,plays a significant role in the air-sea coupling,atmospheric and oceanic dynamics,and climate.However,it remains arduous to arrive at estimates for the efficiency and accuracy of the sea spray induced air-sea heat and salt fluxes.This is because the microphysical process of sea spray evolution in the air is of extreme complexity.In this study,we iteratively calculated the sea spray induced air-sea heat and salt fluxes at various weather condition.To do so,we implemented one novel wave-steepness-dependent sea spray model into a bulk air-sea fluxes algorithm and utilized other sea spray models as comparisons.Based on the improved wave-dependent bulk turbulent algorithm,we observed that despite the negative contribution of sea spray to the sensible heat fluxes,the sea spray positively contributes to the air-sea latent heat fluxes,leading to an overall increase in the total air-sea heat fluxes.The additional heat fluxes caused by sea spray may be the missing critical process that can clarify the discrepancies observed between measured and modelled Tropical Cyclone’s development and intensification.In addition to heat fluxes,we observed that sea spray has significant impacts on the air-sea salt fluxes.As the sea salt particles are one of the main sources of the atmosphere aerosol,our results imply that sea spray could impact global and regional climate.Thus,given the significance of sea spray on the air-sea boundary layer,sea spray effects need to be considered in studies of air-sea interaction,dynamics of atmosphere and ocean.

The Influence of Sea Sprays on Drag Coefficient at High Wind Speed

Field and laboratory observations indicate that the variation of drag coefficient with wind speed at high winds is different from that under low-to-moderate winds.By taking the effects of wave development and sea spray into account,a new parameterization of drag coefficient applicable from low to extreme winds is proposed.It is shown that,under low-to-moderate wind conditions so that the sea spray effects could be neglected,the nondimensional aerodynamic roughness first increases and then decreases with the increasing wave age;whereas under high wind conditions,the drag coefficient decreases with the increasing wind speed due to the modification of the logarithmic wind profile by the effect of sea spray droplets produced by bursting bubbles or wind tearing breaking wave crests.The drag coefficients and sea surface aerodynamic roughnesses reach their maximum values vary under different wave developments.Correspondingly,the reduction of drag coefficient under high winds reduces the increasing rate of friction velocity with increasing wind speed.

Experimental study on the improvement of spray characteristics of aero-engines using gliding arc plasma

A gliding arc plasma fuel atomization actuator suitable for aeroengines was designed,and a gliding arc plasma fuel spray experimental platform was built to address the fuel atomization problem in aeroengine combustion chambers.The spray characteristics for different airflows,fuel flows,and discharge voltages were analyzed using laser particle size analysis.The research shows that the fuel atomization effect is improved from the increased airflow.The decreased fuel flow not only reduces the injection pressure of the fuel but also changes the discharge mode of the gliding arc,which affects reductions in the discharge power and inhibits fuel atomization.Gliding arc discharges accelerate the breaking,atomization,and evaporation of fuel droplets while reducing the particle size,which increases the proportion of small droplets.Compared with the working conditions of plasma-assisted atomization without the gliding arc,the D0.5,D0.9,and average particle size of the fuel droplets are reduced by 4.7%,6.5%,and 4.1%,respectively,when the modulation voltage of the gliding arc power supply is 200 V.

Effect of Intake Conditions and Nozzle Geometry on Spray Characteristics of Group-Hole Nozzle

The group-hole nozzle concept is proposed to meet the requirement of nozzle hole minimization and reduce the negative impact of poor spatial spray distributions.However,there are limited researches on the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle.Therefore,in this study,an accurate spray model coupled with the internal cavitating flow was established and computational fluid dynamics(CFD)simulations were done to study the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle.Experimental data obtained using high-speed digital camera on the high-pressure common rail injection system was used to validate the numerical model.Effects of intake conditions(injection pressure and temperature)and nozzle geometry(orifice entrance curvature radius and nozzle length)on the flow and spray characteristics of the group-hole nozzle were studied numerically.The differences in Sauter mean diameter(SMD),penetration length and fuel evaporation mass between single-hole nozzle and group-hole nozzle under different nozzle geometry were also discussed.It was found that the atomization performance of the group-hole nozzle was better than that of the single-hole nozzle under same intake conditions,and the atomization effect of the short nozzle was better than that of the long nozzle.With increase in the orifice entrance curvature radius,the average velocity and turbulent kinetic energy of the fuel increased,which was conducive to improving the injection rate and flow coefficient of the nozzle.Meanwhile,the penetration length and SMD value rose,while evaporation mass dropped.When the ratio of the orifice entrance curvature radius(R)to the diameter of injection hole(D)was 0.12,the spray characteristics reached a constant state due to elimination of cavitation.Conclusions were made based on these.This study is expected to be a guide for the design of the group-hole nozzle.

Experimental Investigation on Macro Spray Characteristics of Octanol-Biodiesel-Diesel Ternary Fuel Blend

This study investigates the spray characteristics of ternary blends composed of octanol, biodiesel, and diesel fuel.Experiments are conducted using six materials to examine the variation in spray characteristic and to verify and compare a previously established spray tip penetration model with a modified model. The results show that the addition of OB100(30%of octanol, 70% of biodiesel) improves the spray characteristics of the fuel. Specifically, the addition of 10% or 20% of OB100 leads to a slight increase in the spray tip penetration, average spray cone angle, maximum spray width, and the spray area of the fuel blend;however, further addition of OB100 causes a corresponding decrease in these parameters. Based on previous research, this study uses kinematic viscosity instead of dynamic viscosity and density to modify the prediction model of spray tip penetration. The modified model exhibits a better fit quality and agreement with the experimental data,making it more suitable for predicting the spray tip penetration of fuel blends compared to the Hiroyasu-Arai model.

Residual stress with asymmetric spray quenching for thick aluminum alloy plates

Solution and quenching heat treatments are generally carried out in a roller hearth furnace for large-scale thick aluminum alloy plates.However,the asymmetric or uneven spray water flow rate is inevitable under industrial production conditions,which leads to an asymmetric residual stress distribution.The spray quenching treatment was conducted on self-designed spray equipment,and the residual stress along the thickness direction was measured by a layer removal method based on deflections.Under the asymmetric spray quenching condition,the subsurface stress of the high-flow rate surface was lower than that of the low-flow rate surface,and the difference between the two subsurface stresses increased with the increase in the difference in water flow rates.The subsurface stress underneath the surface with a water flow rate of 0.60 m^(3)/h was 15.38 MPa less than that of 0.15 m^(3)/h.The simulated residual stress by finite element(FE)method of the high heat transfer coefficient(HTC)surface was less than that of the low HTC surface,which is consistent with the experimental results.The FE model can be used to analyze the strain and stress evolution and predict the quenched stress magnitude and distribution.

Enhancing energetic performance of metal-organic complex-based metastable energetic nanocomposites by spray crystallization

Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity and functionality of the novel energetic nanocomposites are still limited.In this work,spray crystallization(SC)method was used to prepare novel energetic nanocomposites,the high-energy metal-organic complex[Ni(CHZ)_(3)](ClO_(4))_(2)(CHZ=1,3-diaminourea)was composited with nanoaluminum(n-Al).Results showed that n-Al/[Ni(CH_(2))_(3)](ClO_(4))_(2)energetic nanocomposites prepared by SC method increased heat release to 2977.6 J/g and peak pressure to 3.91 MPa with higher pressurization rate(1324.06 MPa/s),decreased sensitivity thresholds(>100 mJ)to electrostatic discharge(ESD)and enhanced detonation ability compared with[Ni(CHZ)_(3)](ClO_(4))_(2)alone and physically mixed(PM)n-Al/[Ni(CHZ)_(3)](ClO_(4))_(2).These results proved that it is significant to introduce energetic metal-organic complexes with inherent high energy in new-concept n-Al/energetic metal-organic complexes nanocomposites through SC method for a better performance of its application.

Spray Characteristics of Non-Circular Nozzle in Air-Assisted Injection System

In order to analyze the spray characteristics of non-circular nozzle holes based on the air-assisted spray system, the spray characteristics of circular and non-circular nozzles were studied under the pressure of 0.2-0.6 MPa and the spray volume of 1000-5000 mL/h. Elliptical nozzle and triangular nozzle are classified as non-circular geometries. The spray cone angle was measured by processing the spray image captured by a CCD camera. The measured spray cone angles of the circular nozzles were analyzed, and the axis switching phenomenon of minor plane of elliptical nozzle was found during the test. Among the three shapes of nozzles, the elliptical nozzle had the largest spray cone angle, and the triangular nozzle had the smallest. The velocity field obtained depended on the PIV system. The results show that for axial velocity, elliptical orifice spray has greater kinetic energy and smaller droplet size under the same working parameters. Compared with the circular and elliptical nozzles, triangular orifice reached maximum spray velocity the fastest, but its velocity decay was the fastest. For radial velocity, away from the axis, the spray velocity of the elliptical orifice was less affected by the injection parameters, and the velocity was less than that of circular orifice and triangle orifice. Increasing air pressure will weaken radial propagation. The increase of liquid spraying rate had no remarkable effect on the increase of spraying rate. The results of particle size analysis show that the particle size of the non-circular orifice is reduced compared with that of the circular orifice, which promotes the breakup of droplets to a certain extent and enhances the atomization effect.