Results Of Simulation Research Research Articles

SIMULATION OF TORQUE VARIATIONS IN A DIESEL ENGINE FOR LIGHT HELICOPTERS USING PI CONTROL ALGORITHMS

This article presents the results of simulation research of a diesel engine for a light helicopter. The simulations were performed using the 1D software AVL Boost RT. The engine model includes elements such as cylinders, turbine, compressor, inlet and outlet valves, ambient environment definition, and fuel injection control strategy. The simulations aimed to evaluate the engine's response to step changes in the main rotor load, both increasing and decreasing power demands. Parameters analyzed included power deviation, torque, engine rotational speed, and stabilization time of the main rotor rotational speed. All tests were conducted using a single set of PI controller settings. The results demonstrate that these parameters are dependent on the magnitude of the step change in the main rotor load demand. The study compares the maximum engine rotational speed deviation from the nominal value for both increasing and decreasing main rotor load demands. The findings indicate that using PI regulator to control rotational speed in the diesel engine in a light helicopter significantly depends on the change in the load torque on the rotor.

Research on Photovoltaic Power Generation Characteristics of Small Ocean Observation Unmanned Surface Vehicles

Under the action of waves, a small unmanned surface vehicle (USV) will experience continuous oscillation, significantly impacting its photovoltaic power generation system. This paper proposes a USV photovoltaic power generation simulation model, and the efficiency of photovoltaic MPPT control under wave action is studied. A simulation model for solar irradiance on solar panels of USV under wave action is established based on CFD and solar irradiation models. The dynamic changes in irradiance of USV solar panels under typical wave conditions are analyzed. The MPPT efficiency of USV photovoltaic power generation devices under continuously changing irradiance conditions is studied on this basis. The simulation research results indicate that waves and solar altitude angles significantly impact the instantaneous irradiation energy of USV photovoltaic devices. However, the impact of waves on the average irradiance is relatively tiny. The sustained oscillation of irradiance poses certain requirements for the Maximum Power Point Tracking (MPPT) control frequency of USV photovoltaic systems; a disturbance control frequency of no less than 50 Hz is proposed.

Effect of burner structural parameters on combustion characteristics and NOx emission of natural gas

The low-nitrogen combustion of natural gas has always been a crucial topic in environmental protection. Currently, small and medium-sized industries use straight-through pipelines as their burner nozzles. This design results in poor heat diffusion capacity after mixed combustion and a long time of temperature diffusion, leading to low combustion efficiency and high NOx emissions. To address this issue, a new type of natural gas low-nitrogen burner with a multi-port diffusion nozzle was developed. The burner’s structure was optimized through a combined approach of experiment and numerical simulation. The optimal structural parameters for the burner are a 40° swirl angle and 8 swirl blades, as indicated by the numerical simulation research results. The designed multi-port diffusion nozzle is matched with the appropriate swirl angle and number of blades to promote natural gas diffusion, forming an annular space region flames and a stable flame shape with a height of 0.64 m. After optimization, the average concentration of NOx at the outlet of the combustion chamber decreased from 61.5 ppm to 20.81 ppm. A natural gas low-nitrogen combustion experimental system was designed and constructed based on simulation results. The experimental results were analyzed in terms of flame structure characteristics, temperature distribution, and NOx emissions. The results indicate that the trend in temperature change is consistent with the simulation process. The NOx concentration at the outlet of the combustion chamber was measured by the flue gas analyzer to be 34.1 ppm, which was 5.3 ppm lower than the NOx concentration calculated by numerical simulation. The new burner exhibited better flame stability and a 12.6 % reduction in NOx emissions compared with a traditional straight-through pipeline burner of the same size. The designed natural gas low-nitrogen burner appears to be a suitable device for reducing NOx emissions in small and medium-sized industries.

A review on hazards and risks to pipeline operation under transporting hydrogen energy and hydrogen-mixed natural gas

As an efficient and clean fuel, hydrogen energy plays an important role in relieving the energy crisis and achieving the orientation of zero carbon emissions. Transportation is the key link in the construction of hydrogen energy infrastructure. For large-scale and long-distance transportation of hydrogen, pipeline transportation has the advantages of high efficiency and cost saving. While using the existing natural gas pipeline to transport hydrogen, it would economize the economic cost, time cost and labor cost. However, the transportation of hydrogen may bring more hazards and risks. Based on the investigation of a large number of literatures, the research advance in hydrogen embrittlement, leakage, combustion and explosion risk of hydrogen and hydrogen-mixed natural gas pipelines was reviewed. The mechanism, research means and evaluation methods of hydrogen embrittlement, as well as the experimental and numerical simulation research results of leakage, combustion and explosion were discussed in detail. The definite and important conclusions include: (1) For buried hydrogen-mixed natural gas transportation pipeline, the leakage rate of hydrogen and methane is the same, the formation of the leakage crater is foreign to the nature of leakage gas. (2) When adding less than 25 volume percentage of hydrogen into the natural gas pipelines, the explosion risk would not be increased. Future research should focus on the risk prediction, quantitative risk assessment, intelligent monitoring, and explosion-suppression technical measures of hydrogen and hydrogen-mixed natural gas transportation pipelines, so as to establish comprehensive and multi-level pipeline safety protection barriers.

English

This paper presents the research and construction of a motion tracing control system for omnidirectional mobile robots based on reinforcement learning techniques in automatic control. The process of controlling a mobile robot in a flat environment with definite and unknown obstacles, taking into account the nonlinear factor of interference. Research and application of programming tools are operating systems for mobile robots (Robot Operating System - ROS). From updated information on maps, operating environment, robot control position, and obstacle identification (SLAM) to calculate the movement trajectory of a three-wheeled omnidirectional mobile robot. The positioning system calculates the orbital tracking for the robot based on the Q-learning algorithm. The results of simulation research in the Gazebo environment and running tests on real Turtlebot mobile robots have shown the practical effectiveness of the research problem of tracking motion tracking and intelligent navigation for mobile robots.

Recovering and accumulating energy in regenerative braking of a garbage truck using hydro-mechanic power split transmission

Hydro-mechanical power-split transmissions (HPSTs) are a kind of continuously variable transmission; HPSTs integrated with the hydraulic energy recovery and accumulation function are the most coherent selection to im-prove the energy efficiency of the garbage truck. With an accumulator located in the speed-increasing hydraulic converter of the HPSTs, it is possible to recover and accumulate energy during braking and reuse energy when starting, accelerating or using other technologies in the process of garbage collection and transportation. Some results of simulation research and analysis of the energy recovery and accumulation process introduced in this paper can be used as a scientific basis for the complete design of energy saving powertrain systems, quality, and environmental friendliness for garbage trucks. In this study, the results of the simulation and analysis of the energy recovery and accumulation process were reported. Our findings can be used as a scientific basis for the complete design of energy saving powertrain systems, quality, and environmental friendliness for garbage trucks.

Effects of Magnetic Fields in Arc Welding, Laser Welding, and Resistance Spot Welding: A Review

The application of magnetic field in welding process has been proved to be effective in improving the mechanical properties of welded joints and is regarded as a practicable auxiliary welding method. Although the theoretical research on magnetic field‐assisted welding is quite abundant, there is still a long way to go before a stable industrial application is achieved. Therefore, to clarify magnetic field and compare its roles in various welding techniques, this work carefully examines the use of magnetic field in recent welding techniques such as laser welding, laser‐melt inert gas hybrid welding, gas metal arc welding, tungsten inert gas welding, and resistance spot welding. Based on previous experiments and simulation research results, the effects of the Lorentz force on the arc, molten pool, and dendrite solidification during welding as well as the microstructure and mechanical properties of welded joints are discussed. The purpose of this work is to give a superficial introduction to the magnetic field‐assisted welding method in recent years, hoping to improve the welding practitioners’ understanding of the magnetic‐assisted welding method and provide a reference for researchers who use different welding methods.

The Construction of College Sports Culture Based on Intelligent Information Management Technology

In order to improve the effect of sports culture construction in colleges and universities, this study combines intelligent information management technology to analyze the path of sports culture construction in colleges and universities and builds an intelligent system to assist the construction of sports culture in colleges and universities. Moreover, this study describes the oversampling SMOTE algorithm for imbalanced datasets, proposes specific problems that need to be solved to optimize the SMOTE algorithm, and provides a unified classification model for the classification of imbalanced datasets. In addition, this study constructs a college sports culture construction platform based on intelligent information management technology. According to the simulation research results, it can be seen that the college sports culture construction platform based on intelligent information management technology proposed in this study has a good sports culture construction effect.

Investigation of Changes in Fatigue Damage Caused by Mean Load under Block Loading Conditions.

The literature in the area of material fatigue indicates that the fatigue properties may change with the number of cycles. Researchers recommend taking this into account in fatigue life calculation algorithms. The results of simulation research presented in this paper relate to an algorithm for estimating the fatigue life of specimens subjected to block loading with a nonzero mean value. The problem of block loads using a novel calculation model is presented in this paper. The model takes into account the change in stress–strain curve parameters caused by mean strain. Simulation tests were performed for generated triangular waveforms of strains, where load blocks with changed mean strain values were applied. During the analysis, the degree of fatigue damage was compared. The results of calculations obtained for standard values of stress–strain parameters (for symmetric loads) and those determined, taking into account changes in the curve parameters, are compared and presented in this paper. It is shown that by neglecting the effect of the mean strain value on the K′ and n′ parameters and by considering only the parameters of the cyclic deformation curve for εm = 0 (symmetric loads), the ratio of the total degree of fatigue damage varies from 10% for εa = 0.2% to 3.5% for εa = 0.6%. The largest differences in the calculation for ratios of the partial degrees of fatigue damage were observed in relation to the reference case for the sequence of block n3, where εm = 0.4%. The simulation results show that higher mean strains change the properties of the material, and in such cases, it is necessary to take into account the influence of the mean value on the material response under block loads.

Utilization of Cable Screen Earthing Current for Detection and Location of Earth Faults in Medium Voltage Networks

The paper presents issues related with detection and location of earth faults in medium voltage (MV) networks. Attention is paid on cable and cable-overhead lines. The criterion value – cable screen earthing current is presented. Afterwards, the method of utilization of the cable screen earthing current for detection and location of earth faults is described. The next part of the paper presents the results of simulation research for different variants of earth faults in cable and cable-overhead lines. The presented relations are the basis of the developed algorithm of detection and localization of earth faults. The presented considerations were confirmed by an experiment performed in the MV network.

The use of the gas flow model to improve the design of the piston-rings-cylinder system of a diesel engine

The article presents the results of simulation research aimed at assessing the impact of selected dimensions of the rings and piston on the ring-pack operation and developing proposals of changes that will improve its performance. The object of the research was a diesel engine for delivery vehicles. A mathematical model of the ring-pack developed by the author of this work was used for the research. The results have shown that with restrictions imposed by the engine manufacturer regarding the scope of modernization, it is possible to significantly reduce or even eliminate the reverse gas flow from the inter-ring space to the combustion chamber, but this must be done at the expense of increased blow-by. The effect of proposed changes on the axial displacement of the rings in the grooves has also been discussed.

Technological Innovation in the Aspect of Safety in the Process of Heat Supply

Abstract In recent years heating in Poland has been transformed as a result of the priorities of the country's energy policy implemented within the European Union. The increase in energy security, the development of renewable energy sources and the fulfilment of legal and environmental requirements are very important. Exploitation of district heating systems should ensure reliable and safe heat supplies for industrial and municipal customers with high energy efficiency and reduction of environmental impact. The article discusses the conditions and directions of centralized heating systems development as well as technical and economic issues, which are important for the security of heat supply. The Author describes selected technological innovations used in the technical infrastructure for heat transfer and modern IT systems which are improving the management of heating systems. The article includes the results of simulation research with use of IT tools showing the impact of selected innovations on the improvement of network operation conditions. Directions of modernization of heating systems in the aspect of increasing energy efficiency and security of heat supply have also been indicted here.

The method of optimal route selection in road transport of dangerous goods

Abstract Dangerous goods such as: liquid fuels, chlorine, ammonia, gases, corrosives, radioactive material, toxic and other substances are being transported by road in Poland on a daily basis. ‘Dangerous goods’ are materials or items with hazardous properties which, if not properly controlled, present a potential hazard to human health and safety, infrastructure and or their means of transport. However, from year to year a systematic growth of accidents of the substances mentioned has been observed. It is estimated that several hundred traffic collisions, involving vehicles carrying hazardous goods, are being registered. Those accidents lead to spills penetrating into the soil, groundwater and watercourses, causing degradation of biological life. Therefore, the question of safety is an important problem that must be faced by senders, recipients and transport companies. One way of improving safety conditions is risk assessment. Therefore, in the article present the method of selection model of road transportation of dangerous goods. The model generates routes that are optimal from the perspective of risk and losses minimization. In addition, the paper adopts the results of simulation research selected delivery routes in Poland, with the use of the Breadth First Search algorithm (BFS) and proprietary application called the Safest Path Finder.

Structure and Performance of Polygonal Electrode Linear Ion Trap

Abstract The polygonal electrode linear ion trap (PeLIT) can produce quadrupolar electric field plus some higher order field, which balances the relationship between mass resolution and electrode manufacturing difficulties. The electrodes of PeLIT are relatively simple, but have a good mass resolving power. This study investigated the relationship between the electric field distribution and the ion trap structures, and the performances of PeLIT through theoretical simulation and experimental study. Research results of simulation showed that the polygonal electrode linear ion traps with different structures had different electric field distributions and mass analysis performances. The negative decapole field distorted the performances significantly. The experimental results showed that the mass resolution of reserpine ions (m/z 609) was more than 2500 using a polygonal electrode ion trap. At the same time, mass selective excitation and tandem mass spectrometry experiments were also carried.

Neural State Estimator for Complex Mechanical Part of Electrical Drive: Neural Network Size and Performance of State Estimation

Abstract This paper presents the results of simulation research of an off-line-trained, feedforward neural-network-based state estimator. The investigated system is the mechanical part of an electrical drive characterised by elastic coupling with a working machine, modelled as a dual-mass system. The aim of the research was to find a set of neural network structures giving useful and repeatable results of the estimation. The mechanical resonance frequency of the system has been adopted at the level of 9.3-10.3 Hz. The selected state variables of the mechanical system are load, speed and stiffness torque of the shaft.

Generalized logistic functions in modelling emergence of Brassica napus L.

The objective of this study was to determine whether generalized logistic functions (Richards model with time shift) may be used to predict emergence of winter rapeseed (Brassica napus L.) after its seed treatment with plant extracts from Taraxacum officinale roots under controlled environment conditions. Emergence analyses were conducted for winter rape whose seeds were treated with a plant extract and for the non-treated seeds sown to the soil at the site of earlier point application of the extract. Curves were plotted for experimental data by minimizing the square sum of differences between the experimental data and the mathematical model. To evaluate model fit, the mean squared error was divided into four factors. Computing modelling efficiency coefficients were also introduced to enable complete analysis. Results of simulation research demonstrate that the determined parameters of curves (e.g. values of growth parameters, time shift or the upper limit of population) describing the number of seedlings in the function of time stayed compliant to the interpretation with regard to the biology of the analyzed processes. The proposed mathematical description based on generalized logistic functions showed extraordinary fit (r = 0.999) to the experimental data, which makes it highly useful in predictive control of rapeseed emergence. In addition, the study enabled concluding that plant extracts application to the soil allowed achieving a higher maximal emergence rate compared to the control sample. The application of the plant extracts increased the final population of rapeseed and significantly accelerated the occurrence of the maximal emergence rate.

Model numeryczny mieszalnika fazy ciekłej

Presented is the course of conduct during modeling of phenomena occurring in a mixer intended for mixing liquids. Issues related to the numerical description of phenomena occurring in this type of constructions are discussed, the method of modeling the mixing process for one type of liquid by the analysis of several types of mixing arms is presented and the results of simulation research are discussed.

A wastewater retention canal as a sewage network and accumulation reservoir

The paper presents an innovative retention canal for storm sewage as a competitive solution in relation to the ones currently used. The principle of operation of the retention canal, the conditions of its use in a sewage network and the basis for dimensioning were presented. To demonstrate its versatility and retention efficiency, comparative studies on the example of a drained catchment were carried out. A linear network layout composed of 12 storm canals with the retention reservoir located at the network outlet was assumed. Based on the developed algorithm, simulation tests were performed with the use of the SWMM 5.1 program. On the basis of hydrodynamic modelling it was determined: (1) the required geometry of storm canals, (2) the geometry of damming partitions and (3) the process of wastewater accumulation in the retention canal. Having the results of simulation research for rainfalls with a duration of 10 to 100 minutes, the critical rainfalls for network and retention canal dimensioning were determined. The comparison of hydrographs of sewage outflow from the examined catchment is interesting. From the value of 3.62 m3/s in the network it decreases three times to just 1.16 m3/s at the outlet of the retention canal. The retention canal with diameters identical to those established for the network, allow achieving the sewage retention capacity, which corresponds to a capacity of 1,844 m3 for a multi-chamber retention reservoir. Thus, the retention canal fully replaces the operation of a network of certain geometry and retention reservoir. The results of the research allowed the formulation of a number of important conclusions, including conclusions on cognitive significance. The critical rainfall appointed for the design of the retention canal always lasts longer than that, determined for the sewage network design. The retention canal is suitable for widespread use in the canals of new and already existing storm sewage systems and combined sewage systems.*

Searching for optimal machine learning algorithm for network traffic classification in intrusion detection system

The main problem associated with the development of an effective network behaviour anomaly detection-based IDS model is the selection of the optimal network traffic classification method. This article presents the results of simulation research on the effectiveness of the use of machine learning algorithms in the network attacks detection. The research part of the work concerned finding the optimal method of network packets classification possible to implement in the intrusion detection system’s attack detection module. During the research, the performance of three machine learning algorithms (Artificial Neural Network, Support Vector Machine and Naïve Bayes Classifier) has been compared using a dataset from the KDD Cup competition. Attention was also paid to the relationship between the values of algorithm parameters and their effectiveness. The work also contains an short analysis of the state of cybersecurity in Poland.

Modelling of Beetroot Seedlings with Modified Generalized Logistic Functions

Abstract Modified generalized logistic functions (also known as Koya-Goshu functions) were used for mathematical description of germination. These functions constitute natural modification of traditionally used Richards' function for description of plants germination that introduces a non-linear time increase in exponent and an element related to time shift. Curves were adjusted to experimental data based on minimization of the square sum of difference between experimental data and a mathematical model (the smallest squares method). Results of simulation research show that the determined parameters of curves (e.g., values of the growth parameter, time shift or upper limit of population) describing the number of seedlings as a time function stay compliant to interpretation with regard to biology of the investigated processes. Based on the research, it was stated that for control and application of plant extracts to soil, Koyu-Gosha model has better adjustment to experimental data in comparison to the generalized logistic model.