Bench Test Results Research Articles

Optimizing of selective catalytic reduction urea injection and NOx conversion analysis of diesel engine based on higher-order physical model and sequential quadratic programming algorithm

In order to maximize the NOx conversion rate and minimize NH3 slip in the diesel selective catalytic reduction (SCR) system, first, the high-order SCR model was simplified and solved using the trapezoidal method and second-order backward difference formula, while the chemical reaction parameters were optimized using the Gauss-Newton method. The results of the engine bench test show that the mean absolute errors of NH3 and NOx concentrations under steady-state operating conditions were 2.67 ppm and 1.72 ppm, respectively, and 5.46 ppm and 42.50 ppm under severe operating conditions. Second, urea injection rate is optimized based on a high-order model combined with the sequential quadratic programming (SQP) algorithm. The change in NOx conversion rate at different temperatures and air speeds is analyzed, and the results show that the NOx conversion is best at 650 K and 29,000 h⁻1. Third, the experiment validation show that the optimal NH3/NOx ratio is 0.69 at 554 K and 54,200 h⁻1; 0.8; and 1.37 at 746 K and 116,700 h⁻1. Finally, this paper simulates and analyzes the SCR emission characteristics at different temperatures and air speeds when the upstream NOx concentration is 1,000 ppm.

Optimization Design and Experimental Study of Solid Particle Spreader for Unmanned Aerial Vehicle

This study designed and investigated a solid particle spreader, as well as parameter optimization and experimental for a groove wheel, to mitigate the problems of low uniformity and poor control accuracy of solid particulate material UAV spreading. The discrete element method was used to simulate and analyze the displacement range and stability of each grooved wheel at low speeds. Furthermore, orthogonal regression and response surface analyses were used to analyze the influence of each factor on the stability of the discharge rate and pulsation amplitude. The results showed that the helix angle, sharpness, and length of the groove significantly influenced the application performance, whereas the number of grooves had no significant influence. The groove shape was eccentric, the helix angle was 50°, the length was 35 mm, and the number of grooves was 7. Additionally, the bench test results showed that in the range of 10–60 rpm, the relative deviation of the discharging rate between the simulation and bench test is from 0.47% to 10.39%, and the average relative deviation is 3.93%. Between the groove wheel rotation speed and discharge rate, R2 was 0.991, and the adjustable range of the discharge amount was between 3.68 and 23.43 g/s. The minimum and maximum variation coefficients of the average discharge rate among individual applicators were 1.01% and 2.79%, respectively, whereas the standard deviations were 0.09 and 0.46 g/s, respectively. In conclusion, the discharge stability and adjustable range of the spreader using the optimized groove wheel satisfied the requirements for solid particulate material discharge.

USE OF TUBING COATINGS AND SCALE INHIBITORS TO PREVENT SCALING

The problem of formation of inorganic scaling in tubing is a common problem in oil production processes. The formation of salts on the inner surface of the tubing leads to a significant narrowing of the flow section of the pipe. An urgent task is to find methods, the use of which will either prevent or reduce the formation of inorganic scaling on the walls of pipes. Methods of removing scaling from the tubing are expensive, time consuming, and require shutdown of the oil production facility. Therefore, it is preferable to use methods for preventing salt formation in tubing. Methods of preventing the processes of scaling in the tubing include physical, chemical and technological. The most common method of preventing scaling is the use of scale inhibitors (chemical method). The use of internal protective pipe coatings (technological method) as a measure to prevent the formation of inorganic scaling on the walls of the tubing is a promising, but not fully studied method. The use of coatings is promising, since in addition to the potential reduction in the formation of scaling on the walls of pipes, their main function is corrosion protection.One of the methods of preventing salt formation in the tubing may be the integrated use of internal protective coatings of the tubing and scale inhibitors. But, since this method is not universal, an individual selection of the most effective coating-inhibitor combination will be required for each oil production facility. Selection of an effective coating-inhibitor combination using pilot field tests is an expensive and time-consuming procedure, therefore, it is necessary to develop a laboratory method to solve this problem. The article proposes a method that makes it possible to evaluate the effectiveness of the complex use of protective coatings and scale inhibitors to prevent the formation of inorganic salts on the inner surface of tubing in laboratory conditions. The results of bench tests for 9 grades of protective coatings and for 6 grades of scale inhibitors (in different dosages) are presented.

Variable impedance control for synchronizer position tracking based on gain scheduling

Achieving fast and stable synchronizer position tracking control can greatly improve the power and comfort of transmission shifting. In order to further improve the shift speed and stability of the synchronizer, this article takes the synchronizer control of a three-speed seamless transmission as the research object and proposes a variable impedance control method based on gain scheduling. Firstly, dynamic models of the shift actuator and synchronizer was established. Then, an impedance outer loop controller and a position inner loop controller were designed. In the impedance outer loop, adjust the synchronizer reference position based on the difference between the reference shift force and the actual shift force. At the same time, based on the actual control requirements of different motion stages of the synchronizer, the optimal impedance control parameters for each stage are selected for gain scheduling control. In the position inner loop, a prescribed performance-active disturbance rejection control is adopted, which solves the problem of system disturbance while ensuring the instantaneous performance of position tracking. Finally, simulations and bench tests were conducted on the position tracking control of synchronizer. The simulation and bench test results show that the control strategy proposed achieves fast and stable synchronizer position tracking, with superior control performance, which preliminarily verifies the effectiveness of the control strategy.

Design and Testing of a Branched Air-Chamber Type Pneumatic Seed Metering Device for Rice

To meet the diverse seeding requirements of super hybrid rice, common hybrid rice, and conventional rice—which vary from 1 to 3 seeds, 2 to 4 seeds, and 5 to 8 seeds per hole, respectively—this study developed a branched air-chamber type pneumatic seed metering device for rice. The device utilizes an air chamber control board to manage the branched air chamber casing, enabling precise adjustments to the seeding quantity. This study presents a theoretical analysis of the seed metering device’s operation and its critical components. Structural parameter optimization was conducted using Ansys-Fluent (2021 R1) software, followed by multi-objective optimization of operational parameters through bench testing. Simulation results indicated that optimal vacuum pressure in the seed metering disc pores reached a maximum of 857 Pa with a chamber depth of 22 mm, an angle of 100°, and a cavity depth of 25 mm, achieving a minimal coefficient of variation of 0.86%. Bench test results showed that for seeding targets of 1 to 3 rice seeds per hole, the optimal operational parameters were: two openings, a working vacuum of 1355 Pa, and a rotor speed of 32.78 r/min, resulting in a missed seeding rate of 4.70%, a qualification rate of 85.81%, and a re-seeding rate of 9.49%. For targets of 2 to 4 seeds per hole, the best parameters included three openings, a working vacuum of 1357 Pa, and a speed of 32.87 r/min, with a missed seeding rate of 4.60%, a qualification rate of 85.59%, and a re-seeding rate of 9.81%. For 5 to 8 seeds per hole, optimal parameters were six openings, a vacuum of 1339 Pa, and a rotor speed of 31.07 r/min, yielding a missed seeding rate of 4.09%, a qualification rate of 87.27%, and a re-seeding rate of 8.64%. These findings demonstrate that the branched air-chamber type pneumatic seed metering device effectively meets the varied direct seeding requirements of rice, enhancing the adaptability of pneumatic seed metering devices to different seeding quantities in rice and potentially informing the design of pneumatic seeders for other crops.

Study on a Novel Reseeding Device of a Precision Potato Planter

In order to address the problem of a high miss-seeding rate in mechanized potato planting work, a novel reseeding device is designed and analyzed. Based on dynamic and kinematic principles, the seed potato’s motion analysis model in the seed preparation process was constructed. The analysis results indicate that the seed preparation performance is positively related to the seed preparation opening length l1 and inclination angle of the seed-returning pipe θ. Then, the potato’s motion analysis model in the reseeding process was constructed. The analysis showed that the displacement of seeding potatoes in the horizontal direction ds is influenced by the initial seeding potato’s speed , dropping height hs, and the angle between the seeding pipe and the horizontal ground βs. The horizontal moving distance xr of the reseeding potatoes is influenced by the angle between the bottom of the reseeding pipe and horizontal ground βs2, the distance from its centroid to the reseeding door d, and the dropping height of the potato hr. The analysis results indicated that the reseeding potato can be effectively discharged into the furrow. Then, a prototype of a reseeding control system was constructed based on the STM32 microcontroller, electric pushers, and through-beam laser sensors. The simulation analysis was conducted to verify the theoretical analysis by using EDEM2020 software. The simulation results indicated that with the increase in the seeding chain speed, the seed preparation success rate initially increased slowly and then decreased gradually. The seed preparation performance can be increased by increasing the seed preparation opening length or decreasing the seed-returning pipe inclination angle. The impact on the successful seed preparation rate is ranked by significance as follows: seed preparation opening length > seed-returning pipe inclination angle > chain speed. Then, the prototype reseeding device and the corresponding seed metering device were manufactured and a series of bench tests and field tests were conducted. The bench test results showed an average successful seed preparation rate of 93.6%. The average qualified-seeding rate, miss-seeding rate, and multi-seeding rate in the field test were 89.6%, 2.46%, and 7.94%, respectively. This study can provide a theoretical reference for the design of potato reseeding devices.

Research on size effects in fracture properties and residual life prediction for high-speed train axles

As critical load-bearing components of high-speed trains, the design and evaluation of axles primarily adhere to the principle of infinite life, supplemented by systematic flaw detection to ensure their operational safety. The establishment of detection intervals heavily depends on damage tolerance analysis informed by fracture mechanics. The size effect has a great influence on the fracture mechanical properties of materials, and how to accurately assess the remaining life considering the dimensional effects has been an open question in terms of safety in the railroad industry. Consequently, this research focuses on full-scale axle crack propagation tests, exploring the fracture mechanics properties critical to the life analysis of full-scale axle cracks under very high cycle fatigue (VHCF) condition. The findings demonstrate that size effects profoundly affect the fatigue fracture properties of high-speed train axles, especially regarding fatigue crack growth thresholds. Importantly, within the stable growth region, variations in fatigue crack growth rates across different scales prove to be minimal. Subsequently, a finite element model of the full-scale axle was established using the fatigue crack growth rate curve derived from experimental data. The validity of this FEA model was confirmed through bench test results, and predictions of the residual life for axles with cracks were formulated. This comprehensive analysis provides the foundation for developing an ultrasonic detection interval schedule for axles.

Design and Testing of Electric Drive System for Maize Precision Seeder

To improve the expandability, seeding accuracy, and operating speed range of the electric drive system (EDS) of precision seeders, this study constructed an EDS based on a controller area network (CAN) bus and designed a motor controller based on a field-orientated control (FOC) algorithm. Full-factorial bench and field tests based on seed spacing (0.1, 0.2, and 0.3 m) and operating speed (3, 6, 9, 12, and 15 km/h) were carried out to evaluate the performance of the EDS. The results of bench tests showed that seeding quality varied inversely with operating speed and positively with seed spacing. The average quality of feed index (QFI) at 0.1, 0.2, and 0.3 m seed spacing in bench tests was 88.38%, 96.67%, and 97.36%, with the average coefficient of variation (CV) being 20.13%, 16.27%, and 13.20%. Analysis of variance confirmed that both operating speed and seed spacing had a significant effect on QFI and CV (p < 0.001). The analysis of motor rotational speed accuracy showed that the relative error of motor rotational speed above 410 rpm did not exceed 2.24%, and the relative error had less influence on the seeding quality. The average QFI was 85.93%, 95.91%, and 96.24%, with the average CV being 21.12%, 15.50%, and 16.49% at 0.1, 0.2, and 0.3 m seed spacing in field tests. The methods and results of this study can provide a reference for the design and optimization of the EDS in a maize precision seeder and provide an effective solution for the improvement of maize yields.

Experimental and simulation study on lean combustion characteristics of passive pre-combustion chamber ignition boosted GDI engine

In order to verify the potential application of passive pre-combustion chamber technology in commercial GDI engines, the efficiency characteristics, combustion characteristics (CA50, Knock Index and COV) and emission characteristics of a pre-combustion chamber ignition engine in a boosted environment were studied by three-stage injection strategy to form a lean burn environment (λ = 1.3). A 3D simulation model of pre-combustion chamber ignition engine is established. Combined with the engine bench test results, the process of intake, mixture formation, combustion and emission generation under different working conditions is simulated by simulation method. The development process of TKE (turbulent kinetic energy), air-fuel ratio, temperature and combustion emissions in the main/pre-combustor is studied. It is found that under high load conditions in boosted pre-combustion chamber engine, the average knock index can be controlled between 2 and 3.4 bar, and the COV can be controlled between 3% and 3.5%. The indicated thermal efficiency reaches over 40% within the load range of IMEP from 10 to 14 bar. When the load increases, NOx and soot emissions show a downward trend, the HC and CO emissions slight increase. The pre-combustion chamber engine exhibits a tumble intake pattern around the cylinder axis perpendicular to the cylinder axis. The TKE reaches its maximum value 20 CAD before the top dead center and then rapidly decreases. The use of a three-injection strategy can form a uniform stratified mixture at the ignition moment. The fuel air equivalence ratio in the ignition area of the pre-combustion chamber is 0.8–0.9, slightly higher than the average fuel air equivalence ratio of 0.75.

Analysis of the Newest Design of Axial Piston Hydraulic Machines with Reduced Friction Losses and Leaks

Problem. Analysis of modern achievements in the field of volumetric hydraulic drives to improve the technical level of construction and road machines. Goal. Study of the design of the latest foreign development related to the improvement of the technical level of axial-piston volumetric hydraulic machines, in particular pumps and hydraulic motors according to the scheme of Innas floating cylinders. This design, according to the proposal of its inventors, is intended to work as pumps with a flow of up to 7400 l/min or hydraulic motors with a working volume of up to 5000 cm3 at a pressure of up to 50 MPa. Methodology. Analysis of the results of comparative bench tests of the Innas axial piston pump of the latest development and volumetric hydraulic machines of various designs, in particular axial and radial piston, as well as gear ones. Results. According to the results of comparative tests, the new design of the Innas axial-piston pump is significantly ahead of other serial hydraulic machines in terms of efficiency. The total efficiency value of 96 % achieved in the Innas pump shows the promise of such hydraulic machines. Originality. Analysis of the results of experimental studies with the determination of the features of the structures of hydraulic machines in terms of volumetric and hydromechanical power losses. It is concluded that Innas hydraulic motors can be used in trailing volumetric hydraulic drives with hydraulic power amplifiers, for which the characteristic of friction in the displacement mode is the main one from the point of view of the accuracy of the execution of the specified control signals. Practical value. The given materials are useful for specialists in the field of mechanical engineering, in particular, the design of volumetric hydraulic drives for construction and road machines

ЗАЩИТНЫЕ СВОЙСТВА МОДИФИЦИРОВАННЫХ БИТУМНЫХ ПРАЙМЕРОВ ДЛЯ ПРОТИВОКОРРОЗИОННОЙ ЗАЩИТЫ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ И ОБОРУДОВАНИЯ

In order to protect agricultural machinery from atmospheric corrosion during the nonworking period, it is possible to use bitumen primers (BP), which are compositions of petroleum bitumen with the addition of solvents and, possibly, other additives. The protective properties of compositions based on the bitumen primer "Orgkrovlya No. 1" diluted with white spirit with modifying additives on samples of 08kp steel were studied in the work. Accelerated corrosion tests in 0.5 M NaCl solution showed the following: dilution of BP with 40 wt. % white spirit when applied in one layer leads to a decrease in the protective efficiency to 75%, 67 wt. % - to 37%; the introduction of additives (5 wt.%) of P2 paraffin into the diluted BP with 40 wt. % white spirit increases its protective efficiency (Z) to 98%, KO-SZhK - up to 87%, Emulgin - up to 94%; When diluting BP with 67 wt.% white spirit, the maximum Z = 60% is provided by the addition of 1 wt.% drying oil +1 wt.% POOM. Accelerated tests in the G-4 heat and humidity chamber and the salt spray chamber showed the best results for BP coatings diluted with 40 wt.% white spirit and with the addition of 5 wt.% P2 paraffin. The highest values of protective efficiency in the G-4 heat and humidity chamber for BP diluted with 67 wt.% white spirit are provided by coatings with 2 wt.% drying oil (Z = 97%), 5 wt.% POOM (Z = 97%), 1 wt.% drying oil +1 wt.% POOM (Z = 96%). According to the 9-month results of full-scale bench tests of modified BP diluted with 40 wt.% white spirit, the best results are provided by the coating with the addition of 5 wt. % paraffin P2 and Emulgin. These 2 additives effectively protect steel in a concentrated solution (200 g/l) of mineral fertilizer borofoska.

Study on the synergistic control of nitrogenous emissions and greenhouse gas of ammonia/diesel dual direct injection two-stroke engine

This study developed a numerical model for an ammonia/diesel dual direct-injection two-stroke engine and validated it based on engine bench test results. The engine combustion and emission characteristics were discussed under the cases of different injection parameters, intake temperatures, and exhaust gas re-circulation (EGR) rates. The findings indicate that altering the injection angle of ammonia and diesel sprays impacts the in-cylinder swirl and the ignition timing of the ammonia spray, consequently affecting the heat release phase of ammonia combustion. A suitable arrangement spray plumes can effectively reduce the emissions of unburned ammonia and greenhouse gas (GHG), while increase the emissions of NOx. On the other hand, higher intake temperatures can increase the average in-cylinder temperature, reducing unburned ammonia, N2O and GHG emissions. However, it also results in greater NO emissions, which can affect fuel economy negatively. Furthermore, the use of EGR technology can reduce the combustion temperature, thereby lowering the emission of nitrogen-based pollutants, but it also reduces ammonia combustion efficiency. By simultaneously applying the three aforementioned technologies within a certain range of conditions, it is possible to effectively synergize and control nitrogenous emissions and GHG while maintaining high thermal efficiency of ammonia/diesel dual direct injection engines.

Possibility assessment for using protective coatings and polymer materials on tubing to prevent inorganic scaling on the inner surface of pipes

AbstractThe inorganic scaling in wells is a common problem faced by mining companies. At present, the use of protective coatings for tubing as a measure to prevent or reduce the formation of inorganic scale deposits on pipe walls has not been fully studied. To use protective coatings as a measure to counteract the deposition of inorganic salts, it is necessary to develop a method that allows assessing the ability of coatings, as well as polymer and metal materials, to prevent the formation of inorganic scale deposits on the inner surface of pipes.The article proposes a method for assessing the ability of protective coatings to resist the inorganic scaling on the inner surface of tubing. The proposed assessment method allows to make an informed decision on the advisability of using internal protective coatings of tubing to prevent (or reduce) the formation of inorganic scale deposits. The authors consider design features of a test bench for assessing the resistance of coatings to inorganic scale deposits, which allows to simulate the conditions for the formation of scale deposits that are as close as possible to the real conditions of oil production facilities. The article presents the results of bench tests of nine coating samples, two polymer samples and one sample made of St 40G2 steel. To assess the effectiveness of using tubing with an internal anti-corrosion coating as a measure to combat scale deposits, additional research is required to assess the possibility of complex use of coatings in conjunction with other methods of preventing processes of inorganic scaling. Thus, the authors developed the Bench for assessing the resistance of protective coatings of tubing to inorganic scale deposits. A dynamic testing technique is proposed to evaluate the resistance of protective coatings to inorganic scale deposits. Based on the presented results, conclusions were drawn about the possibility of using protective coatings on tubing as a measure to prevent the formation of inorganic scale deposits on the inner surface of the tubing.

Numerical simulation method of seed pelletizing: Increasing seed size by powder adhesion

Seed pelletizing can effectively increase the seed size. However, observing the microscopic process of seed pelletizing using physical tests is challenging. This study used the discrete element method (DEM) to simulate the process. Discrete elemental simulation models and contact parameters of seed and powder had been determined by particle scaling theory and parameter calibration tests, respectively. The contact model (modified model) between the seed and powder was established, which could effectively characterize the effect of the water addition on the viscosity. The seed pelletizing numerical simulation test was carried out with the average number of contact particles as the main evaluation index. The results showed that the amount of powder adhering to the surface of individual seeds was 43. Bench test results show that the quality of pelletized seeds met relevant criteria. KeywordsDiscrete element method (DEM)Numerical simulationSeed pelletizingContact modelRepose angle

Thermal fatigue life prediction of brake disks based on coupled thermal simulation

The thermal-mechanical performance of friction pairs of the foundation brake gear is an important guarantee for the safe operation of high-speed trains. The thermal stress of brake disks under high temperature is the primary cause of thermal fatigue damage. In this article, the brake bench tests were carried out under braking speed of 350km/h and a thermo-mechanical-wear coupled model was established to simulate tests. By analyzing the results of bench test and finite element simulation, it shows the top temperature of brake disk was over 600°Cand the friction surfaces of brake friction pair show obvious wear. Combining the FE simulation and test results of the thermal fatigue sample, the thermal fatigue characteristics of brake disk material were studied. Based on the residual stress results, the propagation life of brake disk thermal fatigue crack was estimated. It shows that when the crack length increases to 10mm, the crack propagation life of brake disk is halved, and continues to decrease as the crack grows.

Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized 13C and Deuterium 2H Metabolic MRS Imaging at Ultrahigh Fields.

Information on the metabolism of tissues in healthy and diseased states plays a significant role in the detection and understanding of tumors, neurodegenerative diseases, diabetes, and other metabolic disorders. Hyperpolarized carbon-13 magnetic resonance imaging (13C-HPMRI) and deuterium metabolic imaging (2H-DMI) are two emerging X-nuclei used as practical imaging tools to investigate tissue metabolism. However due to their low gyromagnetic ratios (ɣ13C = 10.7 MHz/T; ɣ2H = 6.5 MHz/T) and natural abundance, such method required a sophisticated dual-tuned radiofrequency (RF) coil. Here, we report a dual-tuned coaxial transmission line (CTL) RF coil agile for metabolite information operating at 7T with independent tuning capability. The design analysis has demonstrated how both resonant frequencies can be individually controlled by simply varying the constituent of the design parameters. Numerical results have demonstrated a broadband tuning range capability, covering most of the X-nucleus signal, especially the 13C and 2H spectra at 7T. Furthermore, in order to validate the feasibility of the proposed design, both dual-tuned 1H/13C and 1H/2H CTLs RF coils are fabricated using a semi-flexible RG-405 .086" coaxial cable and bench test results (scattering parameters and magnetic field efficiency/distribution) are successfully obtained. The proposed dual-tuned RF coils reveal highly effective magnetic field obtained from both proton and heteronuclear signal which is crucial for accurate and detailed imaging. The successful development of this new dual-tuned RF coil technique would provide a tangible and efficient tool for ultrahigh field metabolic MR imaging.

Scale up validation tests for Buckingham Pi theorem applied to leaf test experiments for iron ore slurry

Bench tests were conducted on ore slurry filtration using the leaf test method, varying scales, pressures, and water/solids ratios. These results were compared with analytical outcomes derived from applying the dimensionless Buckingham pi method to the general equation of slurry filtration with incompressible cakes under constant pressure. The aim was to validate the tests by corroborating experimental findings with calculated parameters for scale-up purposes. Vacuum pressure was employed to facilitate slurry dewatering, forming a cake comprising solids from the slurry. This cake’s thickness evolved over time, introducing specific resistivity that impeded filtering efficiency. Parameters such as cake resistance and filter media resistance were computed. Filtrate volume was measured over time to determine the filtration rate. These values were then adjusted using factors obtained through dimensional analysis. These factors facilitated comparisons to validate the feasibility of employing the Buckingham pi method for predicting slurry filtration results at larger scales. The results indicated lower errors when analyzing the filtrate rate over time with a solids/water ratio of 20/80%. When evaluating cake resistance, the method yielded lower errors at a ratio of 70/30%, while results for medium resistance were inconclusive. It’s important to consider the ratio and associated errors when predicting the behavior of an industrial filter based on bench test results, aiming to achieve theoretical scaled filtration rates and cake resistances. However, it’s not advisable to rely on the Buckingham pi method for scale-up purposes when evaluating medium resistance.

A temporal discretization and spatial integration SCR model with dual temperature-related parameters

Developing an accurate and rapid Selective Catalytic Reduction (SCR) model is crucial for advanced control strategies, which is challenging due to the complex physicochemical processes. In this paper, a novel control-oriented SCR model is proposed, which exhibits faster and more accurate estimation performance for both NOx and NH3 emissions. Unlike traditional modeling methods, this research develops a temporal discretization and spatial integration (TDSI) SCR model with dual temperature-related parameters. By introducing NH3 recycling, the spatial integration model is improved, leading to an enhanced accuracy in model estimation. Moreover, A time discretization method based on current state can effectively address the issue of sampling time sensitivity. Additionally, dual temperature-related parameters can significantly enhance model accuracy, particularly in high-temperature regions. A simplified and clear flowchart is provided for parameter identification based on a limited number of engine bench test results. In a cold-start World Harmonized Transient Cycle (WHTC), the TDSI model can achieve NOx and NH3 accuracies of 92.26% and 92.52%, respectively, with a computation time of 1.47 s. Through comprehensive comparisons, the proposed model exhibits comparable accuracy to the GT model while significantly reducing computation time by 98.39%. Additionally, compared to the Continuous Stirred-Tank Reactor (CSTR) and θT models, there is an approximate 3% improvement in NOx and NH3 accuracies. This TDSI model provides a foundation for designing urea injection control strategies and offers new perspectives for simplifying the model design.

Influence and optimization of swirler parameters on elbow wear of deep coal fluidization pipeline transportation system

Elbow wear is a major threat to the multiphase pipeline transportation industry, which has a negative impact on the stable operation of the transportation system. In order to find the wear reduction methods of elbows in the fluidization pipeline transportation system for 2000-meter-deep coal resources, the swirler was installed upstream of the elbows, and wear simulations and tests of three kinds of elbows were carried out. The results showed that the maximum wear rate (MWR) of elbows increased and then decreased along the elbow angle. Due to the different directions of gravity, the heavy wear position (HWP) of the horizontal-vertical (H-V) elbow was in front of the vertical-horizontal (V-H) elbow. Because the downstream portion of the horizontal-horizontal (H-H) elbow was still a horizontal pipe, the HWP of the H-H elbow almost covered the whole elbow. The swirler placed upstream of the elbows could make the particles at the elbow move to the intrados of the elbows, resulting in less collision between the particles and the extrados of the elbows, thus reducing the wear of the elbows. The wear reduction effects of swirlers on three different elbows were favorably connected with the guide vane angle (GVA) and negatively correlated with the guide vane length (GVL), decreased first and then increased as the guide vane height (GVH) increased, and were little affected by the guide vane number (GVN) and the guide vane thickness (GVT). The mathematical models between the MWR of the elbows and guide vane parameters were established. By bench tests, the wear reduction effect of three kinds of elbows under the optimal guide vane parameters was 58.4%, 76.9%, and 78.6%, respectively. The errors between the bench test results and the simulation results were around 10%.

Design of the electron cyclotron emission diagnostic on EXL-50 spherical torus

The electron cyclotron emission (ECE) diagnostic system has been developed on the ENN spherical torus (EXL-50). The ECE system is designed to detect radiation emitted by energetic electrons, rather than conventional 1D electron temperature profile measurement, in the frequency range of 4−40 GHz. The system is composed of five subsystems, each covering a different frequency band, including the C-band (4−8 GHz), X-band (8−12 GHz), Ku-band (12−18 GHz), K-band (18−26.5 GHz) and K -band (26.4−40 GHz). The system uses heterodyne detection to analyze the received signals. The K-band and K -band subsystems are located horizontally in the equatorial plane of the EXL-50, while the C-band, X-band and Ku-band subsystems are located under the vacuum vessel of the EXL-50. To direct the microwaves from the plasma to the antennas for the horizontal detection subsystems, a quasi-optical system has been developed. For the vertical detection subsystems, the antennas are directly attached to the port located beneath the torus at = 700 mm, which is also the magnetic axis of the torus. The system integration, bench testing and initial experimental results will be thoroughly discussed, providing a comprehensive understanding of the ECE system’s performance and capabilities.