scholarly journals Study on the process of droplet formation when liquid flows out of a capillary

2021 ◽  
Vol 939 (1) ◽  
pp. 012033
Author(s):  
A Lee ◽  
B Utepov ◽  
E Kan ◽  
O Kuychiev
Keyword(s):  
Rotation Speed ◽  
Air Flow ◽  
Rotation Frequency ◽  
Rotational Frequency ◽  
Theoretical Background ◽  
Air Velocity ◽  
Droplet Flow ◽  
Disk Rotation ◽  
Air Flow Velocity ◽  
Liquid Flows

Abstract This article presents the theoretical background for the justification of the parameters of the rotating sprayer. Theoretical studies show that an increase in the rotation frequency of the disk at a constant air flow velocity leads to a minimum median mass diameter of the droplets. Therefore, when justifying the diameter of the sprayed droplets, it is necessary to consider the combination of the disk rotation speed and the axial velocity of the air flow. To obtain high-quality air-droplet flow, the initial speed of the main droplets discharged from the periphery of the spray disc should be less than the air velocity and rotational frequency Pavlovskyi spray is recommended to be applied with in ω=60… 200 c1.

scholarly journals The investigation of the air flow distribution swirling by the rotating suction cylinder

2018 ◽  
pp. 56-60
Author(s):  
A. B. Gol'tsov ◽  
K. I. Logachev ◽  
O. A. Averkova ◽  
V. A. Tkachenko ◽  
I. V. Khodakov
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
Air Flow ◽  
Electrical Power ◽  
Flow Distribution ◽  
Rotation Frequency ◽  
Local Exhaust Ventilation ◽  
Exhaust Ventilation ◽  
Aspiration System ◽  
Air Flow Velocity

The improvement of the local exhaust ventilation consists in the emission and pollution agents' concentration at the electrical power minimum expenses. The using of the rotating exhaust cylinder in the aspiration hoods can result in the reduction of both the dust loss into the aspiration system and the dust aerosol transportation costs in the air transfer ducts. We investigated the air flow velocity distribution near the rotating exhaust cylinder depending on the rotation frequency and vented air consumption. The obtained results can be applied when the local closed exhaust hoods designing, that is the designing of the aspiration hoods with the dust-collecting chambers.

scholarly journals The Study of the Structure Based on the Array of ZnO-Nanorods as a Sensor of the Gas Flow Rate

Proceedings ◽  
2020 ◽  
Vol 42 (1) ◽  
pp. 42
Author(s):  
Victor Petrov ◽  
Alexandra Starnikova
Keyword(s):  
Sensitive Element ◽  
Gas Flow ◽  
Air Flow ◽  
Zno Nanorods ◽  
Zno Nanorod ◽  
Gas Flow Rate ◽  
Sensing Element ◽  
Air Velocity ◽  
Oxide Semiconductors ◽  
Air Flow Velocity

This work shows the possibility of using arrays of ZnO nanorods grown on a glass substrate as a sensitive element for measuring air flow velocity. Since oxide semiconductors have a temperature dependence of resistance, a theoretical and experimental assessment was made of the influence of air velocity on the increase in resistance of a sensitive element. It has been theoretically shown that when air is blown through, the temperature of the free end of the ZnO nanorod can decrease by several degrees. An experimental evaluation showed that when gas is blown at a speed of 12.5 cm/s, the resistance of the sensing element increases by about 20%, which is equivalent to a temperature increase of about 4 degrees. In addition, it was found that the dependence of the increase in the resistance of the sensitive element when exposed to an air flow from 0 to 12.5 cm / s is close to linear.

scholarly journals Calibration platform controller of the laser Doppler anemometer

2021 ◽  
Vol 2057 (1) ◽  
pp. 012092
Author(s):  
V G Glavnyi ◽  
V V Rakhmanov ◽  
S V Dvoynishnikov ◽  
S V Krotov ◽  
V G Meledin
Keyword(s):  
Rotation Speed ◽  
Laser Doppler Anemometer ◽  
Laser Doppler ◽  
Measurement Standard ◽  
Rotating Disc ◽  
Disk Rotation ◽  
Primary Measurement ◽  
Primary Measurement Standard ◽  
Air Flow Velocity ◽  
Primary Standards

Abstract Primary standards for the unit of air flow velocity often use a Laser Doppler Anemometer (LDA) as the primary measurement standard. A rotating disc with a fixed diameter is used to calibrate LDA. The paper proposes calibration platform based on the precision mechanics of HDD disk. A disk rotation controller has been developed for the platform. Deviations of the disk rotation speed do not exceed 0.01% RMS in the range of angular speeds of 600-4800 rpm.

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 Design and study of seeding devices for small selection seeding machines

2019 ◽  
Vol 126 ◽  
pp. 00008
Author(s):  
Vladimir Nemtinov ◽  
Nikolai Kryuchin ◽  
Alexandr Kryuchin ◽  
Yulia Nemtinova
Keyword(s):  
Linear Dependence ◽  
Rotation Speed ◽  
Rotation Frequency ◽  
Field Studies ◽  
Disk Rotation ◽  
Seed Supply ◽  
Computer Technologies ◽  
Laboratory Results ◽  
Agricultural Plants ◽  
Disk Rotation Speed

In this paper, it is proposed to use a self-propelled pneumatic mini-seeder with replaceable mechanical sowing devices designed and manufactured using computer technologies, advanced software and threedimensional printing for seeds selection. As a result of the research, hightech operating devices for a grain-drill feed with screw and disk-pin continuous seed metering are designed and manufactured. Grain-drill feeds allow sowing of free-flowing and non-free-flowing seeds, when used as seed meters on self-propelled pneumatic mini-seeders for selection sowing of grass seeds. Analysis of laboratory results of and field studies of the proposed grain-drill feeds allowed to determine the qualitative indicators of their performance: at a disk rotation speed of up to 15 rpm a linear dependence of the seed supply on the rotation frequency is provided; in the field studies, the instability of bluegrass seeding did not exceed 8%. The highest performance of the screw is obtained at the angle of choke inclination of 30...35 degrees with the seeding instability indicator of 2.5...3.5%. The developed grain-drill feed will significantly reduce the range of seeders and expand the set of sown seeds of various agricultural plants with one brand of a grain-drill feed.

Exploring the Polymer Drawing of the Air Centrifugal Spinning

2020 ◽  
Vol 13 (3) ◽  
pp. 189-195
Author(s):  
Jia-Jia Liu ◽  
Ting Chen ◽  
Li-Li Wu
Keyword(s):  
Flow Field ◽  
Nozzle Exit ◽  
Field Model ◽  
Rotation Speed ◽  
Air Flow ◽  
Radius Vector ◽  
Air Velocity ◽  
Centrifugal Spinning ◽  
Simulation Results

Background and Objective: The air-flow field of the air centrifugal spinning is simulated and measured. The simulated air velocities coincide well with the measured ones, confirming the correctness of the air-flow field model. Methods: The polymer drawing in the air-flow field of the air centrifugal spinning is modeled and simulated. Effects of the rotation speed and initial air velocity on the diameter and radius vector of the threadline are investigated. Results: The air velocity is found to decrease with the increase of the distance away from the nozzle exit. Simulation results show that both larger rotation speed and higher initial air velocity can reduce the threadline diameter. Conclusion: The radius vector of the threadline increases rapidly with the increase of the initial air velocity, which is helpful to reduce the threadline diameter.

scholarly journals Experimental Study on the Atomization of Plain Orifice Injector Under Uniform and Non-Uniform Cross Flowing Air Stream

1987 ◽  
Author(s):  
Yan Zhang ◽  
Jun Yong Zhu ◽  
Li Xin Wang ◽  
Ju Shan Chin
Keyword(s):  
Pressure Drop ◽  
Flow Velocity ◽  
Air Flow ◽  
Cross Flow ◽  
Orifice Diameter ◽  
Air Velocity ◽  
Air Stream ◽  
Nozzle Pressure ◽  
Large Orifice ◽  
Air Flow Velocity

The effects of three parameters: air velocity, nozzle pressure drop and injector orifice diameter, on the spray characteristics of a plain orifice injector under uniform and non-uniform cross flowing air stream have been studied experimentally. For uniform cross flowing air stream, the results show that the effects of these parameters are interrelated. The exponents of these terms in a correlation are not constants. Based on a very large amount of experimental data, the following correlation has been derived for Sauter Mean Diameter. SMD = 8.28 • 10 4 V ¯ a A • Δ P ¯ f B • d ¯ C where: A = −1.59 −0.0044ΔP̄f −0.01 d̄ B = −0.13 −0.025 d̄ +0.34 Ma C = 0.36 −0.55 Ma −0.0032ΔP̄f (Va ≤ 140 M/s ; ΔPf ≤ 11 Kg·f/cm2 ; d ≤ 2.5 mm) For small orifice diameters, the drop size distribution parameter, N (Rosin-Rammler distribution ), decreases until a minimum then increases with air velocity. For large orifice diameters, it decreases with air velocity. N always decreases with the increases of nozzle pressure drop or orifice diameter. For non-uniform cross flowing air stream, atomizations under four velocity profiles with same averaged velocity and with a velocity recess of same shape but at different radial positions have been tested. The atomization data were compared with that of uniform cross flowing air stream. Two types of comparison were made based on: a) the undisturbed velocity, b) the averaged velocity, equals to the velocity of uniform cross flowing air stream. For former situation the atomization for non-uniform cross flowing air stream tested is always poorer. The influence from the velocity recess will be maximum at certain nozzle pressure drop. The experimental evidence obtained has shown that cross flow atomization is a combination of pressure atomization (at low air flow velocity) and airblast atomization (at high air flow velocity).

scholarly journals The spraying process simulation of the low-volume sprayer working body

2021 ◽  
Vol 264 ◽  
pp. 04004
Author(s):  
Li Afanasiy ◽  
Burkhan Utepov ◽  
Satniyaz Allaniyazov
Keyword(s):  
Rotational Speed ◽  
Droplet Diameter ◽  
Air Flow ◽  
Working Fluid ◽  
Disk Radius ◽  
Droplet Flow ◽  
Radial Channel ◽  
Low Volume ◽  
Air Flow Velocity ◽  
Spraying Process

The article presents the developed mathematical models that describe the process of spraying the working body of a low-volume sprayer. Theoretical studies show that with an increase in the supply of working fluid to the atomizing disc, the rotational speed of the pneumatic disc atomizer decreases, and in order to ensure the effect of the air flow on the droplet formation process, the radius of the disc should be larger than the radius of the base of the cone-shaped fairing, but less than its maximum critical value and for obtaining a monodisperse spray with the main droplet diameter d = 80 … 120 μm, at an axial air flow velocity of the fan installation U = 40 … 60 m/s, the parameters of the disk the sprayer and the propeller are linked together when the following values: disk radius r = 65 … 85 mm, the number of radial channels on the disk nр = 2 … 6 pcs, the width of the radial channel bр = 3 … 4 mm, and to obtain a high-quality air-droplet flow, the initial velocity of the main drops discharged from the periphery of the spraying disc must be less than the speed of the air flow and, at the same time, the rotational speed of the pneumatic disc sprayer is recommended to be used in the range of ω = 60… 200 s-1.

scholarly journals The Air Flow Distribution in the Overpressure Sowing Apparatus

2020 ◽  
Vol 14 (1) ◽  
pp. 40-45
Author(s):  
A. Yu. Popov
Keyword(s):  
Flow Velocity ◽  
Flow Rate ◽  
Air Flow ◽  
Flow Distribution ◽  
Volumetric Flow Rate ◽  
Air Velocity ◽  
Air Flow Velocity ◽  
Flow Propagation

To improve the quality of the pneumatic sowing apparatus, it is necessary to study its aerodynamics. (Research purpose) Determination of air flow distribution in the upper part of the seed chamber of the sowing apparatus, taking into account the protrusions of the sowing disk, on which the quality of seeds dosing depends. (Materials and methods) The author chose a sowing apparatus operating at overpressure as an object of research. The author showed that the seed chamber constant sealing in it is provided by the protrusions of the sowing disk, which are made with cut edges on the side of the sowing disk metering element in two planes. The author applied computer simulation of the sowing apparatus. To conduct a numerical experiment, the initial and boundary conditions were determined, and the rotation of the seed disk was taken into account. The calculation of the model was carried out by changing the volumetric air flow in the range of 15-35 liters per second. (Results and discussion) The author constructed isolines of the air velocity distribution at various air flow rates. He determined the values of the air flow in the directions X, Y and Z in the sowing apparatus seed chamber. It was revealed that the largest and the smallest values of this indicator are achieved at 35 and 25 liters per second respectively. It was shown that at an air flow rate in the range of 15-25 liters per second, the distribution of the air flow in the upper part of the seed chamber would be optimal for transporting the seeds with a metering element. The air flow velocity components in Z direction vary in the range from 5.4 to 16.5 meters per second, and in the X and Y directions do not exceed 8 meters per second. (Conclusions) Based on simulation modeling, the author constructed and analyzed graphs of air flow velocity components changes in the three directions of air flow propagation. He determined the nature of the distribution of air flow in the excess seeds discharge area in the design of protrusions with cut corners. He proposed a rational range of air volumetric flow rate of 15-25 liters per second.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

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