scholarly journals Development and Parameters Analysis of Hydraulic Controlled Rotary Valve Excitation System

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3905
Author(s):  
Wenjing Li ◽  
Guofang Gong ◽  
Yakun Zhang ◽  
Jian Liu ◽  
Yuxi Chen ◽  
...  
Keyword(s):  
Simulation Model ◽  
Numerical Simulations ◽  
Electric Motor ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Rotary Valve ◽  
Excitation System ◽  
Coupling Relationship ◽  
Parameters Analysis ◽  
Relationship Of

Electro-hydraulic excitation systems are key equipment in various industries. Electric motor driving rotary valves are mostly used in existing systems. However, due to the separate design of the driving and hydraulic parts, highly compact integration cannot be achieved by these type of systems. Moreover, investigation on the influence of relevant parameters on the system has been insufficient in previous studies. To overcome these problems, a novel full electro-hydraulic excitation system scheme as well as a parameters analysis are presented in this paper. Theoretical models of the flow areas for valve orifices of different geometric shapes are obtained, based on which an AMESim® simulation model of the system is established. The effects of the main parameters are analyzed using numerical simulations, and the coupling relationship of the parameters is revealed. The results demonstrate the feasibility and effectiveness of the proposed method. Experimental studies were conducted to verify the effectiveness of the proposed system scheme and the analysis results. We found that a highly compact integration can be obtained while maintaining a high reversing frequency. We also found that the proposed system has a certain level of load adaptability, which is superior to the existing methods.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Mechanical Performance Simulation Model Based on PDM

2013 ◽  
Vol 300-301 ◽  
pp. 32-35
Author(s):  
Xiao Wen Zeng ◽  
Cheng Zeng ◽  
Bing Han
Keyword(s):  
Simulation Model ◽  
Mechanical Performance ◽  
Product Structure ◽  
Dynamics Simulation ◽  
Simulation Data ◽  
Performance Simulation ◽  
Collaborative Simulation ◽  
Complex Simulation ◽  
Mechanical Dynamics ◽  
Relationship Of

In order to manage the complex simulation data management in the process of mechanical dynamics simulation, a new management model was presented which is Performance Simulation Model(PSM). The model was based on PDM product structure and the concepts and elements of PSM were defined in this paper. Furthermore, the functional framework of PSM was proposed which based on the hierarchical relationship of product structure and the data stream relationship of data structure matrix. Finally, PSM was applied on ship planetary reducer collaborative simulation platform. The result indicates that the simulation data in mechanical collaborative simulation are managed by PSM, and the problem of interaction between collaborative simulation and PDM is solved.

Vortex-Induced Vibrations of a Cylinder at Subcritical Reynolds Number

2011 ◽  
Author(s):  
Yoann Jus ◽  
Elisabeth Longatte ◽  
Jean-Camille Chassaing ◽  
Pierre Sagaut
Keyword(s):  
Reynolds Number ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Cross Flow ◽  
Physical Analysis ◽  
Arbitrary Lagrangian Eulerian ◽  
Vortex Induced Vibrations ◽  
Low Mass

The present work focusses on the numerical study of Vortex-Induced Vibrations (VIV) of an elastically mounted cylinder in a cross flow at moderate Reynolds numbers. Low mass-damping experimental studies show that the dynamic behavior of the cylinder exhibits a three-branch response model, depending on the range of the reduced velocity. However, few numerical simulations deal with accurate computations of the VIV amplitudes at the lock-in upper branch of the bifurcation diagram. In this work, the dynamic response of the cylinder is investigated by means of three-dimensional Large Eddy Simulation (LES). An Arbitrary Lagrangian Eulerian framework is employed to account for fluid solid interface boundary motion and grid deformation. Numerous numerical simulations are performed at a Reynolds number of 3900 for both no damping and low-mass damping ratio and various reduced velocities. A detailed physical analysis is conducted to show how the present methodology is able to capture the different VIV responses.

Crashworthiness Performance of Mass-Efficient Extruded Structures

2002 ◽  
Author(s):  
Robert R. Mayer ◽  
Weigang Chen ◽  
Anil Sachdev
Keyword(s):  
Numerical Simulations ◽  
Single Cell ◽  
Experimental Testing ◽  
Experimental Studies ◽  
Nonlinear Material ◽  
Dynamic Strain ◽  
Cell Design ◽  
Explicit Finite Element ◽  
The One ◽  
Crushing Behavior

Theoretical, numerical and experimental studies were conducted on the axial crushing behavior of traditional single-cell and innovative four-cell extrusions. Two commercial aluminum alloys, 6061 and 6063, both with two tempers (T4 and T6), were considered in the study. Testing coupons taken from the extrusions assessed the nonlinear material properties. A theoretical solution was available for the one-cell design, and was developed for the mean crushing force of the four-cell section. Numerical simulations were carried out using the explicit finite element code LS-DYNA. The aluminum alloy 6063T4 was found to absorb less energy than 6061T4, for both the one-cell and four-cell configurations. Both 6061 and 6063 in the T6 temper were found to have significant fracture in the experimental testing. Theoretical analysis and numerical simulations predicted a greater number of folds for the four-cell design, as compared to the one-cell design, and this was confirmed in the experiments. The theoretical improvement in energy absorption of 57% for the four-cell in comparison with the one-cell design was confirmed by experiment. The good agreement between the theoretical, numerical and experimental results allows confidence in the application of the theoretical and numerical tools for both single-cell and innovative four-cell extrusions. It was also demonstrated that these materials have very little dynamic strain rate effect.

scholarly journals Determination of inductances for pulsating current traction motor

2021 ◽  
Vol 2 (1(58)) ◽  
pp. 40-43
Author(s):  
Sergey Goolak ◽  
Viktor Tkachenko ◽  
Svitlana Sapronova ◽  
Oleksandr Spivak ◽  
Ievgen Riabov ◽  
...  
Keyword(s):  
Electric Motor ◽  
Reactive Power ◽  
Country Of Origin ◽  
Experimental Studies ◽  
Active Power ◽  
Nonlinear Dependence ◽  
Power Losses ◽  
Electrical Parameters ◽  
Traction Motor ◽  
Pulsating Current

The object of research is a pulsating current traction motor. To improve the accuracy of its mathematical model, it is necessary to use the values of the parameters that are determined in experimental studies of the electric motor. In particular, it is important to use in the model of the electric motor inductance obtained experimentally. A method is proposed for calculating the inductance of the armature winding, main poles, additional poles and compensation winding and the total inductance of the traction motor armature circuit. The calculations are based on the results of the indirect inductance measurement method, in which the electrical values of various modes of power supply of the electric motor windings are directly measured, and the inductances are determined by auxiliary calculations. The inductances of the traction motor armature circuit have a non-linear dependence on the current flowing through them. The main difference of the study is that the measurements of the electrical parameters required for calculating the inductance are carried out over the entire range of operating currents of the windings. The essence of the proposed technique is to measure the active power in the armature winding, the winding of the main and additional poles, and the compensation winding, as well as in the armature circle as a whole when they are supplied with alternating current. According to the obtained values of active power losses and phase displacement, the corresponding reactive power losses are determined, with the help of which the inductances of the motor windings are calculated. Approbation of the methodology for calculating the conduction inductance for an electric motor of a pulsating current NB-418K6 (country of origin Russia), is used on electric locomotives of the VL80T and VL80k series (country of origin Russia). A scheme for measuring electrical parameters necessary for calculating inductance is proposed. The graphical dependences of the inductance on the armature current, built on the basis of calculations, confirmed the hypothesis about the nonlinear dependence of these inductances on the armature current. For further application of the results obtained in the simulation of the operation of the traction electric motor NB-418K6, a polynomial approximation of the total inductance of the armature circuit was performed.

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