scholarly journals Analytical studies of the technological parameters of the curved channel of the pneumatic separator

2019 ◽  
pp. 89-100
Author(s):  
S. Stepanenko
Keyword(s):  
Air Flow ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Material Particle ◽  
Fractionation Process ◽  
Basic Principles ◽  
Aerodynamic Properties ◽  
Air Speed ◽  
Trajectory Stability ◽  
Air Separator

Purpose. Establishment of the laws governing the movement of particles in the air flow with an uneven distribution of flow velocity and the action of additional forces arising from this. Methods. Theoretical studies are based on the basic principles of theoretical mechanics, in particular dynamics, as well as the theory of differential equations of the first and second order Results. A mathematical description is obtained of the movement of particles of the grain mixture in the chamber of a gravity-air separator during the action of air flows of variable speed, as well as the trajectory of particles with different sizes. With certain assumptions, the obtained patterns of change in the velocity of a material particle (point) from coordinates. Conclusions 1.Based on theoretical studies, taking into account deflecting forces, the possibility of separating particles of grain material into fractions by aerodynamic properties in vertical channels and with a lower discharge is determined. 2.The use of air flow as a separating carrier can significantly increase the value of the splitting of the trajectories and the criterion for the separation of grain into fractions. 3.Created simplified mathematical models of the movement of the components of the grain material in air separators with vertical channels, which allow us to determine the rational modes of operation of new technical means. Keywords: air flow, variable air speed, trajectory, stability of forces, fractions, fractionation process, grain mixture, air separator, pneumatic circular flow.

scholarly journals MATHEMATICAL MODELING OF PROCESSES OF SEPARATION OF COMPONENTS OF GRAIN MATERIAL IN THE COMBINED VIBRATION-AIR SEPARATOR

2020 ◽  
pp. 51-59
Author(s):  
Sergey Stepanenko ◽  
Borys Kotov
Keyword(s):  
Mathematical Modeling ◽  
Equations Of Motion ◽  
Air Flow ◽  
Flow Speed ◽  
Material Point ◽  
Experiment Planning ◽  
Theoretical Studies ◽  
Fluidized Layer ◽  
Aerodynamic Properties ◽  
Air Separator

Development of a mathematical model and calculated analytical dependencies for determining the trajectories and parameters of grain movement in a vibro-fluidized layer of grain material components under the action of a pulsating air flow. They are based on the methods of deterministic mathematical modeling and theoretical mechanics based on the equations of motion of a material point at a variable air flow speed and the action of a pulsating air flow. Theoretical studies were carried out using the methods of mathematical analysis and modeling. The research results were processed using elements of the theory of probability and mathematical statistics using software packages; to determine the rational parameters of the process, the method of statistical experiment planning was used. A mathematical description of the motion of the grain material particles in a combined vibration-air separator under the action of a pulsating air flow of variable speed is given. The trajectories of motion of particles with different sizes are obtained. The obtained equation of motion of a particle under the influence of a pulsating air flow makes it possible to determine the dependence of the speed of movement of the material in a vibro-fluidized layer of grain material on a number of factors: the geometric parameters of the sieve-free sieve, the feed angle of the material, the initial kinematic mode of the material, the index of the kinematic mode of the sieve-free sieve, as well as the coefficient of windage of the grain. On the basis of theoretical studies, the possibility of separating particles of grain material into fractions according to aerodynamic properties with vibropneumatic loading of grain into the channel has been determined. The use of a pulsating air flow as a separating carrier, and taking into account the deflecting forces, made it possible to significantly increase the splitting of the trajectories and the criterion for dividing the grain into fractions.

scholarly journals Analysis of the influence of non-uniformity of air flow velocity on the trajectory of grain particles motion in a pneumatic inertial separator

2019 ◽  
pp. 66-77
Author(s):  
B. Kotov ◽  
S. Stepanenko
Keyword(s):  
Flow Velocity ◽  
Air Flow ◽  
Kinetic Equations ◽  
Horizontal Channel ◽  
Uniform Field ◽  
Air Velocity ◽  
Aerodynamic Properties ◽  
Air Flow Velocity ◽  
Separation Of Components ◽  
Air Separator

Purpose. Determination of influence of non-uniform velocity field of air in horizontal channel of pneumatic inertial separator on efficiency of separation of components of grain material into fractions by aerodynamic properties. Methods. The specificity of the issue under consideration determines the analytical method of study based on the compilation and analysis of kinetic equations of motion of a particle, in the form of a ball in the air flow of a horizontal channel with uneven distribution of air flow velocity over the height of the pneumatic channel. Results. The mathematical description of the motion of particles of the grain mixture in the chamber of the gravitational-air separator under the action of air flow of variable speed air is given. The trajectories of motion of particles of different size were obtained. The obtained equation of motion of a particle under the action of air flow allows to determine the dependence of the speed of movement of the material in the layer of grain material on a number of factors: geometric parameters of the separator, the angle of feed of the material, the initial kinematic mode of the material, as well as the coefficient of sail of the particle. The technological possibilities of the proposed method of grain separation under the action of air flow are theoretically substantiated and the influence on the technological parameters of the basic parameters: air velocity, coefficient of live section taking into account the layer thickness of the material entering the channel is established. Conclusions 1.On the basis of the analysis of the force interaction of the grain material particle with the air stream, an advanced mathematical model of particle motion in a non-uniform field of air flow velocity in the horizontal channel was obtained. 2.The real possibility of controlling the process of separation of components of grain material by aerodynamic properties by changing the plot of the air flow velocity along the height of the horizontal channel is determined. Keywords: variable air velocity, trajectory, resistance of forces, fractions, air flow, wind factor, fractionation process, grain mixture, air separator.

scholarly journals Theoretical Studies of a Centrifugal Pneumatic Separator with Horizontal Air Flow

2021 ◽  
Vol 852 (1) ◽  
pp. 012017
Author(s):  
A V Chernyakov ◽  
V S Koval ◽  
M A Begunov ◽  
D N Algazin ◽  
K A Boytsov
Keyword(s):  
Air Flow ◽  
Theoretical Studies

scholarly journals Surface Air Movement: An Important Contributor to Ventilation of Isolated Subsurface Structures?

2019 ◽  
Vol 4 (2) ◽  
pp. 23 ◽  
Author(s):  
Thomas Neil McManus ◽  
Assed Haddad
Keyword(s):  
Air Flow ◽  
Helmholtz Resonator ◽  
Worker Safety ◽  
Time Base ◽  
Near Surface ◽  
Helmholtz Resonators ◽  
Subsurface Structures ◽  
Air Movement ◽  
Air Speed ◽  
Almost All

This study reports on near-surface airspeed measured using a fast-responding thermoanemometer during an investigation of ventilation of an isolated subsurface structure induced by natural forces. Air speed changes continuously, rapidly, and unpredictably when assessed on the time base of one or two seconds. Zero, the most common air speed, occurred in almost all tests throughout the year but especially during cool and cold months. The most probable non-zero air speed, 10.7 m/min (35 ft/min), occurred in all tests. This air speed is below the level of detection by the senses. The number of zero values and the height of the peak at 10.7 m/min follow a repetitive annual cycle. Isolated subsurface structures containing manhole covers share the characteristics of Helmholtz resonators. Grazing air flow across the opening to the exterior induces rotational air flow in the airspace of a Helmholtz resonator. Rotational flow in the airspace potentially influences the exchange of the confined atmosphere with the external one. Ventilation of the airspace occurs continuously and without cost and is potentially enhanced by the unique characteristics of the Helmholtz resonator excited by surface air movement. These results have immense importance and immediate applicability to worker safety.

A Discrete Model to Consider the Influence of the Air Flow on Blade Vibrations of an Integral Blisk Compressor Rotor

2008 ◽  
Author(s):  
Bernd Beirow ◽  
Arnold Ku¨hhorn ◽  
Sven Schrape
Keyword(s):  
Air Flow ◽  
Forced Response ◽  
Response Analysis ◽  
Element Analysis ◽  
Compressor Rotor ◽  
Aerodynamic Properties ◽  
Cascade Arrangement ◽  
Simple Mass ◽  
Mass Spring ◽  
Elastically Supported

The influence of the aerodynamic coupling in the forced response analysis of a HPC test-blisk is studied by means of a reduced order mechanical model. In the first step this equivalent blisk model (EBM) is derived based on a finite element analysis of the disk from design and an adjustment to experimentally determined blade alone frequencies in order to consider the real blade mistuning. Applying the EBM — so far not considering the air flow influence — to carry out forced response analyses due to a rotating excitation acting on the stationary blisk, a maximum blade displacement amplification of more than 50% has been calculated comparing the tuned and the mistuned blisk. Aiming at an additional consideration of the air flow, fully coupled computations of the fluid structure interaction (FSI) are exemplarily carried out for elastically supported blades in a cascade arrangement. The results are used to calibrate simple mass-spring-damper models from which quantities of additional aerodynamic elements in terms of a consideration of co-vibrating air masses, air stiffening and aerodynamic damping are derived. Based on this information the EBM is extended to a so called advanced EBM. Aerodynamic influences are considered assigning the aerodynamic properties to each blade in dependence on the inter blade phase angle (IBPA). Forced response analyses, now including all aerodynamic influences, show that for an extreme application of a rear blisk close to the combustion chamber and under MTO conditions a strong smoothing of originally localized vibration modes occurs. The maximum blade displacement amplification due to mistuning is decreased from more than 50% to below 12% for the first blade flap mode.

scholarly journals RESEARCH OF THE FUNCTIONING AND OPTIMIZATION PROCESS OF THE STRUCTURAL-TECHNOLOGICAL PARAMETERS

2020 ◽  
pp. 142-150
Author(s):  
Vitaliy Yaropud
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Thermal Power ◽  
Design Parameters ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Air Flows ◽  
Counter Current ◽  
Pipe Heat

Domestic and foreign scientists in recent years have performed a considerable amount of scientific research on the biological justification of optimal combinations of microclimate parameters required for the normal development of animals. However, the results of the studies do not allow one to specify the optimal parameters for different species of animals, taking into account their age, sex, weight and level of feeding. While it is possible to specify rather wide limits of change of temperature and relative humidity of air at which productivity is maximum, and technical and economic efficiency is approximately the same. Providing microclimate regulations in livestock premises is associated with significant costs of electricity and heat, which is about 17% of the producers' costs. To create a microclimate in livestock premises based on the above technological parameters and the analysis of the design features of the recuperators, two design and technological schemes of the three-pipe recuperator, which differ in the directions of movement of air flows, are proposed. The purpose of the research is to increase the efficiency of the technological process of functioning of the three-pipe recuperator for livestock premises by substantiating its structural and mode parameters. The results of theoretical studies of pneumatic losses in the three-pipe recuperator determined the dependence of pressure and power losses on the length of the air duct of the three-pipe recuperator, the radius of the external duct and the volume flow rate of air. As a result of theoretical studies, a mathematical model of the heat transfer process in a three-pipe heat exchanger was developed, with condensation in it, which allows to determine the temperature distribution of air flows by its length and its thermal capacity. The results of theoretical studies of the process of heat transfer in the design and technological schemes of a three-pipe recirculator with counter-current and direct-current showed that the counter-current variant is more effective. Optimization of the results of theoretical studies allowed us to determine the dependence of the design parameters of the three-pipe heat exchanger on the volumetric flow rate of air, subject to the highest useful thermal power.

scholarly journals Investigation of Grain Movement Parameters in the Liquid of the Device for Removing Ergot

2019 ◽  
pp. 248-264
Author(s):  
Vasily A Sysuev ◽  
Viktor Е. Saitov ◽  
Vyacheslav G. Farafonov ◽  
Aleksey V. Saitov
Keyword(s):  
Experimental Data ◽  
Geometric Model ◽  
Complete Separation ◽  
Winter Rye ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Linear Dimensions ◽  
Basic Law ◽  
Movement Parameters ◽  
Experimental Values

Introduction.When harvesting grain crops, various trash and harmful impurities come to the combine bunker together with grains. These harmful impurities include egot sclerotia, which are poisonous. Various modern grain cleaning machines do not provide for complete separation of ergot sclerotia from grains, because of the closeness of their linear dimensions (width, thickness and length) and speed of soaring. Cleaning seeds from ergot sclerotia having the density less than density of grain, is possible in an aqueous solution of salt. For the mechanization of the allocation of sclerotium ergot from rye seeds by a wet method, the urgent issue is the development of a device for cleaning grain material. Materials and Methods.The immersion of separately taken rye grains in water (ρzh = 1,0 ∙ 103 kg/m3) and aqueous solutions of sodium chloride (NaCl) with density ρzh = 1,09 ∙ 103 kg/m3 and 1,15 ∙ 103 kg/m3. The ellipsoid is taken as the geometric model of the grains. Theoretical studies were performed for the grain density ρz from 1,2 ∙ 103 kg/m3 to 1,5 ∙ 103 kg/m3, lengths lz from 5,0 ∙ 10–3 m to 10,0 ∙ 10–3 m, width b from 1,4 ∙ 10–3 m to 3,6 ∙ 10–3 m, and thickness δ from 1,2 ∙ 10–3 m to 3,5 ∙ 10–3 m based on the methods of mathematical modelling using the laws of hydrodynamics. For practical experiments, there was chosen the gains of the winter rye variety Falenskaya 4 having the gain density ρz from 1,1 ∙ 103 kg/m3 to 1,3 ∙ 103 kg/m3, length lz from 5,0 ∙ 10–3 m to 8,0 ∙ 10–3 m, width b from 1,4 ∙ 10–3 m to 3,6 ∙ 10–3 m, and thickness δ from 1,2 ∙ 10–3 m to 3,5 ∙ 10–3 m. Results. The speed ʋz and duration tп of grain immersion in liquids are main parameters taken into account when developing a machine for cleaning the grain material from ergot sclerotia with a wet method. The values of these quantities determine the structural and technological parameters of the machine under developing. To determine these parameters, it is necessary to take into account the geometric shapes of the grains, which have a large variety. An ellipsoid with a small 2cz = δ, an average 2bz = b and a large 2az = lz axes is proposed as the closest to the shape of the grain. From the basic law of the dynamics of the grain movement in liquids of various densities ρzh a formula was obtained for determining its velocity, the calculated values for which are consistent with the experimental data obtained. Discussion and Conclusion. It is established that the calculated values of the speed of grain immersion in liquids of different density are comparable with the experimental values of the same order. They are close and differ by no more than 10 %. This approach to determining the speed of grain immersion in a liquid can be used in developing a machine for cleaning a grain material with the wet method to substantiate its structural and technological parameters.

scholarly journals TECHNOLOGY, MEANS OF MECHANIZATION AND POWER EQUIPMENT IN AGRICULTURE

2018 ◽  
pp. 3-7 ◽  
Author(s):  
Анатолий Курочкин ◽  
Anatoli Kurochkin
Keyword(s):  
Vacuum Chamber ◽  
Raw Materials ◽  
Volume Flow Rate ◽  
Technical Solution ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Thermal Vacuum ◽  
Theoretical Substantiation ◽  
Single Screw Extruders ◽  
Vacuum Effect

The purpose of the research is theoretical substantiation of the influence of the thermal vacuum effect for the volume consumption of raw materials in the extruder with vacuum chamber. Theoretical studies of the working process of single screw extruders allowed us to obtain analytical expressions, which can be used to determine the volume flow rate of extruded raw materials serial machine. For extruders using thermal vacuum effect in their work, this theory does not allow to obtain acceptable results, since it does not take into account the fact that the technical solution implemented in the experimental extruder, compared with the serial machine allows to increase the coefficient of explosion of the extrudate in 1,5...2 times. In turn, this significantly affects the volume performance of the extruder and does not allow to determine with the necessary accuracy the structural and technological parameters of the vacuum chamber and its sluice gate. In this regard, in the carried out researches, on the basis of the equation of balance of mass of the processed raw materials which is in a path of the extruder and its vacuum chamber, the coefficient consid-ering influence of thermal vacuum effect on volume consumption of raw materials in the experimental extruder is theoretically proved, and also communication of this coefficient with other significant parameters of process of extrusion is established. The obtained results can be useful for further theoretical studies of extruders with thermal vacuum principle of operation and allow to calculate by analytical methods the main parameters of the vacuum chamber of machines performing thermoplastic extrusion of vegetable raw mate-rials.

scholarly journals Theoretical studies of the technological process of a rod elevator with an adjustable inclination angle of the apron

2020 ◽  
Vol 21 (1) ◽  
pp. 52-61
Author(s):  
A. S. Dorokhov ◽  
A. V. Sibiriev ◽  
A. G. Aksenov
Keyword(s):  
Inclination Angle ◽  
Horizontal Plane ◽  
Relative Velocity ◽  
Longitudinal Change ◽  
Theoretical Studies ◽  
Relative Speed ◽  
Technological Parameters ◽  
Average Speed ◽  
Root Crops ◽  
Maximum Separation

The article presents the design of a rod elevator with an adjustable inclination angle of the apron, which reduces damage to marketable products of root crops and bulbs with maximum separation. The results of theoretical studies of a rod elevator on substantiation of the structural and technological parameters during its interaction with a heap of onion sets are presented. The constructive-technological scheme of the separating rod elevator with an adjustable inclination angle of the apron which improves the quality indicators of harvesting onion sets is substantiated and developed. It has been established that with increasing angle of the longitudinal inclination of the apron, the relative speed of movement of the heap of onion sets decreases. In the absence of air flow, the relative velocity of the onion set heap with a longitudinal change in the inclination of the rod elevator apron in the considered range varies from 0.34 to 0.47 m / s. Changing the angle of the longitudinal inclination of the rod elevator by 5º significantly changes the relative average speed of movement of the heap of onion sets. A mathematical model of the movement of a heap of onion sets along the surface of the rod elevator with a change in the direction of its oscillations in the horizontal plane is developed

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