Orthogonal Experimental Design Method Research Articles

Multi-parameter screening study on the static properties of nanoparticle-stabilized CO2 foam near the CO2 critical point

The important role of nanoparticles (NPs) on foam stabilization under harsh geological conditions has been well recognized. In this paper, the Orthogonal Experimental Design (OED) method is adopted to investigate the synergy effects of six parameters, including NP concentration, surfactant concentration, oil concentration, salinity, temperature, and pressure, under five levels in the range of 0–0.2 wt%, 0.1–0.5 wt%, 0–4 wt%, 0–8 wt%, 20–60 °C, and 5.5–9.5 MPa respectively. K values and B values obtained in the OED experiments are employed to show the single parameter effect and the importance of each influential factor on foam static properties. It is concluded that system temperature and pressure, which has the highest B values of 22 mm and 18 mm on foam height results, are the dominant parameters on foamability, whereas temperature with B values of 80% on foam decay rate is the dominant factor on foam stability. It is observed when the system condition is close to the CO2 critical point, the foamability and stability of the NP-stabilized foam are much worse than under conditions far from the critical point. At last, optimal formulation of surfactant and NP concentration is proposed and validated for two geological cases of 45 °C and 55 °C with salinity and oil presence. It is expected the experimental technique, as well as the research results, reported in this paper could help the laboratory screening and formulation optimization of the complex NP-stabilized ScCO2 foam system.

Multi-objective optimization of a redundantly actuated parallel robot mechanism for special machining

Abstract. In order to improve the accuracy and efficiency of special machining for a complex surface, a 2RPU-2SPR (where R, P, U, and S stand for revolute, prismatic, universal, and spherical joints, respectively) over-constrained redundantly actuated parallel robot mechanism is proposed. And six performance evaluation indexes are established to ensure the working performance including workspace, motion/force transmission efficiency, stiffness, dexterity, energy efficiency, and the inertia coupling index. Furthermore, a collaborative optimal configuration algorithm is conducted based on an orthogonal experimental design algorithm and a multi-objective particle swarm optimization algorithm. On the basis given above, a simulation analysis of a multi-objective optimization is conducted. Compared with two traditional, intelligent optimization algorithms of a multi-objective particle swarm optimization algorithm and an orthogonal experimental design method, the improved collaborative multi-objective optimization algorithm has a better optimization effect.

Parametric study on the flutter sensitivity of a wide-chord hollow fan blade

In recent years, the hollow fan blades have been widely used to meet the demand for light weight and good performance of the aero-engine. However, the relationship between the hollow structure and the aeroelastic stability has not been studied yet in the open literature. In this paper, it has been investigated for an H-shaped hollow fan blade. Before studying the flutter behavior, the methods of parametric modeling and auto-generation of Finite Element Model (FEM) are presented. The influence of the feature parameters on the vibration frequency and mode shape (as the input of flutter calculation) of the first three modes are analyzed by the Orthogonal Experimental Design (OED) method. The results show that the parameters have a more remarkable impact on the first torsional mode and thus it is concerned in the flutter sensitivity analysis. Compared with the solid blade, the minimum aerodynamic damping of the hollow blade decreases, indicating that the hollow structure makes the aeroelastic stability worse. For the parameters describing the hollow section, the rib number N has the greatest influence on the minimum aerodynamic damping, followed by the wall thickness W5. For the parameters in the height of hollow segment, the aerodynamic damping increases with the increase of parameters M1 and M2. This means that reducing the height of the hollow segment is helpful to improve the aeroelastic stability. Compared with the impact of parameters in hollow section, the variation of aerodynamic damping caused by the height of the hollow segment is small.

Optimal design of drag reduction oscillators by considering drillstring fatigue and hydraulic loss in sliding drilling

Practice has proved that drag reduction oscillators can be used to decrease the axial friction and increase wellbore extension effectively in sliding drilling. However, the complicated mechanical behaviors of drillstring with drag reduction oscillators have not been revealed sufficiently, and there has no theoretical method to optimize drag reduction parameters. In this paper, an optimization design model of drag reduction oscillators is built with drag reduction efficiency as the target, and the mechanical model of drillstring with drag reduction oscillators is established by considering the friction nonlinearity. Further introducing the initial conditions, boundary conditions, and continuity conditions, the finite differential equation of drillstring vibration is obtained and solved. Next, combined with the oscillation propagation length and the installation position optimization models, the orthogonal experimental design method is applied to optimize the relevant parameters. In the optimization process, the constraint factors, including drillstring failure and hydraulic loss, are considered. Finally, the new model is applied to a field case study, in which the drag reduction effects of drillstring with and without oscillators are compared, and the impact of relevant factors on drag reduction are analyzed. The results show that the equivalent friction coefficient near the oscillator installation position is significantly reduced, whereas the hook load and weight on bit (WOB) are increased significantly with drag reduction oscillators. With the increase of amplitude or frequency, the propagation distance of the oscillator increases. The amplitude of vibration force and the number of oscillators are the two main factors affecting drag reduction efficiency. Three hydraulic oscillators with vibration amplitudes of 40 KN are recommended, and the drag reduction efficiency is 51.78%. However, excessively large oscillation amplitude may lead to drillstring failure and too many oscillators will increase the hydraulic loss a lot. Therefore, there are optimal values of oscillation amplitude and the number of oscillators. The research results are of significant guiding significance for optimal design and safety control of drag reduction oscillators in sliding drilling.

Multi-objective optimization of thermal-hydraulic performance in a microchannel heat sink with offset ribs using the fuzzy grey approach

The effect of four geometrical parameters (width of the offset ribs, depth of the offset ribs, incline angle of the offset ribs, and distance between the adjacent offset ribs) on heat transfer enhancement, friction loss, and performance evaluation criteria is analyzed on the basis of the orthogonal experimental design (OED) method and fuzzy grey relational analysis (FGRA). Results of FGRA reveals that depth is the most influential factor in heat transfer enhancement, width affects the friction loss more than others, whereas incline angle is the most significant factor in the performance evaluation criteria (PEC) of microchannel heat sink (MHS). A series of S-shaped staggered triangular offset ribs (SSTOR) is proposed to strengthen the performance of MHS based on the results of FGRA. The MHSs with novel offset ribs are studied at different Reynolds numbers from 100 to 1000 to find the optimal offset ribs. The average Nusselt number, pressure drop, PEC, and maximum temperature at the bottom wall of the MHS with five different novel offset ribs are discussed. The result shows that the optimal offset rib structure, SSTOR-45, can significantly improve the behavior of MHS with PEC = 1.36 at Re = 1000. Furthermore, this work offers an excellent reference for MHS design in the electronic package heat dissipation field.

Box Girder Optimization by Orthogonal Experiment Design and GA-BP Algorithm in the Gondola Car Body

Box girder is an important bearing and force transmitting component in the gondola car body; the rationality of its structure directly affects the life of the whole car body. In order to solve disadvantage of the traditional box girder optimization method, which mainly depends on design experience, the combined method of orthogonal experimental design and the genetic algorithm-back propagation (GA-BP) algorithm is used for the structural optimization of bolster beam in this paper. Nine groups of parameters were established by orthogonal experiment, which can give typical samples for GA-BP optimization. Then, the bolster beam is optimized by the GA-BP algorithm, and the new gondola car body model is established with the optimized parameters. The finite element analysis results show that the minimum stress is found by using the GA-BP algorithm, which is basically consistent with the simulation results. Finally, the results show that the combined method of orthogonal experimental design and GA-BP algorithm is feasible to the box girder optimization of the gondola car body. Meanwhile, the optimization results of bolster beam will provide a reference for the structural design of the heavy haul wagon body.

Numerical Modeling on Dynamic Characteristics of Jointed Rock Masses Subjected to Repetitive Impact Loading

A discrete element method code was used to investigate the damage characteristics of jointed rock masses under repetitive impact loading. The Flat-Joint Contact Model (FJCM) in the two-dimensional particle flow code (PFC2D) was used to calibrate the microparameters that control the macroscopic behavior of the rock. The relationship between macro- and microparameters by a series of uniaxial direct tension and compression numerical tests based on an orthogonal experimental design method was obtained to calibrate the microparameters accurately. Then, the Synthetic Rock Mass (SRM) method that incorporates joints into the calibrated particle model was used to construct large-scale jointed rock mass specimens, and the repetitive drop hammer impact numerical tests on SRM specimens with different numbers of horizontal joints and dip angle joints were carried out to study the damage evolution, stress wave propagation, and energy dissipation characteristics. The results show that the greater the number of joints, the greater the number of cracks generated, the greater the degree of damage, and the more energy dissipated for rock masses with horizontal joints. The greater the dip angle of joints, the less the number of cracks generated, the less the degree of damage, and the less energy dissipated for rock masses with different dip angles of joints. The impact-induced stress waves will be reflected when they encounter preexisting joints in the process of propagation. When the reflected stress waves meet with subsequent stress waves, the stress waves will change from compressional waves to tensile waves, producing tensile damage inside rock masses.

Experimental Study on Single Corner Cold Bending Mechanical Response of Laminated of PVB Interlayer Tempered Glass Panes and the Coupling Effect with Load.

The cold bending method is a type of curved glass curtain wall construction method that has been used in practical engineering for a short time. It has the advantages of simple operation, high efficiency and low cost. However, the mechanical response and properties of glass panes caused by cold bending have not been solved effectively. To study the mechanical response and the properties of cold formed laminated tempered glass panes after applying with a wind load, cold bending and load tests of 9 laminated tempered glass panes were conducted by the orthogonal experimental design method. The effects of cold bending curvature, glass pane thickness and interlayer thickness were considered. In this paper, the response law of cold bending stress to the curvature and the relationship among the influencing factors were analyzed. The variation process of stress, the deflection of cold-formed glass panes under uniform load and the characteristics affected by cold-formed stress and deformation were studied. The results show that the cold bending stress is distributed in a saddle shape, and the curvature has the greatest influence on the cold bending stress, followed by the thickness of the glass panes. The influence of the interlayer thickness is small. The maximum stress appears near the corner of the short side direction adjacent to the cold bending corner. The cold bending stress increases linearly with increasing cold bending curvature. The cold bending stress and deformation have little effect on the change process of the later stage load effect.

Pumping Well Layout Scheme Design and Sensitivity Analysis of Total Critical Pumping Rates in Coral Island Based on Numerical Model

Groundwater on small coral islands exists in the form of freshwater lenses that serve as an important water resource for local inhabitants and ecosystems. These lenses are vulnerable to salinization due to groundwater abstraction and precipitation variation. Determination of the sustainable yield from freshwater lenses is challenging because the uncertainties of recharge and hydrogeological characteristics make it difficult to predict the lens response to long-term pumping. In this study, nine pumping well layout schemes along a line are designed using the orthogonal experimental design method, and an optimal well layout scheme is determined by multi-index range analysis and comprehensive balance analysis method. The total critical pumping rates of the freshwater lens corresponding to different schemes are calculated by numerical simulation, and the sensitivity of the total critical pumping rates to hydrogeological parameters is analyzed. The results show that the calculation of the total critical pumping rates needs to be combined with the specific well layout scheme with consideration to the length of well screens, the number of wells and the distance between wells. The difference in total critical pumping rates between different schemes can be up to three times. The uncertainty of hydrogeological parameters has a great impact on the total critical pumping rates. Within the range of a 30% reduction in parameters, α and K are the key risk factors of pumping; within the range of a 30% increase in parameters, α, ne and K are the key risk factors; α-ne combined changes had the greatest impact. The management of freshwater lenses and the assessment of sustainable yield will continue to be important tasks for coral islands in the future, and this study can help with the sustainable exploitation of island freshwater lenses.

Preparation of Activated Carbon Derived from Waste Peanut Shells to Remove Dye from Water in a Batch System

Majority of peanut shells are thrown away or incinerated, which give rise to wasting resources and potential contamination. In this study, activated carbon (AC) from waste peanut shells were prepared with pyrolysis and K2CO3 activation process. The obtained peanut shell activated carbon (PSAC) were used to remove methylene blue (MB) in water. The orthogonal experiment design method was adopted to find the most suitable activation process. The modeling of adsorption isotherm and kinetic were conducted to explore the removal mechanism. The characterization results revealed that PSAC had a mesoporous structure with BET surface area of 735.6 m2/g and average pore diameter of 3.120 nm. Based on MB removal efficiency, the orthogonal experiments revealed that the order of the significant factor for PSAC preparation was activation temperature > activation time > impregnation ratio. The optimal parameters for preparing PSAC were at activation temperature 700 °C, activation time 90 min, and impregnation ratio 3:1. The equilibrium adsorption was simulated well by Langmuir isotherms model and the maximum adsorptivity was 615.92 mg/g. The adsorption kinetics followed the pseudo-second order model, which suggested that chemisorption was involved during the adsorption. Reusing experiments indicated PSAC had satisfactory reusability and stability for MB removal.

Research on energy harvesting properties of a diffuser-augmented flapping wing

This paper designed a diffuser-augmented flapping wing device. Based on the orthogonal experimental design and numerical method, it is aimed to simulate the impact of structural parameters on the power coefficient and energy harvesting efficiency and research the effect and prioritize of structural practices on flapping wing performance. The results show that the energy harvesting efficiency can be improved by 53.7% by selecting appropriate parameters. The performance of the power coefficient is sensitive to the variation of flange height and diffuse angle, and the efficiency is sensitive to the variation of inlet spacing and flange height. Besides, the energy efficiency of the diffuser-augmented flapping wing will be improved under unsteady upstream velocity.

Design and properties of seawater coral aggregate alkali-activated concrete

To adequately develop the application of marine resources for island construction and sustainability in the construction industry, this paper explores the feasibility of using alkali-activated materials (AAMs) as alternatives to ordinary Portland cements (OPCs) for the application in seawater coral aggregate concrete (CAC) structures. Artificial seawater, coral aggregates, and slag-based AAMs containing 5 wt.% silica fume and 15 wt.% fly ash, were mixed to develop the alkali-activated seawater coral aggregate concrete (AACAC), with the workability (slump), compressive and splitting tensile strengths being studied. The influence parameters, such as the total cementitious material content, water-to-binder ratio, and sand rate, were considered through Taguchi orthogonal experimental design method. The experimental results indicated that the most important factor herein for the compressive and splitting tensile strengths of the AACAC was the total cementitious material content. The analysis of range and variance demonstrated that an optimal mixture for AACAC was determined to be a total cementitious material content of 500 kg·m−3, a water-to-binder ratio of 0.60, and a sand rate of 55%. Then, this optimal mixture was adopted to analyze the effect of the replacement ratio of sea sand for coral sand (R s) on the workability, compressive and splitting tensile strengths of AACAC, and the cement-based CAC was selected as the reference. Finally, the microstructures of the paste-aggregate interface for the CAC and AACAC sliced specimens were detected by scanning electron microscopy (SEM). It can be concluded that increasing R s improved the workability of the AACAC, but exhibited a very slight effect on its mechanical properties. Additionally, the utilization of AAMs can effectively reduce the broken of the coral aggregate inside the concrete due to improved interfacial transition zone (ITZ) between the aggregates and the pastes, thereby exhibiting a higher splitting tensile strength than that of the cement-based CAC.

Mixing performance analysis of the novel passive micromixer designed by applying fuzzy grey relational analysis

In this paper, we performed a numerical study on a passive baffled T-micromixer with two parallel inlets. The baffled structure is applied to improve the contact surface of two liquid streams under peristaltic flow. This article proposes a comprehensive evaluation value Ma to evaluate the mixing ability of micromixers on the basis of mixing efficiency and pressure loss. The mixing performance of various micromixers is investigated at Re = 0.01. Then, the 16 cases based on the four geometrical parameters (inclined angle, depth, width, and distance between neighboring baffles) are selected by the orthogonal experiment design method. The optimal structure and the most important influence factor on the mixing process are analyzed according to fuzzy grey relation theory. Results showed that the fuzzy grey relational grades of the incline angle of baffles to the mixing performance are the highest. According to the proposed results and the relevant research, four novel S-type stagger baffles (STSB) are proposed and investigated in further work. The micromixers with STSB could acquire a high mixing ability value from 1.47 to 1.63 at Dc = 1e-11 m2/s. The optimal design, STSB-30, can obtain high mixing efficiency at 88.2%, whereas the base micromixer achieves only 38.9% at the same working condition. This work could provide a great analytical method for relational multi-factor study and the novel structure design about mixing performance problems.

Research on Dilution of Laser Cladding Assisted by Pulsed Current Based on Orthogonal Experiment

With characteristics of high cladding efficiency, small grain size and low porosity, follow-up feeding pulse current assisted laser cladding can realize online self-healing of cracks on the cladding layer and get a crack-free cladding layer. It is a very promising new laser cladding technology. In this study, effects of cladding parameters (laser power, scanning speed, powder feed rate, pulse current, pulse frequency and pulse width) on dilution rate of coating were discussed through a six-factor three-level orthogonal experimental design method. Results demonstrated that laser power, scanning speed and powder feed rate can influence dilution ratio greatly, while pulse current, pulse frequency and pulse width influence the dilution ratio slightly. Among the top three major factors, laser power can influence the dilution ratio mostly, followed by powder feed rate and scanning speed. The dilution ratio increases with the increase of laser power, scanning speed and pulse width, but it decreases with the increase of powder feed rate and pulse frequency. With the increase of pulse current, the dilution ratio decreases firstly and then increases.

Image reconstruction of electrical capacitance tomography based on optimal simulated annealing algorithm using orthogonal test method

Electrical capacitance tomography (ECT) is a visualization measurement method for two-phase flow. Imaging permittivity distributions using electrical capacitance tomography has always been one of the most significant issues studied by scholars, and the algorithm will have a great impact on the accuracy of image reconstruction result. This paper applies simulated annealing (SA) algorithm to image reconstruction in ECT. However, some parameters of SA algorithm need to be optimized in order to obtain better reconstructed images in ECT. The influence of different parameter values in SA algorithm for image reconstruction in ECT is studied, and a set of optimal parameters of the SA algorithm is obtained based on the orthogonal experimental design method in this paper. At the same time, simulation and static experiments are conducted. Reconstructed images by SA algorithm with optimized parameter are compared with the linear back projection (LBP) and Landweber iterative algorithms. The results show that better images can be obtained for typical oil-gas two-phase flow using SA algorithm. The quality and shape fidelity of reconstructed image for the central object are obviously improved.

Influence of structure and material on the vibration modal characteristics of novel combined flexible road wheel

Aiming at the independent development of tracked vehicles, it is urgent to improve its mobility, passability and ride comfort, a new type of flexible road wheel with a “wheel-hinge-hub” combined structure is proposed in this study. The vibration model characteristics of the flexible road wheel were studied by the combination of numerical simulation and experiments. The superelasticity of rubber is obtained through uniaxial tensile experiment of the material and a detail three-dimensional nolinear finite element model of the flexible road wheel is established through finite element software ABAQUS. The free vibration equation of the flexible road wheel is solved by Lanczos vector direct superposition method, and its predicted modes and natural frequencies are compared with experimental results, which verifies the accuracy and reliability of the established finite element model. On this basis, the effects of various key structural or material factors on the natural frequencies of the flexible road wheel are studied using orthogonal experimental design method. Besides, the vibration modal characteristics of the flexible road wheel are also compared with those of the rigid road wheel. The research results provide a theoretical basis for the vibration and noise reduction of flexible road wheel.

Study on the microscopic mechanism and optimization of dust suppression by compounding biological surfactants

In order to solve the problem of reducing the surface tension of pure water used in some spray dust reduction equipment, this study analyzed the action mechanism of the green biodegradable dust suppressant on coal dust from a microscopic point of view. Using orthogonal experiment design and response surface analysis method, the surface tension change of the green biodegradable composite dust suppressant and its influence on the wettability of coal dust is studied, several biological surfactants are added to water in nine groups in different proportions to prepare dust suppressants with the same total concentration. Through nine sets of sedimentation experiments with different configuration ratios, it is concluded that each set of compound dust suppressants can improve the wetting speed of coal dust to varying degrees. In the infrared spectroscopy experiment, we analyze the microscopic interaction mechanism of coal dust, compare the wettability of anthracite coal samples before and after treatment with the same quality dust suppressant through the change of functional groups. The internal mechanism of the biodegradable dust suppressant is explained from a two-dimensional curve, the low hydroxyl transmittance means high content, which effectively increases the hydrophilic groups on the surface of coal dust, thereby accelerating the wetting speed. The surface tension experiment showed that the use of compound reagents had a good synergistic effect. The lowest surface tension of the biodegradable dust suppressant is 28.515 mN/m in nine groups. Through response surface analysis method, the study finds the optimal value of the wetting speed of the dust suppressant, obtains the best ratio of each reagent in this new dust suppressant by using Design Expert 11.0. The optimal ratio is calculated as: 0.129 ml rhamnolipid, 0.044 ml lactone sophorolipid and 0.029 g surfactin per 100 ml of dust suppressant, the shortest wetting time is 31.777 s. • A biological compound dust suppressant with excellent wetting effect was prepared. • The hydrophilic functional groups on the surface of coal dust was changed by the composite dust suppressant. • The lowest surface tension of the biodegradable dust suppressant is 28.515 mN/m. • The optimal ratio of the dust suppressant is rhamnolipid 12.9%, lactone sophorolipid 4.4%, Surfactin 2.9%.

Optimize solid‐state synthesis ofP2‐Na0.67Ni0.33Mn0.67O2cathode materials by using the orthogonal experimental design method

Optimize solid‐state synthesis of<scp>P2‐Na₀</scp>_.<scp>₆₇Ni₀</scp>_.<scp>₃₃Mn₀</scp>_.<scp>₆₇O₂</scp>cathode materials by using the orthogonal experimental design method

Optimization of Kiloampere Peltier Current Lead Using Orthogonal Experimental Design Method

Reducing heat leakage is crucial for the development of practical superconducting devices. In this work, orthogonal experimental design method is first used to optimize the design of hundred-ampere and kiloampere Peltier current leads (PCLs). Geometry and arrangement of Peltier materials and conductive materials of the current lead are analyzed. Through our simulation, we find that the coupling effect between the radius of Bi2Te3 (r2) and the length of Bi2Te3 (L2) has the greatest effect on the heat leakage of PCLs at the cold end for both PCLs. Furthermore, numerical simulations suggest that the lowest heat leakage at the cold end (approximately 30.0 W/kA) is at the same level for both hundred-ampere and kiloampere PCLs. If taking the heat dissipation area at the hot end into account, multiterminal solutions are better solutions for kiloampere current leads.

Experimental Study of Low Temperature Performance of Porous Asphalt Mixture

Porous asphalt mixture can be used as a road surface paving material with the remarkable advantage to prevent water accumulation and ponding. However, the performance of porous asphalt mixture in low temperature environment has not been thoroughly investigated, and this forms the subject of research in the present study. The mineral aggregate gradation of porous asphalt mixture was designed based on Bailey method, and the low temperature performance of porous asphalt mixture was studied by means of the low temperature bending test. The factors affecting the low temperature performance of porous asphalt mixture were analyzed through the orthogonal experimental design method, and the effects of porosity, modifier content, aging condition, and test temperature on the low temperature performance of porous asphalt mixture were evaluated. The results showed that the modifier content was the most important factor affecting the low temperature performance of porous asphalt mixture, followed by the test temperature, while the porosity and the aging condition were the least. Among the three performance evaluation indicators, namely the flexural tensile strength, maximum bending strain, and bending stiffness modulus, the maximum bending strain had the highest sensitivity to the porosity. It can be seen from the single factor influence test of porosity that there existed an approximately linear relationship between the maximum bending strain and the porosity of porous asphalt mixture, and the maximum bending strain decreased with increasing porosity. Furthermore, in order to ensure the good working performance of porous asphalt mixture in low temperature environment, the porosity should also satisfy the required limits of the maximum bending strain.