Water-Air Mixing Jet Produced by Electro-hydraulic Impulse Technology Strengthening the Quality of Surface of Metal Materials

Electro-hydraulic impulse water-air mixing jet by which the quality of metal materials can be improved is described in this paper. The experimental results proved that the hardness and the micro-hardness of the surface layer of metal materials can be improved with this method, for example, the microhardness of CrWMn can be increased by 35.62 percent.

Optimization of a Lobed Mixer with BP Neural Network and Genetic Algorithm

A Sequential Approximate Optimization framework(SAO)for the multi-objective optimization of lobed mixer is established by using the BP neural network and Genetic Algorithm:the ratio of lobe wavelength to height(η)and the rise angle(α)are selected as the design parameters,and the mixing efficiency,thrust and total pressure loss are the optimization objectives.The CFX commercial solver coupled with the SST turbulence model is employed to simulate the flow field of lobed mixer.A tetrahedral unstructured grid with 5.6 million cells can achieve the similar global results.Based on the response surface approximation model of the lobed mixer,it is necessary to avoid increasing or decreasingαandηat the same time.Instead,theαshould be reduced while theηis appropriately increased,which is conducive to achieving the goal of increasing thrust and reducing losses at the expense of a small decrease in the mixing efficiency.Compared with the normalized method,the non-normalized method with better global optimization accuracy is more suitable for solving the multi-objective optimization problem of the lobed mixer,and its optimal solution(α=8.54°,η=1.165)is the optimal solution of the lobed mixer optimization problem studied in this paper.Compared with the reference lobed mixer,theα,β(the fall angle)and H(lobe height)of the optimal solution are reduced by 0.14°,1.34°and 3.97 mm,respectively,and theηis increased by 0.074;its mixing efficiency is decreased by 4.46%,but the thrust is increased by 2.29%and the total pressure loss is decreased by 0.64%.Downstream of the optimized lobed mixer,the radial scale and peak vorticity of the streamwise voritices decrease with the decreasing lobe height,thereby reducing the mixing efficiency.For the optimized lobed mixer,its low mixing efficiency is the main factor for the decrease of the total pressure loss,but the improvement of the geometric curvature is also conducive to reducing its profile loss.Within the scope of this study,the lobed mixer has an optimal mixing efficiency(ε=74.14%)that maximizes its thrust without excessively increasing the mixing loss.

Facile pathway to generate agrochemical nanosuspensions integrating super-high load, eco-friendly excipients, intensified preparation process, and enhanced potency

An aqueous nanosuspension of agrochemicals unlike pharmaceutics has to achieve massive production in an effective way,capable to ensure sufficient profits in commercialization.This work implements the flash nanoprecipitation(FNP)technique to effectively generate agrochemical nanosuspension,anticipatedly overcoming such an obstacle.Azoxystrobin,a broad spectrum fungicide,in either acetone or ethanol is used herein as a mode agrochemical.To ensure a green and practical utilization,three kinds of commercially available and eco-friendly surfactants,i.e.,poly(ethylene glycol)-block-poly(lactic-co-glycolic acid)(PEG-b-PLGA),Tween 80 and alkyl polyglucosides(APGs),are employed for stabilizing the nanoparticles.The results show that the polymeric stabilizer,PEG-b-PLGA,has the best stabilization efficiency,and can maintain the particles below 100 nm for at least three weeks.The azoxystrobin load of the nanoparticles reaches as high as 77 wt.%,beneficial to enhancing the biological potency.Moreover,the FNP brings the particles a much smaller size,narrower size distribution,better size stability,and higher biological efficacy than the ones made via a traditional method of the drop and stir(DS).The nanosuspensions present superior fungicidal performances over a prevailing counterpart from Syngenta.This study proves an enhanced biological potency and reduced dosage of agrochemical nanosuspension made via the FNP,indicating a remarkable advantage of the FNP over the conventional preparation.The integration of a super-high load,eco-friendly excipients,intensified preparation process,enhanced potency,and reduced dosage creates a promising pathway to generate a green aqueous nanosuspension of agrochemicals.

Effect of methane-hydrogen mixtures on flow and combustion of coherent jets

Coherent jets are widely used in electric are furnace （EAF） steelmaking to increase the oxygen utilization and chemical reaction rates. However, the influence of fuel gas combustion on jet behavior is not fully understood yet. The flow and combustion characteristics of a coherent jet were thus investigated at steelmaking temperature using Fluent software, and a detailed chemical kinetic reaction mecha- nism was used in the combustion reaction model. The axial velocity and total temperature of the supersonic jet were measured via hot state experiments. The simulation results were compared with the experimental data and the empirical jet model proposed by Ito and Muchi and good consistency was obtained. The research results indicated that the potential core length of the coherent jet can be prolonged by optimizing the combustion effect of the fuel gas. Besides, the behavior of the supersonic jet in the subsonic section was also investigated, as it is an important factor for controlling the position of the oxygen lance. The investigation indicated that the attenuation of the coherent jet is more notable than that of the conventional jet in the subsonic section.