JUSTIFICATION OF ROTOR SPEED OF RADIAL HONEY SEPARATOR WITH THE HORIZONTAL FULCRUM PIN

2016 ◽  
Vol 1 (4) ◽  
pp. 51-54
Author(s):  
Сыркин ◽  
Vladimir Syrkin ◽  
Васильев ◽  
Sergey Vasilev
Keyword(s):  
Tangential Force ◽  
Rotation Frequency ◽  
Spin Axis ◽  
Geometrical Parameters ◽  
Belt Drive ◽  
Centripetal Force ◽  
Rotor Speed ◽  
Separator Rotor ◽  
Rotor Rotation Frequency ◽  
Rotor Axis

The purpose of research is increase in effectiveness of pumping of honey in the separator of radial type with a horizontal spin axis of a rotor. Use radial a separator allows to make honey pumping on both sides of a frame at once and places larger quantity of a frames. The radial separator consists of housing and a rotor. The rotor is set in motion via the belt drive manually or the electric motor. The rotation frequency of a rotor of a separator is the major technology factor influencing honey pumping process. With increase in a rotation frequency the centrifugal force providing a honey exit from honeycombs of a frame increases. The high rotation frequency of a rotor with a framework, can lead to destruction of a wax basis of a cellular frame. Low the rotation frequency can become the reason of inexact pumping of honey from honeycombs. In the course of centrifugation the honey which is contained in everyone unit is affected by the gravity, a centripetal force, tangential force of shift of layers of honey, force of reaction of walls of honeycombs. As a result of calculation it is established that the rotation frequency of a rotor depends on such parameters as viscosity of honey, geometrical parameters of honeycombs, distances of honeycombs from a separator rotor spin axis. In the course of work there will be first of all a honey honeycombs located further from a rotor axis. Decrease in cooperative weight of a frame will allow to keep its wholeness and to gradually increase a separator rotor rotation frequency.

Transmission Error Due to Resonance in Synchronous Belt Drive With Eccentric Pulley

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Masanori Kagotani ◽  
Hiroyuki Ueda
Keyword(s):  
Transverse Vibration ◽  
Rotation Frequency ◽  
Transmission Error ◽  
The Other ◽  
Belt Drive ◽  
Integer Multiple ◽  
Belt Drives ◽  
Eccentric Shaft ◽  
Synchronous Belt Drive ◽  
Frequency Variations

In synchronous belt drives, it is generally difficult to eliminate pulley eccentricity, because the pulley teeth and shaft hole are produced separately and the pulley is installed on an eccentric shaft. This eccentricity affects the accuracy of rotation transmission, so that the belt tension changes during a single rotation of the pulley. This in turn affects the occurrence of resonance in the spans. In the present study, the transmission error in a synchronous belt drive with an eccentric pulley in the absence of a transmitted load was experimentally investigated for the case in which the spans undergo first-mode transverse vibration due to resonance. The transmission error was found to have a component with a period equal to the span displacement, in addition to a component with a period of half the span displacement. During a single rotation of the pulley, the magnitude of the transmission error increased, and its frequency decreased, with decreasing belt tension. The transmission error exhibited the large value when two frequency conditions were satisfied: one was that the meshing frequency was within the range of span frequency variations due to the eccentricity, and the other was that the minimum span frequency was close to an integer multiple of the pulley rotation frequency. Even if both of these conditions occurred, if the range of span frequency variations due to the eccentricity was larger than 13 Hz, the transmission error could be eliminated by adjusting the belt tension, so that the average span frequency corresponded to the meshing frequency.

Increased Power Capture by Rotor Speed–Dependent Yaw Control of Wind Turbines

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Knud A. Kragh ◽  
Paul A. Fleming ◽  
Andrew K. Scholbrock
Keyword(s):  
Wind Turbines ◽  
Rotor Speed ◽  
Wind Speeds ◽  
Yaw Control ◽  
Correction Scheme ◽  
Power Capture ◽  
Horizontal Axis Wind Turbines ◽  
Power Yield ◽  
Additional Costs ◽  
Rotor Axis

When extracting energy from the wind using upwind, horizontal-axis wind turbines, a primary condition for ensuring maximum power yield is the ability to align the rotor axis with the dominating wind direction. Attempts have been made to improve the yaw alignment of wind turbines by applying advanced measurement technologies, such as light detection and ranging systems. However, application of advanced measurement equipment is associated with additional costs and increased system complexity. This study is focused on assessing the current performance of an operating turbine and exploring how the yaw alignment can be improved using measurements from the existing standard measurements system. By analyzing data from a case turbine and a corresponding meteorological mast, a correction scheme for the original yaw control system is suggested. The correction scheme is applied to the case turbine and tested. Results show that, with the correction scheme in place, the yaw alignment of the case turbine is improved and the yaw error is reduced to the vicinity of zero degrees. As a result of the improved yaw alignment, an increased power capture is observed for below-rated wind speeds.

scholarly journals The Analysis of Process of Crushing in the Vibrocavitational Homogenizer

2020 ◽  
Vol 9 (4) ◽  
pp. 53-58
Author(s):  
E. V. Flisyuk ◽  
S. S. Belokurov ◽  
I. A. Narkevich ◽  
O. M. Flisyuk ◽  
D. Yu. Ivkin
Keyword(s):  
Solid Phase ◽  
Raw Materials ◽  
Rotation Frequency ◽  
Biologically Active Substances ◽  
Biologically Active ◽  
Rotor Speed ◽  
Particle Crushing ◽  
Fenugreek Seeds ◽  
Average Probability ◽  
Active Substances

Introduction. Vibration cavitation homogenizers are increasingly used in various industries, including the pharmaceutical industry – for the preparation of creams, gels to give them a homogeneous composition, and more recently for the extraction of valuable substances from plant materials. As we have shown earlier, a comparison of the extraction of dioscin from fenugreek seeds, carried out in devices of various designs, under the same conditions for organizing the process showed that the most effective method was the extraction method in a vibro-cavitation field. Obviously, this is due to the fact that cavitation reduces the diffusion resistance of the process and, thus, increases the intensity of the process of transferring the mass of a substance from the solid phase to the solution. However, the extraction process in apparatus of this type is complex and is accompanied by crushing of seeds, which leads to a change in the dispersed composition of the solid phase.Aim. Conduct a theoretical and experimental analysis of the process of grinding hay fenugreek seeds particles in a vibrocavitation homogenizer, accompanied by the extraction of biologically active substances, as well as obtaining dependences that allow evaluating the contribution of grinding to the formation of the dispersed composition of the meal in this apparatus and determining the average particle size as a result of crushing. In earlier works, using the example of the extraction of dioscin from fenugreek seeds, it was shown that an increase in the rotor speed increases the yield of biologically active substances. However, fine grinding of raw materials often leads to the formation of a sediment layer that pollutes the solution with ballast substances and complicates its purification, and also reduces the yield of biologically active substances, therefore, the study of this process is necessary to control the dispersed composition in order to ensure the highest extraction efficiency in devices of this type.Materials and methods. The first stage of the study was the theoretical analysis of the grinding process, since it is a special case of a large class of processes in which the dispersed composition of the solid phase is not constant. Therefore, in this work, for the mathematical description of particle grinding, a model is used that takes into account the kinetic features of the process under consideration. An experimental study of the extraction of valuable components from plant raw materials was carried out in a laboratory setup with a vibro-cavitation homogenizer of periodic action. As a raw material, we used fenugreek seeds purchased from LLC «Stoing», Moscow (Russia), which we used for research. Commodity analysis showed the compliance of raw materials with the requirements of the GF XIV edition. The initial, aqueous solution of ethanol (volume concentration 60 %) with fenugreek seeds was loaded into glass 6, in a volume of 0.2 liters, then the rotor of the apparatus was brought into rotation and brought to a given rotation frequency. The experiments were carried out at a rotation frequency of 1000, 3000 and 5000 rpm (16.7; 50 and 83.3) 1/s. At each value of the rotor speed, the process time varied in the range from 0 to 50 minutes, and the process was carried out for 60, 120, 180, 240 and 300 seconds. Studies carried out for 5 minutes or more showed that the dispersed composition of the meal practically does not change over time, but significantly depends on the rotor speed. Thus, after 5 minutes, a certain stabilization of the dispersed composition occurs and further residence of the material in the apparatus does not lead to a noticeable change in the dispersed composition. After each experiment, the meal was taken, dried, and sieve analysis of the dispersed composition was carried out.Results and discussion. Based on the results obtained by processing the experimental data according to the equation, the values of the average probability of particle crushing were calculated and, as it turned out, it practically does not depend on time, but depends only on the rotor speed. The dependence of the change in the average probability of particle grinding at different rotor speed was obtained. The analysis of these results showed that the value of the average probability of particle grinding in the cavitation homogenizer increases with an increase in the rotor speed, which is quite expected, since the frequency of contacts of particles with the working organs of the apparatus increases. In addition, the obtained dependence for the average probability of particle crushing is linear. This Expression quite accurately describes the values of the change in time of the relative mass of particles in the working range n = 16.7 – 83.3 1/s. Taking these values into account, the experimental and calculated results are in good agreement.Conclusions. The proposed approach and the results obtained can be used to assess the dispersed composition of particles obtained in other designs of devices of similar action.

Speed-Torque Characteristics of Torque Motor with Tape Winding Stator

2021 ◽  
Vol 64 (1) ◽  
pp. 37-42
Author(s):  
Antonina Dolgih ◽  
◽  
Vladimir Martemyanov ◽  
Keyword(s):  
Rotation Frequency ◽  
Motor Speed ◽  
The Finite Element Method ◽  
Rotor Rotation ◽  
Dc Motors ◽  
New Type ◽  
Current Lines ◽  
Value Changes ◽  
Rotor Rotation Frequency ◽  
Motor Model

The speed-torque characteristics of a torque motor with a new type of active element – the tape winding is considered. The analytical studies of the motor speed-torque characteristics determination is difficult because it is required to take into account the distributed current flowing through the winding elements. This leads to the numerical methods application, in particular, COMSOL Multiphysics software based on the finite element method (FEM). Attention is paid to the changing of the motor developed torque in the presence of EMF created in the winding during the rotor rotation. It is shown that the motor torque with a rotor rotation frequency changing depends mainly on the nature of the distributed current lines flowing through the winding elements, despite the fact that the consumed current value changes to a lesser extent. The obtained speed-torque characteristics of the torque motor has a form similar to ones of separately excited DC motors. The research results allow assessing the expected characteristics of the motor model and are an integral part of the developed design policy of the torque motor with the tape winding stator.

A Hierarchical Model for Kevlar Fiber Failure

2013 ◽  
Author(s):  
Stephen S. Recchia ◽  
Assimina Pelegri ◽  
Jan K. Clawson ◽  
Korhan Sahin ◽  
Ioannis Chasiotis ◽  
...  
Keyword(s):  
Finite Element ◽  
Computational Models ◽  
Tangential Force ◽  
Average Diameter ◽  
Element Model ◽  
Experimental Information ◽  
Geometrical Parameters ◽  
Fiber Failure ◽  
Validation Data ◽  
Initial Modulus

Advances in materials characterization at the submicron and the nano-scales have progressed in the last decade. At the same time, computational capability for finite element analyses are also improving through technological developments in parallel computing. However, large computational models of nanostructured materials are currently limited by the lack of validation data. The work reported in this paper describes the formulation of a representative nanoscale model for Kevlar fibers based on failure section imaging that captures its fibril and microfibril structure. In this regard, a finite element model that captures the nanoscale structure of Kevlar fibers was developed to predict their macroscale response. Experimental derivation of geometrical parameters and physical properties of fibrils and microfibrils is challenging due to the sensitive nature of polymers. There are several microfibril parameters that reflect into effective fiber response, such as the microfibril constitutive behavior, length, diameter, shape, the inter-fibril shear and normal strength, and the inter-fibril normal and tangential force decay the after peak strength is achieved. This paper investigates the effect of each of the aforementioned parameters on the initial modulus, yield strength, ultimate strength, and strain rate dependence of Kevlar fibers with 10 μm average diameter. The sensitivity of the macroscale response to each microfibril parameter can be used to identify areas where experimental information can further enable the predictive capability of the computational model. A parametric study was performed to calculate the effective macroscale fiber response. Subsequently, a local gradient sensitivity method was employed to plot the sensitivity of the fiber response to each microfibril parameter.

Validating the Iterative Design Procedure for an Axial Flow Turbine Test Rig

2021 ◽  
Author(s):  
Rajat Arora ◽  
Ramraj H. Sundararaj ◽  
T. Chandra Sekar ◽  
Abhijit Kushari
Keyword(s):  
Mass Flow ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Secondary Flows ◽  
Working Fluid ◽  
Geometrical Parameters ◽  
Airflow Rate ◽  
Rotor Speed ◽  
Flowing Fluid ◽  
Air Mass

Abstract Turbines remain one of the most efficient devices for extracting energy from a flowing fluid. In a gas turbine engine, axial flow turbines are used to extract energy from the working fluid and drive the compressor, to which they are mechanically connected. To maximize the performance of the axial flow turbine, it is necessary to carry out a design optimization of the components while suitably accounting for losses generated by secondary flows. An axial flow turbine rig is designed, fabricated, and installed to better understand and improve upon secondary flow models used in design procedures. The rig is driven by a blower operating at a constant speed, capable of delivering a maximum airflow rate of 0.4 kg/s and a maximum pressure rise of 500 mbar across the device. The axial flow turbine is mechanically connected to a dynamometer capable of operating at a full load capacity of 5 kW and a maximum rotational speed of 10,000 RPM. The axial flow turbine, housed between the blower and dynamometer, consists of nozzle guide vanes followed by a rotor. The design pressure ratio is chosen as 1.04, based on the blower delivery conditions and dynamometer specifications. For an initial design, a low-pressure ratio low rotor speed design was selected, allowing for easy installation and testing of the rotating components. The design space for the axial flow turbine was generated by varying flow and geometrical parameters in suitable steps, using a program written in MATLAB 2020a. Using the input variables and applying free vortex theory for three-dimensional blade design, the aerodynamic design of the axial flow turbine was carried out. The axial flow turbine design is experimentally tested with suitable pressure measurements at every station. Experiments are conducted for four different air mass flow rates. At each air mass flow, the rotor speed is varied by increasing/decreasing the dynamometer load. The data is recorded and compared with the design point. The difference between the design and measured performance parameters is observed to be within acceptable limits.

Application of dc Servomotor on Airflow Measurement

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Thananchai Leephakpreeda
Keyword(s):  
Optimal Control ◽  
State Feedback ◽  
Angular Position ◽  
Control Design ◽  
Rotor Speed ◽  
H2 Control ◽  
Luenberger Observer ◽  
Torsional Load ◽  
Dc Servomotor ◽  
Rotor Axis

The aim of this research paper is to systematically present an optimal control of a dc servomotor for the airflow measurement in both the magnitude and the direction. During measuring airflow, the dc servomotor drives a paddle around the rotor axis in a field. The torsional load of the dc servomotor is caused from resistance of the airflow over the moving paddle normal to the flow. The variations on the torsional load in one revolution of rotation can be characterized from the magnitude and direction of the airflow. In other words, the magnitude and direction of airflow cause a periodic function of the torsional load with respect to the angular position of the paddle. By using Fourier analysis, it is found that the magnitude and direction of the airflow can be determined from the coefficients of the Fourier series. Typically, the torsional load of the dc servomotor, unlike the rotor speed, cannot be measured by the built-in device. In this work, it is determined by applying the extended Luenberger observer method. A state-feedback controller with the observer based on H2 control design is implemented to regulate the dc servomotor. The experimental results on the measurement of airflow show the viability of the proposed methodology.

Optimization of Fuel Two-Stage Screw Centrifugal Pump of Rocket Powerful Turbopump Unit

2018 ◽  
Author(s):  
Vasilii Zubanov ◽  
Andrei Volkov ◽  
Valeriy Matveev ◽  
Grigorii Popov ◽  
Oleg Baturin
Keyword(s):  
High Pressure ◽  
Rocket Engine ◽  
Mathematical Optimization ◽  
Low Pressure ◽  
Working Fluid ◽  
Geometrical Parameters ◽  
Rotor Speed ◽  
Optimization Software ◽  
Centrifugal Stage ◽  
Ansys Cfx

The article describes a refining method for a fuel pump of rocket powerful turbo-pump unit by the joint usage of mathematical optimization software IOSO, meshing complex NUMECA and CFD complex ANSYS CFX. The optimization software was used for automatic change of the geometry of low-pressure impeller, transition duct and high-pressure impeller to find the optimal design. It was mandatory to keep the original variant of the remaining parts of the pump. For this reason, only geometrical parameters of the blades were varied without changing the contours of the pump meridional flow part. The investigated pump consists of five parts: inlet duct, low-pressure screw centrifugal stage, transition duct, high-pressure screw centrifugal stage and volute outlet duct. The pump main parameters with water as the working fluid (based on experiment data) were the following: high-pressure stage rotor speed was 13300 rpm; low-pressure rotor speed was 3617 rpm by gearbox; inlet total pressure was 0.4 MPa; outlet mass flow was 132.6 kg/s at the nominal mode. Creation of vane unit mesh (rotors and stator transition duct) was performed using NUMECA AutoGrid5. Sector models were used for the calculation simplification. The flow around only one blade or screw was considered. Setting up and solution of the task were carried out in the ANSYS CFX solver. Comparison of calculated characteristics of the basic pump with the experimental data was performed before the optimization. The analysis of characteristics for the obtained optimized pump geometry was carried out. It was found that pump with optimized geometry has greater efficiency in comparison with the original pump variant. The obtained reserve can be used to boost the rocket engine, and/or to reduce the loading of the main turbine, which operates in aggressive oxidizing environment.

scholarly journals Changes of spin axis and rate of the asteroid (99942) Apophis during the 2029 close encounter with Earth: A constrained model

2018 ◽  
Vol 617 ◽  
pp. A74 ◽  
Author(s):  
J. Souchay ◽  
C. Lhotka ◽  
G. Heron ◽  
Y. Hervé ◽  
V. Puente ◽  
...  
Keyword(s):  
Minimum Distance ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Spin Axis ◽  
Close Encounter ◽  
Geometrical Parameters ◽  
Disturbing Potential ◽  
The Earth ◽  
Constrained Model ◽  
Angle Of Rotation

Context. The dramatic event of the 2029 close encounter between the Earth and the asteroid Apophis on April 13 2029 at a minimum distance of 38 400 km constitutes an opportunity to make investigations about the modeling of the rotational changes of the asteroid during the event. Aims. In this paper we deepen a previous study of the rotational changes of Apophis caused by gravitational effects during the close encounter, using important constraints on initial conditions brought by new recent observational data. We also evaluate the effects of the triaxial form of the asteroid on the motion of its axis of rotation in space, as well as the modifications of the spin rate due to tidal deformation. Methods. First we used more drastic constraints for the physical and geometrical parameters of Apophis, deduced from recent observational campaigns. Second we evaluated the disturbing potential due to the Earth depending not only on the asteroid flattening, but also on the component due to its triaxiality, to deduce the equations of motion and investigate the displacement of the spin axis. Third we estimated what should be the zonal deformation of the asteroid due to the tide exerted by the Earth during the close encounter and we measured the consequences on variations of the spin rate. Results. We show that the variations of obliquity and precession in longitude of Apophis during the 2029 close encounter can reach very large values, at the level of of respectiveley 1–10° and 10–40° depending on geometrical parameters. On the contrary, effects on the spin rate should be relatively small, leading to variations of the sidereal angle of rotation not exceeding 30 s. Conclusions. The tribute of this paper is to give a constrained model of the important rotational variations of Apophis during its 2029 close encounter with the Earth.

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