Optimal Design of High-Speed Partial Flow Pumps using Orthogonal Tests and Numerical Simulations

To investigate the influence of structural parameters on the performances and internal flow characteristics of partial flow pumps at a low specific speed of 10000 rpm,special attention was paid to the first and second stage impeller guide vanes.Moreover,the impeller blade outlet width,impeller inlet diameter,blade inclination angle,and number of blades were considered for orthogonal tests.Accordingly,nine groups of design solutions were formed,and then used as a basis for the execution of numerical simulations(CFD)aimed at obtaining the efficiency values and heads for each design solution group.The influence of impeller geometric parameters on the efficiency and head was explored,and the“weight”of each factor was obtained via a range analysis.Optimal structural parameters were finally chosen on the basis of the numerical simulation results,and the performances of the optimized model were verified accordingly(yet by means of CFD).Evidence is provided that the increase in the efficiency and head of the optimized model was 12.11%and 23.5 m,respectively,compared with those of the original model.

Mechanical Test and Meso-Model Numerical Study of Composite Rubber Concrete under Salt-Freezing Cycle

A composite rubber concrete(CRC)was designed by combining waste tire rubber particles with particle sizes of 3~5 mm,1~3 mm and 20 mesh.Taking the rubber content of different particle sizes as the influencing factors,the range and variance analysis of the mechanical and impermeability properties of CRC was carried out by orthogonal test.Through analysis,it is concluded that the optimal proportion of 3~5 mm,1~3 mm,and 20 mesh particle size composite rubber is 1:2.5:5.5 kinds of CRC and 3 kinds of ordinary single-mixed rubber concrete(RC)with a total content of 10%~20%were designed under this ratio,and the salt-freezing cycle test was carried out with a concentration of 5%Na 2 SO4 solution.The physical and mechanical damage laws during 120 salt-freezing cycles are obtained,and the corresponding damage prediction model is established according to the experimental data.The results show that:on the one hand,the composite rubber in CRC produces a more uniform“graded”structure,forms a retractable particle group,and reduces the loss of mechanical properties of CRC.On the other hand,colloidal particles with different particle sizes are used as air entraining agent to improve the pore structure of concrete and introduce evenly dispersed bubbles,which fundamentally improves the durability of concrete.Under the experimental conditions,the CRC performance is the best when the overall content of composite rubber is 15%.

Optimization of Compound Coptis Ointment Extraction through the Integration of Pharmacodynamic Indices and Orthogonal Test

[Objectives]To determine the optimal reflux extraction process conditions for Compound Coptis Ointment.[Methods]The study employed the orthogonal experimental design method and drug-sensitive disc agar diffusion method to evaluate the extraction rate,berberine hydrochloride content,and bacteriostatic ring diameter of the extract as comprehensive indices,and optimized the extraction process conditions of Compound Coptis Ointment using ethanol reflux.[Results]Based on the results of comprehensive indices,the optimal reflux extraction conditions for Compound Coptis Ointment were determined to be soaking in 1.5 times the amount of 70%ethanol for 2 h,followed by two extractions with 6 times the amount of 70%ethanol for 1 h each time.Three verification tests were conducted under the optimal process conditions.The yield of the extract was 28.32%±0.53%,the content of berberine hydrochloride was 4.68%±0.45%,and the diameter of the bacteriostatic ring was(2.5±0.2)cm.[Conclusions]The extract had higher drug content and exhibited better antibacterial effects.The optimized extraction process is simple,stable,and reliable,and can be effectively used to optimize the extraction process of Compound Coptis Ointment.

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.

Optimization of short-circuit transition parameters of Q235B steel GMAW based on orthogonal gray relational analysis

In gas metal arc welding(GMAW)process,the short-circuit transition was the most typical transition observed in molten metal droplets.This paper used orthogonal tests to explore the coupling effect law of welding process parameters on the quality of weld forming under short-circuit transition,the design of 3 factors and 3 levels of a total of 9 groups of orthogonal tests,welding current,welding voltage,welding speed as input parameters:effective area ratio,humps,actual linear power density,aspect ratio,Vickers hardness as output paramet-ers(response targets).Using range analysis and trend charts,we can visually depict the relationship between input parameters and a single output parameter,ultimately determining the optimal process parameters that impact the single output index.Then combined with gray the-ory to transform the three response targets into a single gray relational grade(GRG)for analysis,the optimal combination of the weld mor-phology parameters as follows:welding current 100 A,welding voltage 25 V,welding speed 30 cm/min.Finally,validation experiments were conducted,and the results showed that the error between the gray relational grade and the predicted value was 2.74%.It was observed that the effective area ratio of the response target significantly improved,validating the reliability of the orthogonal gray relational method.

Heat dissipation enhancement method for finned heat sink for AGV motor driver's IGBT module

With the widespread use of high-power and highly integrated insulated gate bipolar transistor(IGBT),their cooling methods have become challenging.This paper proposes a liquid cooling scheme for heavy-duty automated guided vehicle(AGV)motor driver in port environment,and improves heat dissipation by analyzing and optimizing the core component of finned heat sink.Firstly,the temperature distribution of the initial scheme is studied by using Fluent software,and the heat transfer characteristics of the finned heat sink are obtained through numerical analysis.Secondly,an orthogonal test is designed and combined with the response surface methodology to optimize the structural parameters of the finned heat sink,resulting in a 14.57%increase in the heat dissipation effect.Finally,the effectiveness of heat dissipation enhancement is verified.This work provides valuable insights into improving the heat dissipation of IGBT modules and heat sinks,and provides guidance for their future applications.

Orthogonal tests of copper-clad aluminum bimetal continuous casting by nitrogen pressure core-illing

To provide theoretical basis and practical guidance for preparing composite rods by direct continuous casting, copper-clad aluminum composite rods of external copper layer diameter 12 mm and inner aluminum core diameter 8 mm were manufactured. Orthogonal tests consisted of three factors and three levels were carried out to research the effects of melting copper temperature, continuous casting speed and nitrogen pressure on the performance of composite rods. Results showed that nitrogen pressure is the most important factor in influencing the surface quality; continuous casting speed is the most important factor in influencing copper & aluminum inter diffusion amount. Nitrogen pressure can noticeably improve the surface quality and make the rods easily be drawn out, but the surface quality does not show visible improvement when the nitrogen pressure is above 0.05 MPa. Measured by tests, the compound layer can be divided into three types according to its cladding layer degree: deficient cladding, normal cladding and excess cladding. The diameter of normal copper-clad aluminum composite rods can be successfully drawn less than 0.6 mm without annealing.

Mathematical model for abrasive suspension jet cutting based on orthogonal test design

This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.

Orthogonal tests of lead-clad tin bimetal continuous casting by air pressure core-filling

To provide theoretical basis and practical guidance for preparing composite rods of external diameter no larger than 12 mm by directly continuous casting,low melting point materials of lead and tin were selected to prepare composite rods of external diameter 12 mm and inner diameter 8 mm with air pressing core filled continuous casting process.The orthogonal tests consisting of three factors and three levels were designed to investigate the parameters of melting lead temperature,continuous casting speed and air pressure that affect the performance of the composite rods.The results show that melting lead temperature is the most important factor that influences the solid/liquid interface location;continuous casting speed is the most important factor that influences the surface quality and lead and tin inter-diffusion amount;air pressure can improve the surface quality obviously and make the rods easily drawn out,but the surface quality cannot get obvious improvement when the air pressure is above 0.03 MPa.The composite rods have excellent surface quality,obvious intermediate layer,even thick clad,and metallurgical bonding interface under the condition of melting lead temperature of 375 °C,continuous casting speed of 10 mm/min,and air pressure of 0.03 MPa.

Orthogonal Test About Biogas Upgrading by Pressured Water Scrubbing

Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.

Optimization of Extraction Process of Zihua Qinghuo Capsule by Orthogonal Test

With quercetin content and yield of dry extract as investigation indices, three factors, amount of water added, decoction time and decoction times were investigated by an orthogonal test, so as to select the optimal water extraction process for Zihua Qinghuo Capsule. The determined extraction process was adding 8 times of water in five herbs including Viola philippica and decocting for 2 times, 1.5 h each time. Pilot scale test demonstrated that the selected process is stable and feasible, and could provide reliable reference for practical production.

Study on the insecticidal activities of the extracts from four plants under orthogonal test

Aim To prepare dry powder insecticide by mixing the plant samples of Aconitum ochranthum Mey.,Aconitum hemsleyanum Pritz.and Dictamnus dasycarpus Turcz.Method The dosage ratios of the break stocks from the plants mentioned above are installed as four factors,and three levels are selected for every factor.The test is actualized according to L 9(3 4) orthogonal array.Results An optimized recipe A 3 B 3 C 3 D 1 has been obtained after considering multifarious factors such as the resources of these plants and the water-solubility of samples.Conclusion The dry powder insecticide prepared by mixing the plant samples mentioned above as 1∶1∶1mass ratio revealed that insecticidal activities for cickets,grasshopper,aphid,and 3rd instar Mythimna separata walker are significant,respectively.

Warm Compaction Process of P/M Steels by Orthogonal Testing Method

In order to achieve higher density of P/M steels using the die wall lubrication compacting method or powder lubricant in warm compaction process, the influence of different process parameters on the green density of warm compacted samples was studied. According to the orthogonal test method, the authors systematically study the influence of the different compaction pressure, condition of lubrication and compaction temperature on the green density of the sample in the warm compaction process, and put forward the optimal process parameter of warm compaction experiment. It is found that, a high compaction pressure （≥700 MPa）, die wall lubrication combined with a small amount of internal lubricants, and fitting compaction temperature by different condition of lubrication, are the optimal parameters in warm compaction process.

Fuzzy Analysis Method for Orthogonal Test on Seed Propagation of Eurya chinensis

Fuzzy analysis method for orthogonal test was used to study the effect of different sowing depth, seed soaking time, illumination intensity and culture soil on the seed germination rate of Eurya chinensis. The results showed that the effect of seed soaking time on the sowing and seedling of Eurya chinensis was the biggest, and the ethers were illumination intensity, sowing depth and culture soil. The germi- nation rate was the highest when composite soil was used as culture soil and seeds were soaked for 48 h and sowed in topsoil, and a layer of sunshade net was used.

Optimization of the Ethanol Extraction Method of Monoester Alkaloids from Radix Aconiti Preparata Based on HPLC-MS and Orthogonal Test

[Objectives] This study was conducted to optimize the ethanol extraction technology of monoester alkaloids from Radix Aconiti Preparata. [Methods]On the basis of defined extraction times,ethanol concentration,ethanol times and extraction time were investigated by HPLC-MS combined with orthogonal test to optimize extraction process using the content of monoester alkaloids( the sum of benzoyl neoaconitine,benzoyl hypoaconitine and benzoyl aconitine) as an index.[Results]The optimum ethanol extraction technology was as follows: 75% ethanol,ethanol amount 25 times of the medicinal material,and each extraction for 1. 5 h.[Conclusions] The optimal extraction technology is simple,feasible,stable and reliable. It can provide reference for the industrial production and quality control of monoester alkaloids from Radix Aconiti Preparata.

Research on Treatment of Landfill Leachate Polluting Groundwater by Orthogonal Test

Through PRB simulated device and orthogonal test,we discussed the treatment effect of groundwater polluted by landfill leachate with three reaction mediums of zero-valent iron powder,activated carbon and zeolite. We considered four factors of iron powder mass,activated carbon mass,particle size of iron powder and zeolite mass,and designed a two-level orthogonal test. It concluded that effluent pH appeared to fall or rise as the reaction proceeded,which changed during 7- 8. The removal rates of CODCrin eight reactors were during 60. 7%- 78. 3%,and the removal rates of NH3-N were during 34. 0%- 58. 8%. Activated carbon mass and the interaction of iron powder mass and activated carbon mass had significant influences on the removal of CODCr,while iron powder mass,particle size of iron powder and zeolite mass had insignificant influences on the removal of CODCr. Zeolite mass and activated carbon mass had significant influences on the removal of NH3,while iron powder mass,particle size of iron powder and the interaction with activated carbon mass had insignificant influences on the removal of NH3-N.

Characteristics of snow cover distribution along railway subgrade and the protective effect of snow fences

Railways built in cold,snowy,and lightly populated areas are subjected to wind and snow disasters.In this study,we selected a snow hazard prevention and control section of the Altay–Zhundong Railway in Xinjiang Uygur Autonomous Region of China as the research object.We investigated the deposited snowfall variation characteristics on the two sides and in the embankment pavement area of snow fences with different porosities,fence heights,and arrangement distances using single-factor tests and orthogonal tests based on global atmospheric reanalysis climate data,field survey data,and a multi-phase flow analysis model.The results showed significant differences in the characteristics of snow cover distribution and snow cover thickness between the embankment and the cutting in the absence of snow protection measures.The maximum snow cover thickness of the embankment pavement decreased by 12.6%relative to the cutting pavement.The snow cover thickness of the embankment exhibited an increasing trend from windward shoulder to leeward shoulder,whereas the snow cover thickness of the cutting presented a declining trend from windward shoulder to leeward toe.In the collaborative prevention and control of snow fences and embankments,the three factors can be ranked in terms of their sensitivity to deposited snowfall within the influence scope of snow fences as follows:fence height>arrangement distance>porosity.At the same time,fence height yielded a significant relationship for the influence scope of snow fences(P<0.05).The three factors can also be ranked in terms of their sensitivity to deposited snowfall on the pavement as follows:porosity>fence height>arrangement distance.For the embankment protection of the Altay–Zhundong Railway against wind and snow,snow fence with a porosity of 75%,a fence height of 4.8 m,and an arrangement distance from the embankment of 60 m produced the best snow control effect.By revealing the characteristics of snow cover distribution along railway subgrade and the protective effect of snow fences,this study provides valuable references for the engineering applications of railway construction in areas prone to wind and snow disasters.

Continuous Process Optimization and Computational Fluid Dynamics Simulation of a Methyl Anthranilate Jet Reactor

Methyl anthranilate(MA)is an important material for the synthesis of sodium saccharin,but the yield and quality of MA are not stable due to the batch operation conditions.In this study,the optimum conditions obtained by an orthogonal test in a batch reactor were a volume ratio of methanol to amide solution of 5:4,volume ratio of sodium hypochlorite to amide solution of 7:4,Hoffmann degradation reaction duration of 10 min,Hoffmann degradation reaction temperature of 10℃,esterification reaction duration of 10 min,and esterification reaction temperature of 40℃.The working flow velocity and allowable working viscosity range of a Venturi ejector inlet were both determined by a computational fluid dynamics(CFD)simulation.Based on the above experimental data,the continuous operation of the process was tested in a three-stage continuous reactor,which improved the product yield and quality of the process.

Experimental study on the failure factors of the O-ring for long-term working

The O-ring in the rotary dynamic sealing system of gas meters should have outstanding long-term sealing performance under the conditions of high and low temperature,which can ensure the safety of gas meters.In this paper,based on the O-ring sealing mechanism,taking the compression set as the main sealing index,a finite element simulation method is used to analyze the failure charac-teristics under different conditions according to the constitutive relation of nitrile rubber.Then,using the orthogonal test method for the O-ring sealing performance index,the main factors which affect the law of long-term test are analysed,and the orthogonal regression mathematical model that can predict the compression set is obtained.Finally,the O-ring is improved according to the model,and the test results show that the performance of the new O-rings with high and low temperature resistance is greatly improved and meets the expected target requirements.

Optimization of the Formulation Process of Glucosamine Chondroitin Sulfate Tablets

[Objectives]This study was conducted to optimize the Formulation Process of glucosamine chondroitin sulfate tablets. [Methods] The orthogonal design with three levels was carried out with microcrystalline cellulose, calcium hydrophosphate and cross-linked polyvinylpyrrolidone as three factors to optimize the preparation process. [Results] When microcrystalline cellulose 200 mg/tablet, calcium hydrophosphate 150 mg/tablet, and cross-linked polyvinylpyrrolidone 80 mg/tablet were added, the angle of repose could meet the requirements of tablet pressing, and the dissolution could reach more than 95% in 30 min. The results of the orthogonal test showed that the dissolution effect of self-made tablets was faster than that of commercial products. [Conclusions] The glucosamine hydrochloride chondroitin sulfate tablets prepared by this prescription have better quality.