Main Structural Parameters Research Articles

Design and Experiment of a Harvesting Header for Wide–Narrow-Row Corn

Aiming to solve the problems of the large harvesting loss and low harvesting efficiency of wide- and narrow-row corn harvesting header in China, a method for the side installation of a header is proposed. A wide–narrow-row corn harvesting header with high working efficiency and low harvesting loss was designed. The collision energy balance equation of corn ears was established. The analysis shows that the kinetic energy change before and after the collision between the ear and the picking plate is the main cause of the shedding of and damage to corn kernels. Based on this, the main structural parameters of the corn harvesting header were designed. Based on the principle of Box–Behnken test, the response surface test was designed. The effects of the plant feeding speed, feeding angle, and rotation speed of a stem pulling roller on harvesting performance were analyzed. The best combination of working parameters was determined: The plant feeding speed was 1.08 m/s, the feeding angle was 52.46°, and the rotation speed of the stem pulling roller was 835.25 r/min. At this time, the grain damage rate was 1.09% and the grain loss rate was 0.14%. The corresponding parameters are verified by experiments. The results show that the grain damage rate was 1.12% and the grain loss rate was 0.14%. The optimization results are essentially consistent with the verification results, which meet the requirements of corn harvesting performance.

Selective laser sintering of amorphous nanoparticles: Molecular dynamics simulations

The paper investigates the process of liquid-phase sintering of amorphous iron-based nanoparticles by the method of molecular dynamics simulations. The classical molecular dynamics package LAMMPS was used for modeling. Visual analysis of the atomic configurations of nanoparticles during their rapid cooling revealed the self-purification effect of the particles. Partial pair correlation functions and coordination number distribution functions were used to analyze the atomic structure of nanoparticles after sintering. As a result of the analysis of the main structural parameters, which were obtained using the specified functions, differences in the atomic composition and structure of the volume and surface of nanoparticles were established.

Effects of Thermal-Moisture Coupled Field on Delamination Behavior of Electronic Packaging

Abstract Delamination failure is one of the most prevalent and serious reliability issues in micro-electronic packaging. To understand this phenomenon further, this study constructs an experimental test system consisting of a double cantilever beam (DCB) fixture, an MTS-Acumen microforce tester, and a temperature and humidity controller. The system is employed to investigate the effects of coupled moisture-thermal loading on the critical strain energy release rate (SERR) at the epoxy molding compound (EMC)/Cu leadframe (LF) interface of a very thin quad flat no-lead package (WQFN) assembly. A three-dimensional computational model with hygro-thermal loading conditions is developed to evaluate the moisture diffusion, thermal stress, and integrated stress of a multichip WQFN package under typical processing conditions and precondition tests. The validated simulation model is then applied with the virtual crack closure technique (VCCT) to investigate the fracture behavior at the EMC/Cu LF interface in the WQFN package. The effects of three design parameters on the SERR performance of the package are identified through a parametric analysis. Finally, a Genetic Algorithm (GA) optimization method is employed to examine the effects of the main structural design parameters of the WQFN package on its delamination reliability. The results are used to determine the optimal packaging design that minimizes the SERR and hence enhances the package reliability.

Tunable bandgap characteristic of various hexagon-type elastic metamaterials for broadband vibration attenuation

Inspired by the advantages of the hexagon lattices and auxetic metamaterials, the typical two-dimensional (2D) hexagon-type elastic metamaterials (EMs), that is, the concave, the convex, and the rectangular hexagon-type EMs, are presented for investigating the dynamic behavior systematically. Firstly, the lumped mass-spring models are used to construct the band structures, and the eigenmodes are obtained by solving the eigenvalue problem of motion equations to unveil the formation mechanisms of bandgap (BG). Note that the specific dispersion branches are characterized by eigenfrequencies with the eigenmodes presenting similar vibrational forms, rather than just ranking the eigenfrequencies from low to high. Furthermore, the dependence on the main structural parameters of the lumped mass-spring models is investigated to achieve tunability of the bandgap characteristics. Then, the continuum models are also established to study the formation of bandgaps as well as the propagation of waves based on eigenmodes and transmission. The comprehensive study of the physical mechanics of the unit cells is carried out, encompassing the analysis of iso-frequency contours, deformation fields, and mesh-independent analysis. Finally, both the numerical analysis and experimental validation demonstrate the effect of vibration attenuation on in-plane elastic waves, which has the ideal great agreement with the prediction of the band structures (the values of the frequency response functions are much less than -20 dB within the ranges of BGs). This research is expected to provide valuable insight into the design of vibration isolators, beams, plates, and other devices that are being renewed.

NSGA-II Algorithm-Based Structural Parameters of Electric Pulse Rock-Breaking Electrode Bit Multi-Objective Optimization

Abstract High-voltage electric pulse (HVEP) electrode bit has a considerable influence on the drilling and rock-breaking (RB) efficiency. HVEP electrode bit was systematically studied to optimize the structural parameters in order to improve RB efficiency. This paper analyzed the impact of main structural parameters on electric field strength (EFS) and depth of penetration (DOP) during high-voltage electric pulse drilling. A structural optimization method integrating back propagation (BP) neural network and genetic algorithm for HVEP electrode bit was proposed. The method mapped the complex nonlinear relationships among electrode distance, electrode cone angle, electrode grounding span, etc., and EFS and DOP by establishing a BP neural network model, and adopted the non-dominated sorting genetic algorithm-II (NSGA-II) to optimize the main structural parameters. The simulation data showed that the combined BP neural network/non-dominated sorting genetic algorithm-II (BP-NSGA-II) was an effective tool for optimizing the injection molding process. The multi-objective optimization of the structural parameters of the HVEP electrode bit based on the NSGA-II algorithm was crucial to direct the choice of the process parameters of the HVEP electrode bit, boost the RB efficiency, and lower the energy loss during drilling.

Kinematic analysis of the movement of the active knife cutter of chicory roots

Chicory roots are a valuable technical and strategically important crop for the leading sectors of the Ukrainian economy. The processing of raw materials from chicory roots allows to obtain energy (biofuel), food (coffee) and pharmaceutical (inulin) products. The low level of mechanization of harvesting root crops and, especially, harvesting both chicory and chicory root crops (significant losses, damage) does not allow to provide the needs of raw materials for its processing, or the necessary provision of the food industry of the Ukrainian economy and the fodder base of animal husbandry due to an increase in the amount of use root crops of chicory. One of the reserves for improving the performance of machines for harvesting chicory root crops is the improvement of the technological process of harvesting ginseng through the use of improved main working organs – a rotary ginseng cutter and a cutter of ginseng residues from the heads of root crops. The purpose of the work is to increase the indicators of the technological process of harvesting chicory root crops by developing and substantiating the parameters of the cutter's working organs. On the basis of the conducted theoretical analysis of the process of movement of the active cutter knife along the head of the root crop, analytical dependencies were developed that functionally describe the process of movement of the active cutter knife along the root crop head, which made it possible to substantiate the main structural and kinematic parameters of the active cutter knife. It has been established that the working length of the active knife of the cutter of the remains of burdock from the heads of root crops is in the range from 0.25 to 0.3 m, provided that the maximum permissible deviation of the vertical axis of the root crop from the axis of the row at the speed of movement of the burdock harvesting module is from 1.6 to 2.2 m /s and the speed of movement of the cutting edge of the blade of the active knife in the range from 0.3 to 0.8 m/s.

Theoretical substantiation of the device parameters for drying the green mass of essential oil crops in a vacuum drum dryer

Purpose. To substantiate theoretically the main structural parameters of the device for drying the green mass of essential oil crops in a vacuum. Methods. In the process of theoretical substantiation of the device for drying the green mass of essential oil crops in a vacuum drum dryer, the methods of technical analysis of the movement of the green mass along the blades and the inner surface of the drying drum, planimetry, and trigonometry were used. The dependencies for calculating the design parameters of the device were derived on the basis on algebraic methods. The analysis of the formulas was based on graphical dependencies constructed on their basis. Results. A preliminary experiment using straw mass on the SVB-10 vacuum drum dryer found that a grass bundle is formed in one complete rotation, the central part of which is difficult to dry. To prevent the formation of the grass tourniquet, it was proposed to use L-shaped blades attached to the inner surface of the drum. It was found that to ensure the turning of the green mass and the rational use of the drying drum space, the height of the blade should be equal the length of the L-shaped blade visor. Dependencies have been developed to calculate the angle between the canopy and the blade, the condition for the blade height, their rational number, and the maximum portion mass of green mass that can be loaded into the developed device. A general view of the device for drying green mass of essential oil crops in a vacuum drum dryer was also proposed. Conclusions. Due to the large internal friction angle and low thermal conductivity, it is advisable to use a drying drum with L-shaped blades attached to the inner surface of the drum, with the height of the blade equal to the length of the canopy. The use of L-shaped blades ensures uniform mixing of the green mass of essential oil crops during the rotation of the drying drum and prevents the formation of a harness. The number of blades, their geometric dimensions depend on the radius of the drying drum, the friction angle of the green mass of essential oil crops on the metal surface, the permissible technological gap, and the specified weight of the portion loaded into the vacuum drum dryer. Keywords: green mass of essential oil crops, vacuum, L-shaped paddle, vacuum drum dryer, drying drum, canopy, herbal bundle, drying, friction angle.

Multi-Methodological Geophysical Approach for Rapid and Non-invasive Structural Characterization of Infrastructures

In the context of health monitoring of structures/infrastructure, we propose a combination of different rapid and non-invasive experimental methods that allows the determination of the main structural parameters of an infrastructure. It is based on simultaneous acquisition of 20 minutes of seismic ambient noise with seismic arrays placed at different points of the infrastructure without diverting or blocking the traffic flow or interrupting the operation of a road infrastructure. The signals are analyzed using different analysis techniques such as standard spectral analysis (Fourier Amplitude Spectra, FAS), Frequency Domain Decomposition (FDD), Ambient Noise Deconvolution Interferometry (ANDI), and Non Parametric Damping analysis (NonPaDAn). These combined techniques were applied to two different types of viaducts: the Gravina bridge, located on the SS.655-Bradanica, and the Monticello viaduct on the SS.407-Basentana (Albano di Lucania), both located in the Basilicata region (Italy). The Gravina bridge is a newly constructed arch bridge whose structural parameters, evaluated using this approach, represent the zero-time reference point for further investigations on the temporal evolution of the structural parameters. The Monticello bridge is a multi-span viaduct built in the 1970s whose estimated structural parameters were compared to the various degrees of degradation observed on the girders. The application of different methods has facilitated and improved the interpretation of the results obtained, proving very promising for the estimation of the main vibrational modes, the associated mode shapes, the equivalent damping and the wave propagation velocities.

Influence of the Processes of Fluffing the Flax Stem Strips on the Structural Parameters of the Layer

Introduction. The efficiency of separating long flax fiber from the flax straw largely depends on the structural parameters of the layer of flax stems. Modern fluffers for flax strips create random distortions and intersection of the layer of flax stems under the pick-up drum. These disadvantages of existing machines are minimized in an experimental fluffer, in which a layer of flax stems moves over the pick-up drum with a kinematic mode indicator equal to one. Aim of the Article. The study is aimed at finding means and methods for preserving the structural parameters of the layer of flax stems when fluffing flax straw strips. Materials and Methods. Experimental studies were carried out according to existing and newly developed methods, and the analysis of flax fiber was carried out according to the current GOST standards. The experiments were carried out on the flax strips formed by the LC-4A flax harvester. After grass sprouted through the strips of flax stems, they were fluffed with the serial machine VL-3 and an experimental fluffer. For each variant, the necessary measurements of the main structural parameters of the stem strip and collection of samples for analysis were made before the unit passed and after fluffering the flax stem strip. The results of measurements and processing of samples were processed using the methods of mathematical statistics. Results. It was found that macro-bends of the original and processed flax strips were in all the experiments. At the same time, the range of changes in the curvature of the flax strip outside the cutoff frequencies expanded 2.3 times under the influence of the working tools of the serial tedder VL-3. The randomness of these pulsations was caused by an increase in the distortion and elongation of the flax stems in the strip by 6.0° and 6.9%, respectively. At the same time, the experimental fluffer produced the smallest changes in the structural parameters of the flax stem layer. The technological evaluation of the flax straw confirmed the advantages of the experimental fluffer in comparison with the serial VL-3, which has an average production of long fiber higher by 0.65% and 0.5 units of number. Discussion and Conclusion. The analysis of the obtained results indicates the practicability of fluffing flax strips by picking up and moving the stems from above the pick-up drum with its kinematic mode index equal to one.

Experimental investigation of the rotational characteristics of a novel hybrid laminated glass beam-column connection prototype

This article presents an experimental investigation of the rotational characteristics of a novel hybrid laminated glass beam-column connection prototype. The testing of small-scale prototype specimens is conducted to assess the effect of the main structural parameters such as glass pane thickness, interlayer and reinforcement properties on the rotational characteristics. To explore the possibility of using different lamination technologies for the realization of the joints, two different bonding technologies are considered separately: (a) autoclave and (b) UV-curing lamination. The specimens are subjected to a pair of self-equilibrated compressive forces up to failure in a custom-made setup. Digital image correlation (DIC) measurements together with strain gauges are used for tracking the kinematics of the main components. It was found that the prototype is able to develop a significant post-fracture and rotational capacity in a properly balanced combination of structural and material parameters. The results are presented in terms of moment-rotation (M - θ) curves, strains evolution in the steel and evolution of the crack patterns. Experimental observations suggest that depending on the choice of structural parameters three failure modes are possible: (a) crushing failure of the joint core, (b) plastic failure of the adjoining sections and (c) failure due to debonding of one of the bars in tension. It is concluded that one can achieve a desirable post-fracture and ultimate behaviour by properly balancing the structural and material parameters. Additionally, pull-out opening and tensile stresses in steel are measured at the interrupted section, revealing a transition in sectional behaviour from fully interrupted to a hybrid section over a certain transition length.

Design and Experiment of Grain Lifter for Sorghum Harvester

In order to solve the problems of grain lifter in sorghum harvesting, such as ear loss and serious crop leakage loss, combined with the physical and mechanical characteristics of sorghum, the segmented and reverse spiral grain lifter for sorghum harvesting and cutting table was developed, and the design method of the main structural parameters of the grain lifter was determined. The comparative test of the working effect of the clasp showed that the working effect of the cutting table with the clasp was better than that without the clasp, which effectively reduced the harvest loss of the cutting table. By using Box–Behnken experimental design method, the influence law of forward speed, tilt angle, and rotation speed of grain lifter on the rate of ear loss and harvest loss in sorghum harvesting was investigated. The regression mathematical model and response surface of the rate of ear loss and harvest loss and analysis factors were established, and the optimal working parameters of the grain lifter were determined. The forward speed was 0.8 m/s, the tilt angle of the grain lifter was 28°, and the rotation speed of the grain lifter was 330 r/min. Under these conditions, the spike loss rate was 2.01, the leakage loss rate was 2.19, and the error with the theoretical value was less than 3%, which proved the rationality of the optimized combination parameters. In the harvest of crooked and fallen sorghum, the grain lifter can effectively reduce the loss of sorghum head drop and lodging leakage, ensure the reliability of the cutting table, and achieve low loss and efficient harvest of sorghum.

Design and Experiment of Uniform Seed Device for Wide-Width Seeder of Wheat after Rice Stubble

When wide-width sowing wheat after rice stubble (WRS) in a rice-wheat rotation area, there is a problem of poor uniform of seed distribution. To solve the problem, this study designed the seed distribution plate (SDP) structure and optimized its critical structure parameters. Firstly, combined with the operating principles of the wide-width seeder and the agricultural standards for WRS, the main structural parameters affecting seed movement were determined by a theoretical analysis of seed grain dynamics and SDP structure. Secondly, the operational performance of six different structures of SDP under different structural parameters was compared using discrete element simulation technology. The structure of SDP most suitable for WRS wide-width seeding and the value ranges of key structural parameters that have a significant impact on the coefficient of the variation of seed lateral uniformity (CVLU) were determined. Finally, the pattern and mechanism of the influence of key structural parameters of SDP on the CVLU were analyzed. The optimum parameter combination was obtained and a field validation test was conducted on this. The results showed that the anti-arc ridge and arc bottom structure (S6) is more suitable for the agronomy standards of WRS wide-width seeding. The chord length of ridge, installation inclination, angle between the chord and tangent of the end of ridge line (ACT), span, and bottom curve radius are determined as the key structural parameters affecting the CVLU, and there is a lower CVLU (42.8%) when the ACT is 13°. The primary and secondary order of the influence of each factor on CVLU is the chord length of the ridge, span, installation inclination, and bottom curve radius. The corresponding parameter values after optimization are 140 mm, 40°, 75 mm and 50 mm, respectively. A field test was conducted on the SDP after optimizing parameters, and the CVLU was 30.27%, which was significantly lower than the CVLU before optimization.

Research on the influential factors related to the fuel leakage rate in the plunger-sleeve clearance of high pressure common rail system

In this study, a numerical model of the fuel leakage rate in the plunger-sleeve clearance of high-pressure common rail system was established based on graph theory. The transient clearance changes caused by the elastic deformation and the physical properties of the fuel along the flow direction within the plunger-sleeve were considered. This model realized the fluid–structure–thermal transient coupling during the leakage, and the accuracy was verified by comparing the calculated fuel leakage rate with the experimental data. Based on the main structural parameters of the plunger-sleeve, a three-level five-factor experimental calculation matrix was proposed using the D-optimal design method. The fuel leakage rates of all groups in the calculation matrix were obtained based on the fuel leakage rate numerical model, and the significant influencing parameters of the fuel leakage rate were determined using analysis of variance (ANOVA). The results indicate that the plunger diameter, sleeve external diameter, plunger-sleeve initial clearance and sealing length are significant parameters that affect the fuel leakage rate. In case of interaction between parameters, the interaction between the plunger diameter and sleeve external diameter, plunger diameter and plunger-sleeve initial clearance, and plunger diameter and plunger-sleeve sealing length contributed to a significant change in the fuel leakage rate. The influencing behavior of significant single parameters and significant interactions between parameters on the fuel leakage rate were revealed. The research outcomes can provide theoretical support for the optimization of the design of plunger-sleeve.

Distribution of field intensity and separation behavior of charged particles in the cascade electrostatic field

In this work, numerical simulations of straight-type and ladder-type cascade electrostatic fields consisting of three independent electrode plates were performed. The influence of the main structural parameters on the field intensity distribution and motion behavior of the charged particles in the electrostatic field were considered. The separation characteristics of charged particles in the two types of cascade electrostatic fields were comparatively analyzed. The simulation results were evaluated using high-speed dynamic image analysis and charge-to-mass ratio tests. The results show that the cascade distribution of electrostatic field intensity was more pronounced in the ladder-type structure than in the straight-type structure. The separation performance of different charged particles was better under the conditions of electrode plate spacing of 347 mm, electrode plate angle of 15°, and voltage gradient of 20 kV. The simulation results agreed well with the experimental results. This study provides new insights for realizing cascade triboelectric separation of minerals.

ANALYTICAL STUDIES OF THE PERMISSIBLE MASS OF THE CUTTER OF THE REMAINS OF THE HAULM FROM THE HEADS OF ROOT CROPS

Increasing the quality indicators of trimming the heads of chicory root crops is an urgent scientific task. An improved design of the cutter for the remnants of the gorse is proposed. The purpose of the research is to establish the functional dependence between the reduced weight of the pruner and the parameters of the work process of trimming the remains of burdock from the heads of chicory root crops. The method of developing deterministic mathematical models is given, which characterizes the change in the reduced mass of the trimmer of the remains of the root crops from the heads of root crops, made according to the "passive copier-spring-loaded knife" type, with the condition of no falling out and no damage to the root crops due to the process parameters. Based on the analysis, the main structural and kinematic parameters of the cutter's working bodies were established.Key words: root crops of chicory, remnants of sedge, trimmer, reduced mass of trimmer, copier speed.

A Planar Electromagnetic Actuator With Passive Adsorption for CubeSats Transport in a Weightless Environment

A planar electromagnetic actuator (PEA) with passive adsorption is proposed to transport multiple miniature satellites (CubeSats) in a weightless environment. It can realize reliable mover adsorption to the track and fast 2-Dof translational motion, even under the interference of external acceleration. Compared with the conventional layout of permanent magnets (PMs), the PEA with the structure of Halbach array can achieve higher force density. The magnetic equivalent circuits (MEC) method is applied to reveal the mechanism of electromagnetic performance improvement. An accurate electromagnetic force model is developed by combining the MEC and mirror magnetic charge methods to consider the positive effects of yokes on the PM operating point and airgap magnetic field distribution for PEAs with large airgaps. The influence of main structural parameters on adsorption and driving performances is analyzed. A kinetic model is derived to predict the mover velocity. A PEA prototype has been manufactured and tested to experimentally validate the improved models, electromagnetic performance, and motion characteristics.

SPECIAL FEATURES OF OPTIMIZATION DESIGN AND EVALUATION OF TECHNICAL RESOURCE FOR TRACTION GEAR TRANSMISSIONS OF RAILWAY ROLLING STOCK

The article highlights the peculiarities of optimization design for traction gear transmissions of railway rolling stock, aimed at determining the main structural parameters of corresponding paired gears and toothed wheels to increase their technical resource. The recommendations provide a formalized description of such investigations in the form of multidimensional optimization problems with constraints. Significant attention is given to the selection peculiarities of main variable parameters, primary criteria (related to reducing wear on tooth contact surfaces), and secondary numerical criteria (corresponding to functional constraints). The displacement coefficients of the gear and toothed wheel are considered as the main variable parameters, with a decisive impact on engagement parameters and characteristics. The main criterion, taking into account the focus on increasing the technical resource, is the minimization of the difference between the maximum coefficients of specific sliding on the feet of the lateral profiles of contacting teeth. Numerical functional constraints correspond to general design conditions for manufacturing and meshing of gear elements. The article elucidates the peculiarities of searching for optimal solutions using available generalized mathematical models that describe changes in the main criterion and existing functional constraints based on selected main variable parameters. It is also recommended to use constructed blocking contours based on these models to define the region of admissible solutions and find the corresponding optimization solution. For each variant of structural parameters of the paired gear and toothed wheel found during optimization design, the article suggests evaluating the respective changes in the technical resource according to the provided recommendations. The article presents the results of a comprehensive study of traction gear transmissions in various series of locomotives and electric trains, including assessments of increased technical resource achieved by using paired gears and toothed wheels with specified design parameters obtained through optimization design.

Effective Stiffness and Seismic Response Modification Models Recommended for Cantilever Circular Columns of RC Bridges, Second Part: Collapse Prevention Limit State

This paper aims to assess the structural overstrength (R), seismic behaviour factor (Q), and effective inertia factor (keff), of which the effective elastic stiffness (Keff) is a function, i.e., Keff (keff), of reinforced concrete (RC) cantilever columns with solid circular sections in urban bridges. The R and Q factors proposed in the design codes have been based mainly on an empirical basis. However, some studies suggest that, in the case of RC bridge columns, both factors are determined by a range of geometric and structural parameters. These results indicate that equations incorporating the main geometric and structural parameters of the columns, rather than the use of fixed values, are the appropriate method for estimating the values of R, Q and keff for the columns. Therefore, the results confirm the relation between R, Q and keff with the mechanical properties of the concrete, the aspect ratio length–depth, the axial load–strength ratio of a column, as well as its longitudinal reinforcement steel ratio. Finally, the research proposes models for estimating R, Q and keff that are recommended for the collapse prevention limit state of cantilevered circular columns of RC bridges.

Switchable magnetic dipole assisted double QBICs in an asymmetry four-leaf clover-shaped Ge2Sb2Te5 metasurface

Dynamically tunable metasurface resonators with high Q factors and excellent sensing performance still lack research. This paper proposes a dual-band symmetry broken induced quasi bound state in the continuum (QBIC) sensor in the near-infrared region based on an asymmetric four-leaf clover-shaped Ge2Sb2Te5 (GST) metasurface. The high-quality transmission spectrum can be tuned by switching the GST crystalline state. Two QBIC magnetic dipole resonances are excited at the amorphous GST state, QBIC Ⅰ (intracavity MD mode) and QBIC Ⅱ (intercavity high-order MD mode). Based on theoretical simulation, the refractive index sensitivity of the QBIC Ⅱ mode (318.05 nm/RIU) is enhanced higher than twice of the QBIC Ⅰ mode (134.03 nm/RIU) owing to the unique electromagnetic field properties. The ultra-high Q factors generated by the two MD resonance modes are 1.1 × 105 (QBIC Ⅰ) and 1.71 × 105 (QBIC Ⅱ) respectively for a small perturbation of the air hole offset distance D = 5 nm. By discussing the effect of the main structure parameters and the analyte thickness on the sensitivity, the optimal parameters are determined. The two strong QBICs supported by the a-GST metasurface are stable when the air hole’s offset from the unit center is at different directions and distances, indicating a good tolerance to fabrication requirements. These results provide a competitive switchable dual-band QBIC metasurface sensor, providing a potential route for tunable metadevices for functional sensing and dynamic control over signals.

Study on characteristics of phase-isolation caused by different classic axial flow swirlers in upward vertical gas-liquid two-phase flow

The characteristics of phase-isolation of annular flow caused by axial flow swirler are very critical for separation efficiency of axial inlet separator and accuracy of phase-isolation based measurement method. However, there are lack of comparative study among different types of swirlers and research focusing on characteristics of phase-isolation. In this paper, the phase-isolation characteristics caused by four different classic axial flow swirlers with the same main structural parameters were firstly experimentally studied in upward vertical gas-liquid two-phase flow. Five flow patterns were proposed after obvious evolution in phase distribution at downstream of the swirler, including gas-column flow, swirling annular flow, central bubble flow, central bubble-column flow, and variable diameter gas-column flow. According to the different phase-isolation characteristics, flow patterns downstream of the swirler were divided into stable phase-isolation, quasi-phase-isolation, and non-effective phase-isolation. The corresponding flow pattern maps were also obtained respectively. The experimental results also show that the swirler with good phase-isolation performance generally requires a larger pressure drop as the cost. Finally, the flow in the swirlers was studied numerically. It is found that although the outlet angle of the swirlers is the same, different types of swirlers will result in flow with different deflection angle, and eventually cause the different phase-isolation performance.