Rotational Speed Of Rotor Research Articles

Совершенствование проточной части газосепараторов с использованием мультифазного коэффициента относительной скорости движения дискретных частиц

The paper analyzes features of the flowing formation fluid that contains free gas bubbles in the flow part of a vortex-type separator with the movable screw. Expressions are derived for a dimensionless multiphase coefficient of the discrete particles relative separation rate and the multiphase similarity criterion, which are making it possible to evaluate the gas separator efficiency, design and develop new devices based on the previously created highly efficient models. The derived equations allow determining the main geometric dimensions of the gas separator flow part based on the given radial dimensions, nominal flow rate and permissible content of free gas at the inlet. For the obtained geometric dimensions of the gas separator flow part, it becomes possible to construct dependences of the separation coefficient and the permissible amount of free gas at the inlet on the rotor rotation speed, flow rate and physical properties of the multiphase mixture.

Study on the wall-approaching film formation characteristics of water injected in a single screw steam compressor

To investigate the wall-approaching film formation (WAFF) mechanism of water injected during the compression process of single screw compressor, then to realize reasonable control of water injection parameters, a numerical simulation of water and steam two-phase flow inside the compression chamber during the compression process was carried out. The WAFF characteristics of water injected inside the compression chamber and the influence laws of the key parameters such as water injection angle (IA), injection velocity (IV), injection mass flow rate (IMFR), screw rotor rotational speed (SRRS) and injection hole spatial position (IHSP) on the WAFF characteristics were analyzed. The results show that the water injected into the chamber forms a water film by approaching the wall. With the increase of IA and IV, the effective water film average thickness (EWF-AT) and surface area (EWF-SA) show an increasing trend. In the process of IMFR growth, EWF-AT and EWF-SA exhibit maximum values. Considering the goal of minimizing the injection power consumption, the IA of 70°, IV of 30 m·s−1 and IMFR of 0.3 kg·s−1 were determined as the optimal water injection parameters. Selecting the appropriate IMFR, SRRS and IHSP will effectively increase EWF-AT and EWF-SA, then to prevent leakage.

Evaluation of magnetic gear parameters for autonomous wind installation with changing wind speed

Purpose. To evaluate the parameters and characteristics of the magnetic gearbox at constant and variable wind speed as part of an autonomous wind power plant. Methodology. Analysis of existing methods of mathematical modeling of magnetic gearboxes. Numerical methods of mathematical modeling based on finite elements. Numerical methods of processing the obtained results. Findings. A two-dimensional field mathematical model has been developed to estimate the parameters and characteristics of the magnetic gearbox at variable and constant wind speed. With the help of the developed model, the electromagnetic field, parameters and characteristics of the magnetic gearbox were analyzed both at a constant and at a variable speed of rotation. In particular, it was found that the magnetic system of the reducer does not reach saturation, while the average values of magnetic induction in the structural elements of the reducer remain within the permissible values for the used materials and grades of steel. The obtained data on the average values of the electromagnetic moments of the outer (high-speed) rotor and the inner rotor make it possible to understand the relationship between them and their influence on the operation of the system. A conclusion was made about the uneven distribution of induction along the middle line in the air gap, which is caused by the presence of a modulator in the design of the reducer. In addition, according to the obtained results, the change in wind speed affects the speed of rotation of the magnetic gearbox and the magnitude of the electromagnetic moments of the high-speed and low-speed rotors. Such information helps to understand the dynamics of system operation under different environmental conditions. The results obtained in the study are important for further improvement of the magnetic reducer design and ensuring more efficient operation of the low-power wind turbine. They can be used to optimize the structure and increase its productivity, which will contribute to the development of wind energy and the green energy industry in general. The average value of the electromagnetic moment of the outer (high-speed) rotor is about 7.4 N∙m, while for the inner rotor the value of the electromagnetic moment is about 66 N∙m. The ratio of the moments of the outer and inner rotors is 8.92, which correlates with the reduction factor of the gear under study. Originality. A two-dimensional field mathematical model has been developed, which takes into account the change in the parameters and characteristics of the magnetic gearbox when the wind speed changes and the random rotation speed of the wind generator rotor. Practical value. The results of the research of the magnetic reducer for a low-power wind turbine have an important contribution to the development of wind energy, contribute to increasing the efficiency and reliability of energy production, and contribute to the creation of a more sustainable and environmentally friendly energy complex.

Experimental evaluation of phase and velocity control for a cyclorotor wave energy converter

The research presented in the paper is dedicated to the analysis of the 3D experimental testing results of a 1:20 scale prototype LiftWEC cyclorotor wave energy converter (WEC). The scaled prototype was built and tested in the Hydraulic and Offshore Engineering wave Tank (HOET) by Ecole Centrale Nantes (ECN) in 2022. The analysis is conducted using the analytical control-oriented point-vortex model. The presented research covers a range of tests, with particular focus on cases where positive mechanical power generation has been recorded. The analysis of such cases is important, in highlighting the conditions needed for optimum energy conversion, for future development of cyclorotor WEC technology. The study also reviews the results of tests where the rotor rotational speed is varied within each period of monochromatic waves. This is the first experimental test of such a control strategy for cyclorotor WECs.

Study of Permanent Magnet Synchronous Motor With LQG Controller and Observer On The Hydraulic Pump System

In today's aircraft industry, the flight control system and landing gear system cannot be separated from the role of the hydraulic technology system. As the prime mover of the hydraulic pump or actuator hydraulic system, a permanent magnet synchronous motor (PMSM) is used. This PMSM is a substitute for the role of conventional combustion engines, and PMSM is considered to have several advantages in increasing performance and efficiency. This research will develop a system to find parameter values for Linear Quadratic Gaussian (LQG) controllers in a hydraulic pump system that is installed as a load from PMSM and then observe and analyze the performance of the response of the synchronous motor system, namely in the form of changes in rotor rotation speed, torque electric power, and stator current on the q-axis. The results of the research on the characteristics of the PMSM implemented in the hydraulic pump system show that the LQG controller is more optimal when compared to the observer controller. The LQG controller is known to have a faster transient response, which is indicated by the value of the settling time improvement at no load, namely 116.67% for the observer controller and 364.705% without the controller. Then when the synchronous motor serves the nominal load, the rotational speed of the rotor produced in the steady state becomes 8.29% faster than the observer controller and 74.49% without the controller. This rotor's rotational speed affects the time the actuator needs to extend and retract motion.

Experimental Study and 3D Optimization of Small-Scale Solar-Powered Radial Turbine Using 3D Printing Technology

Small-Scale Turbines (SSTs) are among the most important energy-extraction-enabling technologies in domestic power production systems. However, owing to centrifugal forces, the high rotating speed of SSTs causes excessive strains in the aerofoil portions of the turbine blades. In this paper, a structural performance analysis is provided by combining Finite Element Methods (FEM) with Computational Fluid Dynamics (CFD). The primary objective was to examine the mechanical stresses of a Small-Scale Radial Turbine (SSRT) constructed utilizing 3D printing technology and a novel plastic material, RGD 525, to construct a SSRT model experimentally. After introducing a suitable turbine aerodynamics model, the turbine assembly and related loads were translated to a structural model. Subsequently, a structural analysis was conducted under various loading situations to determine the influence of different rotational speed values and blade shapes on the stress distribution and displacement. Maximum von Mises and maximum main stresses are significantly affected by both the rotor rotational speed and the working fluid input temperature, according to the findings of this research. The maximum permitted deformation, on the other hand, was more influenced by rotational speed, while the maximum allowable fatigue life was more influenced by rotating speed and fluid intake temperature. Also, the region of the tip shroud in the rotor had greater deflection values of 21% of the blade tip width.

Improvement of the Airflow Energy Harvester Based on the New Diamagnetic Levitation Structure.

This paper presents an improved solution for the airflow energy harvester based on the push-pull diamagnetic levitation structure. A four-notch rotor is adopted to eliminate the offset of the floating rotor and substantially increase the energy conversion rate. The new rotor is a centrally symmetrical-shaped magnet, which ensures that it is not subjected to cyclically varying unbalanced radial forces, thus avoiding the rotor's offset. Considering the output voltage and power of several types of rotors, the four-notch rotor was found to be optimal. Furthermore, with the four-notch rotor, the overall average increase in axial magnetic spring stiffness is 9.666% and the average increase in maximum monostable levitation space is 1.67%, but the horizontal recovery force is reduced by 3.97%. The experimental results show that at an airflow rate of 3000 sccm, the peak voltage and rotation speed of the four-notch rotor are 2.709 V and 21,367 rpm, respectively, which are 40.80% and 5.99% higher compared to the three-notch rotor. The experimental results were consistent with the analytical simulation. Based on the improvement, the energy conversion factor of the airflow energy harvester increased to 0.127 mV/rpm, the output power increased to 138.47 mW and the energy conversion rate increased to 58.14%, while the trend of the levitation characteristics also matched the simulation results. In summary, the solution proposed in this paper significantly improves the performance of the airflow energy harvester.

Thermal Characteristic Analysis of Fully Superconducting Motors Employing Dilute Gas Rotor Cooling Structure

We have proposed a rotor cooling structure using dilute gas for a fully superconducting motor for aircraft application. Numerical analysis was performed to investigate the feasibility of the proposed cooling method and structure, which can make a fully superconducting motor lighter and more compact than a partially superconducting motor. The helium gas pressure in the gap, the rotor rotational speed, and the rotor loss are key parameters of the cooling, and thermal analysis was performed to clarify the dependence of the field winding temperature on these parameters. In the analysis, the motor model has the maximum output of 5.5 MW and the maximum speed of 5000 rpm. The superconducting armature windings are cooled down to 20 K by conduction cooling with liquid hydrogen, and the superconducting field winding is cooled down to about 50 K indirectly using helium gas in the gap. Numerical analysis results indicate that the helium gas pressure should be increased when the rotor loss is larger, but if the pressure is increased too much, the temperature of the field winding becomes higher due to wind loss. When the rotor loss is several hundred watts, the helium gas pressure should be in the range of 104 to 105 Pa.

A novel experimental control method to suppress instability in a centrifugal compressor with two counter and co-rotating rotors

The use of a counter-rotating rotor in turbomachines can be a solution to improve performances by allowing reduction in size and weight, especially compared to multistage configuration. The present study aims are to demonstrate another advantage of the counter-rotating rotors: their application to expand the operating range of centrifugal compressors toward extremely low flow rates based on an active control method. This method was performed on two different counter-rotating configurations. The principle of the active control method is to adjust independently the rotation speed of each rotor to push back the instability appearance. Experimental results show that reducing the rotation speed of the upstream-rotor while fixing the speed of the downstream rotor can push the instability phenomenon toward a lower mass flow rate while decreasing the pressure rise and efficiency. Co-rotating mode is applied to push further the stable region toward low mass flow rates allowing a significant extension of the operating range. The experimental results reveal that the map width is shifted by about 50% over the studied range toward a lower mass flow rate for both counter-rotating centrifugal compressors when using the control method. This can be achieved when the absolute value of the upstream-rotor speed is within the range of 48%–61% of the rotational speed of the downstream rotor.

Spectrum characteristics and temperature measurement error of FBG sensor based on rotor temperature monitoring system

For real-time temperature monitoring of a generator or electric motor rotor, the effects of rotation on the reflection spectrum of a polyimide-coated Fibre Bragg Grating (FBG) were analyzed using formulas. The measurement error resulting from the low-speed operation was evaluated, combined with the finite element method. Secondly, the key design of the FBG sensors and the mating part of the fiber optic rotary joint (FORJ) were investigated. The temperature of a rotating shaft was monitored to test the reliability of the measurement system. With a resolution of 0.1℃, the system was able to achieve an error of 0.5℃ over a range of 30-180℃. Finally, the critical conditions for the application of polyimide-coated and metal-coated FBGs were discussed. The results show that the variation of the center wavelength is more sensitive to the radius of the small-sized rotor, and the rotation speed of the large-sized rotor. It is at higher speeds that the thickness of the coating has a more pronounced effect on error, demonstrating that the accuracy of FBGs used in high-speed rotors could be rapidly improved by reducing the thickness of the metal coating. The reported results provide a basis for the thermal monitoring performance of FBG sensors during rotation.

Research on operating characteristics of single-spool turbojet enginewith the afterburner AL-21F

The single-spool, single-thread, turbojet engine with afterburner AL-21F has been used on fighter aircraft for a long time, but there are few studies on this engine in Vietnam. This article uses the theoretical approach, calibrates according to the technical description and actual operation, combined with specialised software such as GasTurb and GSP to calculate engine thermodynamic parameters in some actual flight conditions. The obtained results showed that, when the flight speed increases, the specific fuel consumption increases linearly, while the initial engine thrust decreases and reaches the minimum value at M=0.3÷0.5, then continue to increase and reach the maximum at the speed limit. When increasing the height, the speed and regulating spool speed of the engine remain the same, the engine thrust decreases as well as the specific fuel consumption increases. When increasing the rotor rotation speed, the engine thrust increases linearly but the specific fuel consumption decreases gradually and remains almost the same at engine rpm above 85%. The results allowed for a better understanding of the operating process of the AL-21F engine in particular and turbojet engines in general or used to build simulation models operating close to reality.

Wind-Tunnel Experiments on the Interactions among a Pair/Trio of Closely Spaced Vertical-Axis Wind Turbines

To elucidate the wind-direction dependence of the rotor performance in closely spaced vertical-axis wind turbines, wind-tunnel experiments were performed at a uniform wind velocity. In the experiments, a pair/trio of three-dimensional printed model turbines with a diameter of D = 50 mm was used. The experiments were performed systematically by applying incremental adjustments to the rotor gap g and rotational direction of each rotor and by changing the wind direction. For tandem layouts, the rotational speed of the downwind rotor is 75–80% that of an isolated rotor, even at g/D = 10. For the average rotational speed of the rotor pair, an origin-symmetrical and a line-symmetrical distribution are observed in the co-rotating and inverse-rotating configurations, respectively, thereby demonstrating the wind-direction dependence for the rotor pair. The inverse-rotating trio configuration yields a higher average rotational speed than the co-rotating trio configuration for any rotor spacing under the ideal bidirectional wind conditions. The maximum average rotational speed should be obtained for a wind direction of θ = 0° in the inverse-rotating trio configuration. The wind-direction dependence of the rotational speeds of the three turbines was explained via flow visualization using a smoke-wire method and velocity field study using two-dimensional computational fluid dynamics.

Thermal Effects in the End-Winding Region of Electrical Machines

The main heat transfer mechanism in the end-winding region of electrical machines is convection. In order to increase the air motion, the rotor is equipped with a series of blades. Their geometry is reflected in the fanning factor, i.e., the ratio between the rotor peripheral speed and air velocity. An accurate calculation procedure for the fanning factor has not yet been given. Knowing its value is crucial for the determination of air velocity and heat transfer coefficient (HTC), as the latter describes the end-winding heat removal capability. In this study, the convective heat transfer phenomena between the end winding and air inside the end-winding region were analyzed, with the heat generated only in the end winding, mimicked with a custom designed coil, and air moved by the blades. The analysis was performed by experimental testing and computational fluid dynamics (CFD) modeling. Measurements data were used to build a reliable CFD model. Further on, CFD results were used to derive a generalized analytical equation for calculation of the end-winding HTC, related to blade geometry and rotor rotational speed. The developed analytical model significantly improves the quality of real-time lumped circuit thermal modeling of electrical machines and, thus, enriches this field of science.

Evaluation of a Coating Process for SiO<sub>2</sub>/TiO<sub>2</sub> Composite Particles by Machine Learning Techniques

In this study, in order to optimize a fabrication process for SiO2/TiO2 composite particles and control their coating ratio (CTi), regression models for the coating process were constructed using various machine learning techniques. The composite particles with a core (SiO2)/shell (TiO2) structure were synthesized by mechanical stress under various fabrication conditions with respect to the supply volume of raw materials (V), addition ratio of TiO2 (rTi), operation time (t), rotor rotation speed (S), and temperature (T). Regression models were constructed by the least squares method (LSM), principal component regression (PCR), support vector regression (SVR), and the deep neural network (DNN) method. The accuracy of the constructed regression models was evaluated using the determination coefficients (R2) and the predictive performance was evaluated by comparing the prediction coefficients (Q2). From the perspective of the R2 and Q2 values, the DNN regression model was found to be the most suitable model for the present coating process. Moreover, the effects of the fabrication parameters on CTi were analyzed using the constructed DNN model. The results suggested that the t value was the dominant factor determining CTi of the composite particles, with the plot of CTi versus t displaying a clear maximum.

Technological methods of improvement and influence on the rotor rotation speed on efficiency of barley hushing machine

The article provides the results of a study of the impact of different parameters and the process of peeling barley in the production offeed. Theoretical studies and analysis of the structures of the peelers and the proposed horizontal peeler have suggested that the rational rotation rate of the rotor during barley peeling will be between 1500 and 1800 rpm. After the studies, a number of factors were tested which influenced and increased the efficiency of barley peeling, which determined the effect of rotor rotation frequency, processing duration, the amount of product pass through processing during, the peeler. Based on the research, the technological parameters of the peeler have been developed andimproved.

ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ И РАСЧЕТ ХАРАКТЕРИСТИК МАГНИТОЭЛЕКТРИЧЕСКОГО СИНХРОННОГО ГЕНЕРАТОРА НА БАЗЕ АСИНХРОННОЙ МАШИНЫ

The article conducts a study of the developed prototype of a permanent magnet synchronous generator (PMSG) based on simulation modeling and experimental tests. To conduct experimental studies, a test stand has been developed with the ability to regulate the rotation speed of the PMSG rotor up to 500 rpm. The prototype is a three-phase synchronous machine, the stator magnetic system is based on the stator magnetic system of an asynchronous electric machine

ИСПОЛЬЗОВАНИЕ ЧАСТОТНОГО СПОСОБА РЕГУЛИРОВАНИЯ ОБОРОТОВ АСИНХРОННОГО ДВИГАТЕЛЯ В КАЧЕСТВЕ ИМИТАТОРА ВЕТРОКОЛЕСА ВЕТРОЭНЕРГЕТИЧЕСКОЙ УСТАНОВКИ

The article conducts a study of the developed prototype of a permanent magnet synchronous generator (PMSG) based on simulation modeling and experimental tests. To conduct experimental studies, a test stand has been developed with the ability to regulate the rotation speed of the PMSG rotor up to 500 rpm. The prototype is a three-phase synchronous machine, the stator magnetic system is based on the stator magnetic system of an asynchronous electric machine

Introducing Improved Iterated Extended Kalman Filter (IIEKF) to Estimate the Rotor Rotational Speed, Rotor and Stator Resistances of Induction Motors

This paper introduces the Improved Iterated Extended Kalman Filter (IIEKF) for estimating the rotational speed, rotor resistance, and stator resistance of three-phase induction motors (IMs). Two state-space models for estimating the variables are presented. An optimal estimation of rotational speed is obtained by introducing a data fusion approach. The effectiveness of the IIEKF in comparison with the Extended Kalman Filter (EKF), using experimental data and in a wide range of operating conditions, is shown.

Evaluation of the pattern of spray released from a moving multicopter.

Multicopters are used for releasing particulates seeds, fertilizer and spray. Their low cost and high manoeuvrability make them attractive for spraying in steep terrain and areas where overspray is undesirable. This article describes a model of multicopter wake and its influence on particulate dispersion, which is computationally economical compared to many computational fluid dynamics (CFD) approaches, yet retains reasonable accuracy. A model was successfully implemented in OpenFOAM. It features source terms for the rotor wash, Lagrangian particle tracking, an evaporation model, and a porous medium approach to model the effect of the ground vegetation. Predictions were validated against the field tests of Richardson et al. which used a DJI Agras MG-1 multicopter in three different flights with airspeeds of 3.2-4.9m s-1 , ground speeds of 2.1-2.9m s-1 and cross-wind speeds of 0.04-2.2m s-1 . The effective swath width (30% line separation) was predicted to within one standard deviation. Sensitivity to a rotor rotational speed, flight height, flight velocity, multicopter roll and yaw angles, surface roughness length, plant height and leaf density was checked. In all flight trials, the modelled swath was closest to the experimentally obtained swath when the surface roughness of the fetch was equal to 0.5m (bushes) and the rotational speed of all rotors was equal to 2475 rpm with 0.75R (0.2m) tall plant canopy (grass) introduced to the model. The model showed acceptable validity for flight velocities of ≤2.8-5m s-1 when flight parameters can be approximately estimated. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Desain Dan Simulasi Turbin Angin Savonius Dengan Konfigurasi Rotor Tipe L Dan Tipe Helix Sebagai Sumber Listrik Lampu PJU Pelabuhan Perikanan Cikidang Pangandaran Jawa Barat

Cikidang Fishing Port, Pangandaran, West Java is located in the southern region of Java island which is directly opposite the Indian Ocean which has the potential for energy development, one of which is from wind. Wind is one of the natural resources that can be used as an alternative power generation source as a substitute for conventional fuel. From the results of observations on the average wind speed for seven days of v = 4.8 m/s. Based on the results of observations, a vertical axis wind turbine, namely Savonius, is planned as the drive of the power plant generator, with configurations in the shape of the rotor, namely the L type and helix type. In type L with a diameter of 1.1 meters, a height of 1.4 meters can receive kinetic energy = 60.96 Joules which has the potential to produce a rotor power of 110.87 Watts. While in the Helix type with a diameter of 1.1 meters, a height of 1.4 meters can receive 82,63 Joules which has the potential to produce a rotor power of 159.32 Watts. In the static structural simulation, for the Savonius L type wind turbine rotor with Aluminum Alloy material, it showed a total deformation of 12.239 mm, an equivalent elastic strain of 2.1252 x 10-4 mm, and an equivalent stress of 14.973 MPa at a rotor rotation speed of 83.4 RPM with a wind thrust force of 25.4 Newton. The Savonius Helix type wind turbine rotor with Aluminum Alloy material showed a total deformation of 11.74 mm equivalent elastic strain of 1.5941 x 10-5 mm, and an equivalent stress of 18.75 MPa at a rotor rotation speed of 83.4 RPM with a wind thrust force of 34.43 Newton.