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.

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.

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.

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.

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.

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.

Preparation Process and Quality Standard of Rougan Huaxian Ointment

[Objectives] To establish the preparation process and quality standard of Rougan Huaxian ointment.[Methods] The L 9(3 4) orthogonal test was employed to optimize the preparation process by considering the multiplication of water addition, extraction time, and extraction frequency as influencing factors. The dry paste yield was utilized as the evaluation criterion, in conjunction with the actual production conditions. Thin layer chromatography was employed to identify Radix Astragali, Lycii Fructus, Herba Dendrobii, and Rhizoma Polygoni Cuspidati. Ethanol served as the solvent for the determination of ethanol-soluble extractives using the cold immersion method.[Results] The preparation process was conducted as follows: the specified quantity of medicinal materials was combined with water for extraction purposes, performed in two separate stages. In each stage, eight times the amount of water was added. The first extraction lasted for 1.5 h, while the second extraction was completed in 1.0 h. The resulting liquid was then concentrated into a thick paste with a relative density ranging from 1.25 to 1.30 at a temperature of 60 ℃. The thin-layer chromatography analysis of Radix Astragali, Lycii Fructus, Herba Dendrobii, and Rhizoma Polygoni Cuspidati demonstrated distinct spots, effective separation, and the absence of interference from negative samples. Additionally, the ethanol-soluble extractives yielded a minimum of 8.0% in terms of dry weight.[Conclusions] The preparation process for Rougan Huaxian ointment is both stable and feasible. Furthermore, the quality standards established for this preparation are unique and reproducible, thereby facilitating effective quality control.

Extraction and Content Determination of Shikimic Acid in Pinus elliottii Engelm

[Objective] The aim was to provide scientific basis for development and utilization of Pinus elliottii Engelm resources.[Method] The extraction process of shikimic acid in Pinus elliottii Engelm was studied,and the content of shikimic acid was determined by HPLC.The HPLC conditions were as follows;Alltima NH2 （5 μm,4.6 mm × 150 mm） column separation;the mobile phase was acetonitrile-2%H3PO4 （90：10）;the flowing velocity was 1 ml/min;test wavelength was 213 nm,the width of belt was 16 nm;reference wavelength was 300 nm,the width of belt was 80 nm.[Result] By the single factor and orthogonal tests,the optimum conditions were found as follows：ethanol concentration 60%,extraction temperature 75 ℃,solid-liquid ratio 1：25,extraction time 2.5 h.The extraction rate of shikimic acid was 1.49%.[Conclusion] Shikimic acid in Pinus elliottii Engelm could be used as a new resource to develop and utilize.

Study on Fermentation Conditions of Pycnoporus sanguineus

[Objective] The purpose was to study the optimum conditions of Pycnoporus sanguineus for producing ligninase. [Method] A strain of lignindegrading white-rot fungus was selected from 5 strains of collected fungi and its ligninase production and the optimum conditions for producing ligninolytic enzyme were measured. [Result] It could produce two kinds of ligninase with good thermal stability. Different temperatures, carbon sources, nitrogen sources, acidities, as well as the additions of surfactant had distinct influence on the development of lignin-degrading enzymes of the fungus. The optimum condition was drawn out：38℃, pH = 4.5, 10.0 g/L glucose, 1.0 g/L tartaric acid ammonium. [Conclusion] The aim of research was to provide a basis for lignin degradation in practical production.

Optimal Conditions for the Purification of Sesamin by Recrystallization

[Objective] Sesamin has been widely used in healthy food and medicines in recent years due to its prominent biological functions. This study was aimed to determine the optimal parameters for sesamin recrystallization, to obtain high-quality and high-purity sesamin. [Method] The effects of solid-liquid ratio, heating tempera- ture and cooling temperature on sesamin recrystallization were investigated by sin- gle-factor experiments and orthogonal array testing （ORT）. The purity of resulting sesamJn was investigated by HPLC, [Result] The optimal conditions for the purifica- tion of sesamin were solid-liquid ratio of 1：10, heating temperature of 45 ℃ and cooling temperature of 25 ℃. Under these conditions, the purity of sesamin reached 95.26%. [Conclusion] Recrystallization is an effective technique to purify sesamin from sesame meal. Moreover, HPLC is also an ideal method for analyzing the purity of sesamin.

Establishment of a Multiplex PCR System for Detecting Transgenic Ingredients from Citrus

[Objective] This study aimed to establish a multiplex PCR system for de- tecting transgenic ingredients from Citrus. [Method] Based on the pBI121 plasmid sequences published in GenBank and actin gene sequence of Citrus, the primers specific to CaMV35S promoter, NOS promoter, NOS terminator and actin gene were designed, to establish a multiple PCR system which could detect four types of sequences. In addition, orthogonal tests were performed to determine the optimal concentrations of all the components in PCR reaction system, as well as the optimal PCR cycle parameters. [Result] The optimal PCR reaction system should contain 2.5μl of 10xPCR buffer, 2.0μl of MgCI2 （25 mmol/L）, 2.0 μl of dNTP mixture （2.5 mmol/L of each dNTP）, 1.0 μl of actin gene primers （10μmol/L）, 1.0μl of 35S promoter primers （10 μmol/L）, 1.5 μl of NOS promoter primers （10 μmol/L） and 0.5 μl of NOS terminator primers （10μmol/L）, 0.1 μg of template DNA, 1.25 U of Taq DNA polymerase; ddH20 was added to the total reaction system of 25μl. The PCR reaction program consisted of pre-denaturing at 94℃ for 5 min; 31 cycles of denaturing at 94℃ for 30 s, annealing at 64.1℃ for 45 s and extension at 72℃ for 50 s; final extension at 72℃ for 10 min. The reaction system optimized with the orthogonal tests could detect as less as 0.1% transgenic component in the tested samples. [Conclusion] The MPCR detection system established in this study can meet the requirements in theory for detecting the genetically modified ingredients in Citrus or the deep-processed products.

Studies on the Super-high-yield Cultivation Techniques for Oats in Tibet

[Objective] The aim was to explore the optimal levels of different factors influencing oat yield in Lhasa, Tibet. [Method] Orthogonal test was conducted to analyze oat cultivation technology in Tibet. [Result] Qingyin No.2 and Baiyan No. 8 were proved the optimal species to be grown in Lhasa with optimal sowing quantity at 150-180 kg/hm2. Sowing term is an extremely significant factor affecting growing season, and species and N fertilizer are significant factors. Al factors have none significant effects on hay yield. [Conclusion] The research provides theoretical refer-ences and technological supports for large-scale planting.

Separation of picolines by dissociation extraction

The separation of the by-product (The volume fraction of 3-picoline is 68.472 2% and 4-picoline 26. 517 6% .) in the synthesis of pyridine by dissociation extraction wasstudied. Six separation conditions of the dissociation extraction-the kind and the dosage ofextractant and organic solvent, the concentration of the extractant and separation temperature-wereinvestigated. Different levels of each factor were chosen to form an orthogonal test of six factorsand five levels. The results show that the volume ratio of 3-picoline and 4-picoline in organicphase is the highest when 24 mL picolines are separated at 0 t by 2. 0 mol/L p-toluenesulfonic andn-heptane whose dosages are 40 mL and 48 mL, respectively. The effect of the separation isconsiderably improved with repetition test. This process of dissociation extraction has commendablepotential for industrial exploitation.

Parameters Sensitivity Characteristics of Highly Integrated Valve-Controlled Cylinder Force Control System

Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system still has problems, such as strong nonlinearity, and time?varying parameters. This makes HIVC force control very diffcult and complex. How to improve the control performance of the HIVC force control system and find the influence rule of the system parameters on the control performance is very significant. Firstly, the mathematical model of HIVC force control system is established. Then the mathematical expression for parameter sensitivity matrix is obtained by applying matrix sensitivity analysis(PSM). Then, aimed at the sinusoidal response under(three factors and three levels) working conditions, the simulation and the experiment are conducted. While the error between the simulation and experiment can’t be avoided. Therefore, combined with the range analysis, the error in the two performance indexes of sinusoidal response under the whole working condition is analyzed. Besides, the sensitivity variation pattern for each system parameter under the whole working condition is figured out. Then the two sensitivity indexes for the three system parameters, which are supply pressure, proportional gain and initial displacement of piston, are proved experimentally. The proposed method significantly reveals the sensitivity characteristics of HIVC force control system, which can make the contribution to improve the control performance.

Influence of Characteristics on Bending Strength of Layered Steel Fiber Reinforced Concrete

The influence of two main characteristics of steel fiber, the aspect ratio （Df） and volume fraction （ρf）, on the bending strength of Layered Steel Fiber Reinforced Concrete （LSFRC） is investigated by using orthogonal test. Via the variance analysis on the experimental results and trend analysis on the two characteristics, Df is found significantly related to the bending strength of LSFRC. The influence ratio is 63.3%. The bending strength of LSFRC increases if Df increases, makes better when Df reaches 100. ρf has ordinary influence on the bending strength of LSFRC. The influence ratio is 29.2%. Other characteristics, such as the shape of steel fiber and the mix proportion, have less influence. The best ρf contributing to the bending strength of LSFRC is 1.5 %. If ρf is greater than 1.5%, it has negative influence on the bending strength of LSFRC. So, ρf makes a limited contribution to the bending strength of LSFRC.

Effect of welding parameters on Al/Ti joint property in electron beam welding-brazing

The electron beam welding-brazing being used to join 5A06 Al alloy to TC4 Ti alloy decreases the formation of brittle intermetallic compound.Experiments were carried out to study the influence of electron beam welding parameters on the tensile strength of welds,based on an orthogonal test and analysis method.The welding parameters include beam current,welding speed,scanning figure,scanning frequency,figure size,beam offset and focus current.The optimum parameters for3 mm 5A06 Al alloy and 2 mm TC4 alloy were as follows：acceleration voltage was 60 kV,beam current was 11 mA,welding speed was 600 mm/min,focus current was 0 mA,scan figure was O,scanning frequency was 1 000 Hz and beam offset was 0.5 mm.The results show that the joints were with good appearance and quality welded by the optimum parameters.The successful joints could be gained and the maximum tensile strength of Al/Ti dissimilar alloy joints could be up to 222.61 MPa using electron beam welding-brazing.

Effect of austempering parameters on microstructure and mechanical properties of horizontal continuous casting ductile iron dense bars

In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters （i.e. austenitizing temperature and time, and austempering temperature and time） on microstructure and mechanical properties of LZQT500-7 ductile iron dense bars with 172 mm in diameter which were produced by horizontal continuous casting （HCC）. The results show that the major factors influencing the hardness of austempered ductile iron （ADI） are austenitizing temperature and austempering temperature. The fraction of retained austenite increases as the austenitizing and austempering temperatures increase. When austenitizing temperature is low, acicular ferrite and retained austenite can be efifciently obtained by appropriately extending the austenitizing time. The proper austmepering time could ensure enough stability of retained austenite and prevent high carbon austenite decomposition. The optimal mechanical properties of ADI can be achieved with the fol owing process parameters： austenitizing temperature and time are 866 ＆#176;C and 135 min, and austempering temperature and time are 279 ＆#176;C and 135 min, respectively. The microstructure of ADI under the optimal austempering process consists of ifne acicular ferrite and a smal amount of retained austenite, and the hardness, tensile strength, yield strength, elongation and impact toughness of the bars are HBW 476, 1670 MPa, 1428 MPa, 2.93%and 25.7 J, respectively.

Rolling motion behavior of rockfall on gentle slope:an experimental approach

The effects of slope surface material, slope gradient, block shape, and block mass conditions on rockfall rolling velocity were estimated with orthogonal test approach. Visual analysis shows that the importance of the factors is slope surface material > slope gradient > block shape > block mass. All the factors except block mass have the F value greater than the critical value, suggesting that these three factors are the key factors affecting the rockfall rolling velocity. Factor interaction analysis shows that the effect of the slope gradient relies largely on the slope surface conditions, and the block shape has little influence if the slope gradient is larger than a critical value. An empirical model considering the three key factors is proposed to estimate the rolling velocity, of which the error is limited to 5% of the testing value. This model is validated by 73 field tests, and the prediction shows excellent correlation with the site test. Thus, this analysis can be used as a tool in the rockfall behavior analysis.

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.

Optimization of investment casting process parameters to reduce warpage of turbine blade platform in DD6 alloy

The large warping deformation at platform of turbine blade directly affects the forming precision. In the present research, equivalent warping deformation was firstly presented to describe the extent of deformation at platform. To optimize the process parameters during investment casting to minimize the warping deformation of the platform, based on simulation with Pro CAST, the single factor method, orthogonal test, neural network and genetic algorithm were subsequently used to analyze the influence of pouring temperature, shell mold preheating temperature, furnace temperature and withdrawal velocity on dimensional accuracy of the platform of superalloyDD6 turbine blade. The accuracy of investment casting simulation was verified by measurement of platform at blade casting. The simulation results with the optimal process parameters illustrate that the equivalent warping deformation was dramatically reduced by 21.8% from 0.232295 mm to 0.181698 mm.