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- Performance Study of Concrete Beam-Column Joints in Building Steel
Structures Under High-Intensity Vibration
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Authors: G Li, Y Fan, N Du
Pages: 107 - 117
Abstract: In order to minimize the loss of life and property in an earthquake, the beam-column joints of buildings need to have good seismic performance. This paper briefly introduced concrete beam-column joints and used a steel skeleton to strengthen the seismic performance of concrete beam-column joints. The concrete beam-column and reinforced concrete beam-column joints were prepared for experimental analysis. The skeleton curve and energy dissipation capacity of the joints were tested using quasi-static loading experiments. The relative displacement of the column at different heights in the beam-column joints was tested under an eight-degree earthquake simulated by a vibration table. The results showed that the reinforced concrete beam-column joint had higher peak loads and ultimate displacements when the quasi-static loading displacement exceeded the yield displacement; the reinforced concrete beam-column joint had stronger energy dissipation capacity in the face of cyclic loads; the reinforced concrete beam-column joint had smaller relative column displacements in the face of an eight-degree earthquake.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.107
Issue No: Vol. 16, No. 2 (2022)
- Vector Control of Permanent Magnet Synchronous Motor Based on MRAS Method
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Authors: X. Y. Xu, Y. Z. Li
Pages: 119 - 135
Abstract: In recent years, the application range of electric energy in modern industry has gradually expanded. Permanent magnet synchronous motor has the characteristics of high efficiency and energy saving, and has obvious advantages in traction application. In order to achieve good vector control of permanent magnet synchronous motor in the full speed range, Research on model reference adaptive system (MRAS) and pulsating high frequency injection method to construct the permanent magnet synchronous motor vector control system, and combined with the flux weakening control algorithm to control the motor under the condition of limited inverter output, so as to realize the sensorless vector control of the motor in the full speed range. The difference between the estimated value of the algorithm and the actual value is compared on the actual experimental platform to verify the feasibility of the control algorithm. The experimental results show that, Under medium and high-speed working conditions, the motor speed and rotor position tracking accuracy of MRAS algorithm is high, and the tracking error is less than 0.01rad. The pulsating high-frequency injection method can accurately track the permanent magnet synchronous motor under low-speed working conditions, the speed error is less than 1n / R / min, and the rotor position error is less than 0.03rad. The static and dynamic performance of the control system is good, It can better deal with the sudden change of motor load. Using MRAS algorithm and pulsating high frequency injection method to control permanent magnet synchronous motor in full speed range is of great significance to improve the speed control performance of permanent magnet synchronous motor.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.119
Issue No: Vol. 16, No. 2 (2022)
- Optimized Design of Oil-Water Separator for Injection and Production in
the Same Well
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Authors: J Fan
Pages: 137 - 146
Abstract: To realize the injection and production technology in the same well for high-water-cut oil wells, the multicup isoflux oil-water separator was optimized and designed according to the separation principle similar to multicup isoflux gas anchor. In the design process, the number of openings and apertures in each layer of the separator increased step by step from top to bottom, the liquid intake of each liquid inlet was similar, and the residence time of each produced liquid in the separator was long enough. Through the analysis of the optimal combination of different segmentation methods, the number of openings and different apertures, considering the requirements of machining, parameters such as aperture size, aperture classification and the number of openings were optimized according to the principle of fluid dynamics. While ensuring that the residence time of produced liquid in the settling cups at each part exceeds 150s, this design gives full play to the role of settling cups, effectively shortens the length of downhole oil-water separator, and saves production and operating costs.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.137
Issue No: Vol. 16, No. 2 (2022)
- On the Investigation of the Effect of Tower and Hub Exclusion on the
Numerical Results of a Horizontal Axis Wind Turbine
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Authors: M AbdulRaouf, E AlBahkali, S Parvez, A Alnhdi, M Souli, T AlBahkali
Pages: 147 - 173
Abstract: In order to construct a 3D rotor model, periodicity and Multiple Reference Frame (MRF) strategies were applied to address full Computational Fluid Dynamics (CFD) that incorporate the Reynolds-averaged Navier–Stokes (RANS) equations. A simulation model was run to examine the power of the wind turbines, both including and excluding the hub and tower. The purpose of this was to identify an approach that would decrease the computational time cost of wind turbine simulation. Firstly, a full-scale horizontal axis wind turbine simulation was carried out, and subsequently, comparisons were made with the results of the wind tunnel experiment utilizing the K-omega SST and Sparlat Allmaras viscosity models. The results were compared to determine the optimum model with the lowest simulation time and highest accuracy to the experimental results. Following this, the complete models’ simulation was compared to the model excluding the hub and tower in order to check the disparity in the results of the two. Additionally, to ascertain the computational cost saving, the ratio of the two simulation times was established. The findings show that the two models produce results that correspond well to the experimental results, and that the power coefficient had a greater value for the complete model than the simple model. Furthermore, it was found that the power coefficient values of the full model have significantly higher levels of similarity to the experimental values. The Sparlat Allmaras and K-omega SST viscosity models returned error percentages of 0.52% and 12.6% respectively. For the partial model utilizing the same computer device, a 5.7% error rate was recorded, with a computational time saving of approximately 34%.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.147
Issue No: Vol. 16, No. 2 (2022)
- Numerical Study of Viscous Fingering in Heterogeneous Porous Media
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Authors: H Djebouri, S Zouaoui, K Mohammedi
Pages: 175 - 186
Abstract: The displacement of a fluid by a second immiscible fluid is a fundamental process which is relevant for many technological applications, particularly in the petroleum industry. Water is the fluid widely used to push oil to production wells. During this immiscible displacement, a viscous fingering instability appears at the water-oil interface. This undesirable phenomenon leads to a low oil sweeping efficiency. To prevent this situation, techniques called EOR (Enhance Oil Recovery) are used. These methods have technical, economic and environmental disadvantages. Therefore, the objective of this work is to seek a rational use of EOR techniques by determining the right place and the appropriate time to operate them. In many previous studies, the effects of viscosity ratio, interfacial tension and flow rate are investigated. In this study, we numerically investigate the effect of the heterogeneity of the medium and the presence of the fracture on this phenomenon. Three different configurations are studied. The obtained results allowed to locate the regions where the behaviour of the instability varies during displacement in the porous medium, regions where instability is increasing and others where it remains constant. a qualitative comparison between the different cases is also made.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.175
Issue No: Vol. 16, No. 2 (2022)
- Determining Thermal Properties of Polyurethane by Solving the Heat
Equation and IR Imaging
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Authors: H Norum, Z Andleeb, H Khawaja, M Moatamedi
Pages: 187 - 202
Abstract: All materials have different and unique thermal properties that determine how the temperature changes when a material is subjected to a temperature difference. This study was intended to investigate the thermal properties of a polymer called Polyurethane, focusing on anti-seepage and anti-abrasion polyurethane. The thermal conductivity and heat transfer coefficient of cold polyurethane specimens have been calculated by capturing the infrared signature using a FLIR T1030sc Infrared camera and comparing the results with simulated results. The simulations were carried out in MATLAB®, and the solution is based on the Heat equation. This paper describes the driving mechanisms behind the Heat equation and how the approximated solution to the Heat equation is obtained by discretizing through a forward-time central-space (FTCS) finite-difference method. The results reveal that the heat transfer coefficient for anti-abrasion Polyurethane is almost four times that for anti-seepage Polyurethane. The thermal conductivity for the respective has a difference of a factor of two. A good agreement between the experimental and the numerical study was acheived. This study is helpful for the potential use of polyurethane material in Arctic regions either as a coating material for pipes or as a sealent in the oil and gas industry.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.187
Issue No: Vol. 16, No. 2 (2022)
- Comparison and Evaluation of Numerical Techniques and Physico-Chemical
Algorithms for the Simulation of an Iodine and Xenon Powered Ion Thrusters
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Authors: I Gomez, C Toomer
Pages: 203 - 221
Abstract: An electrostatic ion thruster, modelled on Busek’s BIT-3 [5], is simulated numerically using the open-source software “Starfish”. It is assumed that the thruster is in vacuum conditions propelling a CubeSat in low Earth orbit. Iodine is chosen here as the propellant under test. The results from modelling this relatively recent new fuel are compared to those of the standard propellant of xenon. The plasma in the ion thruster and the associated electric fields are simulated using a particle-based kinetic code in which the hybrid approach of Particle in Cell and Direct Simulation Monte Carlo methods has been used. In modelling these flows, elastic and inelastic collisions can occur involving charge and momentum exchanges. Such collision models use a number of assumptions, e.g., concerning the collisional cross-section area, and in this paper, we present results where the physico-chemical modelling is improved reducing the level of assumptions used. Results are also presented concerning the numerical methods used for the iterative convergence scheme, stochastic sampling, and the importance of the constraints for the mesh size and timestep. It is found that the most appropriate timestep is one which enables both the CFL condition and the highest frequency to be captured. The mesh size affects the choice of the solver being used; the largest the cell sizes the greater the assumption of quasi-neutral flow and thus areas of non-neutrality (such as in the surrounding shealth may be treated inadequately. The subsequent effects on the plume and the thrust produced of using different approaches in modelling the electron temperature distribution are also evaluated to produce a more rigorous modelling methodology.
PubDate: 2022-06-27
DOI: 10.21152/1750-9548.16.2.203
Issue No: Vol. 16, No. 2 (2022)
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Hybrid journal * Containing 7 
