Latest ArticlesThe rapid development of new energy vehicles has made the industry’s requirements for high-performance automotive motors continue to increase. Hybrid excitation motor is a new type of motor. The hybrid excitation motor combines the advantages of permanent magnet excitation and electric excitation, and has excellent regulation and reliability. A parallel claw-pole hybrid excitation motor structure was proposed. The magnetic circuit of the hybrid excitation motor was optimized by means of parallel axial excitation of permanent magnet and electric excitation device. On this basis, the parametric simulation of the thickness of the claw pole side plate and the large end of the excitation bracket of the motor was carried out respectively, and the average torque of the motor before and after optimization was simulated according to the optimal structure. Finally, the mechanical characteristic curves of the parallel claw-pole hybrid excitation motor and the permanent magnet synchronous motor were compared and analyzed. The results show that the parallel claw-pole hybrid excitation motor broadens the operating range of the motor by 17.24% on the basis of maintaining the torque performance, and improves the mechanical properties and adaptability of the hybrid excitation motor.
Aiming at the problem of high water content and low degree of recovery of low permeability heavy oil reservoir in Guan128 block of Dagang Oilfield, the microscopic seepage law and residual oil characteristics of viscosity reducers flooding were studied through indoor experiments, and the planar wave and characteristics and residual oil distribution law were quantitatively analysed with the help of AI intelligent recognition. The experimental results show that after the viscosity reducer emulsification of crude oil, the emulsion aggregates and can block the water-driven flux channels, the advantageous transport channels of oil droplets increase, improve the wave and reach coefficient, and reduce the oil saturation. AI image identified pore throat droplets of oil, the wall membrane oil, the residual oil in the dead corner and the residual oil without wave and flake oil and other types of residual oil distribution, and the formation mechanism was analyzed, and measures of surfactants injection and encryption of the network of wells were put forward, and the blocking of high seepage channels was adjusted. Adding viscosity-reducing agent system can reduce the starting pressure gradient and improve the fluidity of heavy oil. After the conversion of water drive to chemical drive, the oil washing effect of residual oil in the pores and throat and residual oil in the dead space is improved, and the recovery rate is increased by 15.28%. The research results provide important theoretical reference for the research on the mechanism of efficient oil enhancement and field application of viscosity-reducing agent injection in the late stage of water-drive development of low-permeability heavy oil reservoirs.
For the problems of low efficiency and long computational time in the fluid-structure interaction of free-surface flow and elastic structure, an efficient fluid-structure coupling method for free surface flow was developed by combining the volume of fluid method with the fast dynamic mesh method based on the structure-pseudo elastomer. The free surface of the fluid was tracked by volume of fluid (VOF) method. The fluid domain was regarded as a pseudo elastomer, then the structure-pseudo elastomer system was constructed. The multiphase fluid force at the fluid-solid interface was used as the excitation to solve the dynamical equations of the system to obtain the structural vibration displacements and the mesh deformations of the flow field. The fluid flow, structural deformation and the dynamic mesh were solved sequentially at each time step to solve the fluid-structure interaction problem. Based on the developed method, the fluid-structure coupling response of elastic baffle under the impact of dam-breaking flow was calculated. The motion behaviors of the free liquid surface of water and elastic baffle were obtained. The results show that the free liquid surface evolution and elastic baffle vibrational displacements are well in agreement with those of the existing algorithm, under the same mesh size, the method can reduce the computational time by 33.3% compared with the existing algorithms, under the impact of water flow, the elastic baffle is bent slightly to the impact side. Then the water rises along the left side of the baffle and forms a jet, and the baffle is bent greatly to another side. Finally, the amplitude of the baffle gradually decreases due to the damping of the fluid on both sides.
The shale of Middle-Upper Permian in the Lower Yangtze area is an important source rock in the region, but the research on the elemental characteristics of different sedimentary facies is still lacking in the past. Continuous X-ray fluorescence(XRF) element scanning was performed on the shale core of the Middle-Upper Permian in Well Gangdi 1 in the Lower Yangtze Region. The contents of main elements such as Si, Al, Ca, Fe and trace elements such as Sr, Rb, Ti and their ratios in the middle and upper Permian strata were analyzed, and the evolution characteristics of sedimentary environment were discussed in combination with the quantitative analysis of mineral composition of samples. The results show that the elements such as Al, Ti, Si and Rb, which have strong indicative significance for terrestrial deposition, have a high-high-low variation in the vertical direction. The Ca, Sr and other elements indicating marine deposits are mainly concentrated in the upper Dalong Formation, and the content of other layers is low, and there are abnormal values in some areas. The ratio of element content has a certain rule, among which Rb/Sr and Ba/Sr show a low-high-low trend. The maximum value of Al/(Al+Fe+Mn) ratio is 0.8, the minimum value is 0.4, and the average value is 0.71, which is generally greater than 0.6, indicating an important source of biogenesis. The Middle-Upper Permian belongs to the transitional-marine reduction environment. From bottom to top, the sedimentary environment changes from deep-water basin facies to deep-water shelf facies to sea-land transition facies to shallow-water shelf facies. During this period, the water body changes from deep-shallow-deep. Among them, the early stage of the Gufeng Formation is the deep-water basin phase, and then gradually enters the deep-water shelf phase. The Longtan Formation is dominated by the sea-land transition phase, and the relative sea level changes frequently during the sedimentary period. In the deep-water period, the lithology is dominated by self-deposited limestone, and the corresponding element Ca content is high. In the shallow water period, it is mainly light gray mud shale deposition, and the corresponding main elements change to Si and Al. After the short-term subsidence of the sea level in the Dalong Formation, the water body gradually deepened, dominated by continental shelf deposition.
In order to effectively reduce the erosion and wear rate of ordinary elbows and extend their service life. A stomach-type elbow was proposed, based on the theory of gas-solid two-phase flow, the Fluent software was used on the stomach-type elbow to numerically simulate and analyze fluid erosion characteristics. The analysis results show that the second circular cross-section position less than 7.5°, greater than 25.0° less than 40.0° of the gastric bend has an erosion-resistant effect, in which the second circular cross-section position of 35.0° of the gastric bend erosion-resistant effect is the best, compared with the ordinary elbow erosion-resistant performance increase by 9.88%. The flow rate increases from 8 m/s to 28 m/s, and the maximum erosion rate of the gastric bend and ordinary elbow at 35.0°, 37.5°, 30.0° and 32.5° increases by 26.08 times on average. The particle diameter increases from 45 mm to 120 mm, and the maximum erosion rate increases by 1.71 times. The mass flow rate increases from 0.02 kg/s to 0.12 kg/s, and the maximum erosion rate increases by 7.35 times. Mass flow rate increases from 0.02 kg/s to 0.12 kg/s, the maximum erosion rate increases by 7.35 times. Regardless of the flow rate, particle diameter, mass flow rate, 35.0°, 37.5°, 30.0°, 32.5° of the maximum erosion rate of the gastric bend is always less than the maximum erosion rate of the ordinary elbow, that is, all have the effect of anti-erosion, of which 35.0° of the gastric bend on the whole has the best anti-erosion effect. The elbow can effectively reduce the rate of erosion and wear to extend the service life of the pipeline, but also for the elbow of the anti-erosion structure design and optimization to provide a new design scheme.
Fan nozzle is an important part of high pressure water descaling system, and its internal structure parameters directly affect the performance of jet. The nozzle flow field was analyzed by using fluid simulation software FLUENT, and the nozzle exit diameter, cone section contraction angle and exit contraction angle were selected as reference factors. The jet impact force was used as evaluation index, and the nozzle structure parameters were optimized by response surface method. The results show that the velocity distribution of the internal flow field is affected by the single factor of the diameter of the outlet section and the conical contraction angle, but the flow rate of the nozzle is little affected. The pressure drop of nozzle is affected by the change of the diameter of outlet section and the contraction angle of nozzle outlet, and the influence of the contraction angle of nozzle conical section on the pressure drop is negligible. When the diameter of the outlet section is 3.15 mm, the taper shrinking angle is 26.17°, and the outlet shrinking angle is 40.93°, it is found that the nozzle striking force is increased from the original 94.91 N to the optimized 143 N by establishing the outflow field and applying the gas-liquid two-phase flow model simulation calculation. The research results provide theoretical guidance for optimizing nozzle structure to enhance jet impact force.
Quality distribution detection is regarded as a crucial basis for regulating the rare earth extraction process. The variation of the lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd) solution system during the saponified P507-kerosene extraction is significant, showing obvious nonlinear characteristics such as time-varying and strong coupling. Moreover, the solution system exhibits no apparent color change. Existing soft measurement methods based on machine vision and artificial neural networks have shown unsatisfactory application effects. To address these issues, a mechanistic modeling method was first employed to construct a mathematical model for the quantitative analysis of the four components. Subsequently, by measuring the characteristic gamma-ray intensity information of the natural radioactive isotope 138La@1.436 MeV (auxiliary variable), the mass distribution information of the four components (main variable) was predicted simultaneously. Finally, experiments were conducted based on a high-purity germanium detector. The results show that the minimum detectable mass concentration of La is 1.70 g/L. Compared with the experimental results, the relative errors of the predicted mass concentrations of La, Ce, Pr, and Nd are -3.11%~4.23%, -5.81%~3.74%, -8.16%~6.68%, and -19.87%~14.20%, respectively. The relative errors of the sensitivity prediction are 1.33%, 5.56%, -3.20%, and -0.41%, respectively. The proposed “gamma ray-soft measurement” method enables high-accuracy and high-sensitivity prediction of the four components La, Ce, Pr, and Nd. The detection process is not affected by changes in extraction system density, acidity, temperature, and other parameters, providing new technical references for rare earth extraction quality distribution detection.
To solve the problem of insufficient extraction of sport features by dual stream networks in current action recognition, which leads to low recognition accuracy, a action recognition method based on sport feature enhancement two-stream networks was proposed to improve accuracy. The network was divided into spatial stream and temporal stream, with the same structure but different inputs. The input of the spatial stream network was a video frame sequence, while the input of the temporal stream network was a video frame difference sequence. The network structure used Resnet50 as the backbone network, replacing the 3×3 convolution with the proposed global sport feature module and local sport feature module, fully extracting video sport information, and finally combining spatial and temporal stream to output the results. The results show that the accuracy of the model on the UCF101 and HMDB51 datasets reaches 96.8% and 75.3%, which is superior to traditional algorithms.
Accurately identifying the connecting handle of the train coupler is of great significance for the operation of the uncoupling robot. A train connection handle target recognition algorithm based on improved YOLOv5 was proposed to address this issue. The C_switchable atrous convolution(C_SAC) module was integrated into the backbone feature extraction network, and the wise intersection over union(WIOU) function was introduced as a new bounding box loss function to enhance the feature extraction ability of the backbone network, improve the model’s generalization ability and convergence rate. Then, images of the connecting handles of train couplers in different environments and positions on the production site were collected for recognition. The experimental results show that the improved YOLOv5 algorithm achieves a target recognition rate of 96.6% for the connecting handles of train couplers. Compared with the original algorithm, it shows significant improvements in accuracy, recall, average accuracy, and other aspects. Finally, it was applied in the development of an automatic uncoupling robot for train carriages, greatly improving the accuracy and effectiveness of automatic uncoupling.
In order to mitigate the impact of wind power fluctuations on the power grid, a hybrid energy storage system (HESS) control strategy was proposed, which optimized the parameters of variational mode decomposition (VMD) using the mayfly algorithm (MA). Firstly, the sliding average algorithm was employed to determine the wind power grid connected power that met the grid standards. Then, a fitness function was constructed by combining two evaluation criteria, and the optimal parameters of the VMD algorithm were determined using the mayfly algorithm. The optimal parameters were then introduced into the VMD algorithm to decompose the hybrid energy storage power, realizing the initial allocation of the hybrid energy storage power. Finally, fuzzy control was utilized to optimize the state of charge (SOC) of the energy storage devices, adjusting the power commands of supercapacitors and lithium batteries. The results indicate that the proposed strategy not only enables adaptive decomposition and rational allocation of hybrid energy storage power, effectively mitigating wind power fluctuations but also ensures the SOC of the energy storage devices remains within a reasonable range, achieving safe and stable operation of the HESS.