scholarly journals Research of the fluid flow regime during the milk pipeline washing

2021 ◽  
Vol 22 (2) ◽  
pp. 278-286
Author(s):  
R. A. Mamedova
Keyword(s):  
Flow Regime ◽  
Plug Flow ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Wave Flow ◽  
Internal Diameter ◽  
Liquid Plug ◽  
Air Inlet ◽  
Opening And Closing ◽  
Degree Of Filling

The aim of the research was to determine the change in the volume of fluid slug moving in the milk pipeline for calculating the initial length of the fluid slug and thus the air slug length. This allows to control the fluid and air inlet valve during circulatory washing of milking equipment with milk line and provides a stable plug flow during washing. The article deals with the problems of formation of a wave flow and plug flow regime in a milk line in dependance to the degree of filling and shear stress on the surface of the phases. As the result, the dependence curves have been obtained. They show that when the degree of filling the milk line with liquid is from 0.4d to 0.6d, the probability of slug formation decreases. To determine the loss of a fluid slug volume moving in a milk line, mathematical calculations with the use of the boundary layer theory have been carried out. As the result, the curves of the time of fluid and air intake into the system depending on the length and diameter of the milk pipeline have been obtained. These engineering calculation methods allow to set the operating parameters of the valves for fluid and air inlet into the system during washing. To calculate the parameters of pipelines with an internal diameter of 48, 63, 70 and 98 mm often used in milking equipment, a Delphi-based program was written. The article provides an example of calculating the time of opening and closing the valve for the inlet of fluid and air during washing for a milk line with 48 mm pipe diameter, 120 m length and pressure in the system of 48 kPa. Experimental studies have confirmed the reliability of the calculations, the loss of the liquid plug length for the milk pipeline Ø50. 8 mm is on average 5 cm per 1 meter of the fluid path.

Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

2020 ◽  
pp. 17-24
Keyword(s):  
Welded Joint ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Tensile Tests ◽  
Physical Nonlinearity ◽  
Steel Plates ◽  
Optimal Parameters ◽  
Actual Problem ◽  
Numerical Research ◽  
Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

Development of an Evaporating Type Air Cooler for Ventilation Systems

2021 ◽  
pp. 37-44
Author(s):  
А. В. Бараков ◽  
В. Ю. Дубанин ◽  
Д. А. Прутских ◽  
А. А. Надеев
Keyword(s):  
Experimental Studies ◽  
Engineering Calculation ◽  
Design Calculation ◽  
Efficiency Coefficient ◽  
Empirical Relationships ◽  
Additional Energy ◽  
Air Cooler ◽  
Hot Season ◽  
Experimental And Theoretical Studies ◽  
Ventilation Systems

Постановка задачи. Подаваемый в помещения воздух в жаркое время года должен быть охлажден до комфортных температур. В связи с тем, что дополнительного расхода энергии на это охлаждение не предусмотрено, возможно применить воздухоохладитель испарительного типа. Однако известные в настоящее время результаты экспериментальных и теоретических исследований таких аппаратов не позволяют их проектировать, что препятствует их распространению. Рассмотрено строение такого аппарата и выполнены его теоретические и экспериментальные исследования, результаты которых могут быть использованы для инженерного расчета и конструирования подобных аппаратов. Результаты. Описан сконструированный авторами воздухоохладитель испарительного типа для систем вентиляции. Проведено теоретическое и экспериментальное исследование воздухоохладителя. Получены аналитические соотношения для определения времени движения насадки в «мокрой» камере аппарата, температуры охлажденного воздуха и температуры насадки в любом сечении контура циркуляции. Получены эмпирические соотношения для коэффициента эффективности охладителя и его гидравлического сопротивления. Выводы. Полученные зависимости послужат основой для разработки методики проектного расчета воздухоохладителей косвенно-испарительного типа с перемещающимся псевдоожиженным слоем в поле центробежных сил. Statement of the problem. The air supplied to the premises during the hot season must be cooled to comfortable temperatures. Due to the fact that additional energy consumption for this cooling is not provided, it is possible to use an evaporative-type air cooler. However, the currently known results of experimental and theoretical studies of such devices do not allow for their design, which prevents their spread. The structure of such an apparatus is considered and its theoretical and experimental studies are carried out, the results of which can be used for engineering calculation and design of such apparatus. Results. An evaporative-type air cooler designed by the authors for ventilation systems is described. A theoretical and experimental study of the air cooler has been carried out. Analytical relationships were obtained for determining the time of movement of the material checker in the «wet» chamber of the apparatus, the temperature of the cooled air and the temperature of the checker in any section of the circulation loop. Empirical relationships have been obtained for the efficiency coefficient of the cooler and its hydraulic resistance. Сonclusions. The obtained dependencies will serve as the basis for the development of a methodology for the design calculation of indirect-evaporative air coolers with a moving fluidized bed in the field of centrifugal forces.

scholarly journals Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

2019 ◽  
Vol 6 (7) ◽  
pp. 182061 ◽  
Author(s):  
Wuhua Li ◽  
Xiangju Cheng ◽  
Jun Xie ◽  
Zhaoli Wang ◽  
Deguang Yu
Keyword(s):  
Water Flow ◽  
Plug Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
High Water ◽  
Secondary Flows ◽  
Commercial Application ◽  
Flow Device ◽  
Intensive Aquaculture

An in-pond raceway system (IPRS) is an effective intensive aquaculture practice for regions with high water consumption and limited land resources. Water flow and dissolved oxygen (DO) are important for sustainable aquaculture. Several innovations have been made in IPRS design and operation to increase water exchange and DO concentration; one of these is the aeration plug-flow device (APFD). The APFD is commonly used in China as the only power source for water recirculation in aquaculture ponds. Understanding of the hydrodynamics of the system is necessary to improve the design of the IPRS with APFD. To this end, we performed experimental studies on a model system. We measured three-dimensional velocity at various locations using an Acoustic Doppler Velocimeter. Velocity distribution and turbulence characteristics were assessed, and plug-flow characteristics were analysed. Two patterns of velocity and turbulence in horizontal sections were observed: near the APFD, the water flow was intensively pushed downstream and simultaneously recirculated; farther away, the reflux area gradually decreased and the velocity and turbulence distribution trended towards uniform. Secondary flows occurred in different directions, which improved the diffusion of materials and DO retention. The system is effectively self-circulating, and the plug-flow capability may be scaled up for commercial application.

The jet density exponent issue for the noise of heated subsonic jets

1974 ◽  
Vol 64 (3) ◽  
pp. 611-622 ◽  
Author(s):  
R. Mani
Keyword(s):  
Speed Of Sound ◽  
Plug Flow ◽  
Experimental Studies ◽  
Acoustic Power ◽  
Point Of View ◽  
Ambient Fluid ◽  
Simple Assumption ◽  
Exit Velocity ◽  
Radiative Efficiency ◽  
Flow Round

The subject of the present study is the question of how the sound power of a jet of constant exit velocity would vary if the jet exit density were varied. Changes in jet exit density would inevitably be accompanied in a real experiment by changes in the speed of sound (temperature) in the jet, so that both effects must be considered simultaneously. The point of view advanced at the end of the study is that experimentally observed results in this area seem to admit an explanation based on how the radiative efficiency of moving acoustic sources is affected by the shrouding effect of a jet flow whose velocity, temperature and density differ from those of the ambient fluid. This change in efficiency is calculated with the aid of a simple model as follows. We determine the acoustic power output of a convected monopole source, simple harmonic in its own frame of reference, moving along the axis of a plug-flow round jet whose velocity is the same as that of the source. The jet is doubly infinite and the source is assumed to have an infinite lifetime. The density and temperature of the jet are allowed to differ from those of the ambient fluid though the specific-heat ratio of the jet fluid is assumed to be the same as that of the ambient. The requirement of equality of the static pressure inside and outside the jet then calls for a certain restraint on how the jet density and temperature vary. For a specific value of the jet exit velocity, the variation of acoustic power with the ratio of jet to ambient density along with a simple assumption on how the source strength varies with jet density are employed to deduce theoretically the ‘jet density exponent for jets which are subsonic with respect to the ambient speed of sound. The jet density exponent is found to depend both on the jet Mach number and even more strongly on a source frequency parameter. The theoretical results are compared with some experimental studies of this problem. Encouraging agreement is obtained both for the detailed observed effects on the power spectrum and the exponent for the overall power.

Flows generated by the periodic horizontal oscillations of a sphere in a linearly stratified fluid

1994 ◽  
Vol 263 ◽  
pp. 245-270 ◽  
Author(s):  
Qiang Lin ◽  
D. L. Boyer ◽  
H. J. S. Fernando
Keyword(s):  
Flow Field ◽  
Flow Regime ◽  
Numerical Models ◽  
Stokes Number ◽  
Stratified Fluid ◽  
Circular Cylinders ◽  
Wave Flow ◽  
Motion Field ◽  
Attached Flow ◽  
Internal Froude Number

The flow field induced by a sphere oscillating horizontally in a linearly stratified fluid is studied using a series of laboratory experiments. The resulting flows are shown to depend on the Stokes number β, the Keulegan–Carpenter number KC and the internal Froude number Fr. For Fr [clubs ] 0.2, it is shown that the nature of the resulting flow field is approximately independent of Fr and, based on this observation, a flow regime diagram is developed in the (β, KC)-plane. The flow regimes include: (i) fully-attached flow; (ii) attached vortices; (iii) local vortex shedding; and (iv) standing eddy pair. An internal-wave flow regime is also identified but, for such flows, the motion field is a function of Fr as well. Some quantitative measures are given to allow for future comparisons of the present results with analytical and/or numerical models. Wherever possible, the results are compared with the experiments of Tatsuno & Bearman (1990) on right circular cylinders oscillating in homogeneous fluids.

RTD Measurement, Modeling, and Analysis of Liquid Phase of Three-Tube Industrial Pulp Digester

2019 ◽  
Vol 17 (4) ◽  
Author(s):  
Meenakshi Sheoran ◽  
Avinash Chandra ◽  
Sanjeev Ahuja ◽  
Haripada Bhunia ◽  
Harish J. Pant
Keyword(s):  
Liquid Phase ◽  
Flow Regime ◽  
Residence Time ◽  
Dispersion Model ◽  
Flow Behavior ◽  
Plug Flow ◽  
Hydrodynamic Performance ◽  
Concentration Data ◽  
Tracer Concentration ◽  
Dispersion Number

Abstract Residence-time distribution (RTD) experiments were performed to analyze an industrial scale three-tube series continuous pulping digester’s hydrodynamic performance. An impulse of radiotracer 82Br (γ energy source) was introduced at the inlet of the first tube. The radiotracer concentration in the liquid phase was traced at the outlet of each tube. The input behavior of the radiotracer converted to a non-ideal pulse tracer input for the second and third tubes of the digester. Numerical convolution is adopted to deal with the non-ideal pulse input of the radiotracer. A modeling procedure for determining the RTD from the outlet tracer concentration data is proposed. A plug flow component followed by axial dispersion model is considered, and is adjusted after its convolution with the inlet tracer concentration data to obtain the RTD of the individual tubes. The obtained RTD data are analyzed to explain the flow behavior, degree of dispersion, and flow abnormalities existing in the digester. The mean residence-time (MRT), and dispersion number are estimated for the model components for the three tubes. The vessel dispersion number is found to decrease from tube 1 to tube 3. Overall, the conversion of the highly dispersed flow regime into the plug-flow regime is observed in the whole digester.

Capillary Flow of Yield-Stress Fluids in Microchannels

2006 ◽  
Author(s):  
V. Bertola
Keyword(s):  
Yield Stress ◽  
Flow Regime ◽  
Capillary Flow ◽  
Capillary Tube ◽  
Plug Flow ◽  
Wall Slip ◽  
Critical Distance ◽  
Tube Diameter ◽  
Force Balance ◽  
Theoretical Argument

The wicking of a model yield-stress fluid (hair-gel solution in water) in a capillary tube is studied experimentally. By changing the hair-gel concentration in the solution, the yield stress varied from 5 to 20 Pa. A simple force balance between capillary and viscous forces suggests that the fluid should stop flowing as soon as the wall shear stress reaches the yield value, at a critical distance from the inlet which is independent of the tube diameter. However, this theoretical argument is not confirmed by experiments, which show that the fluid moves well beyond the critical distance determined theoretically, and that there is a well-defined effect of the tube diameter. It is proposed that such behavior may be determined by wall slip, which causes the flow to switch from the Poiseuille flow regime to the plug flow regime.

scholarly journals Experimental study of liquid-liquid plug flow in a T-shaped microchannel

2016 ◽  
Vol 754 ◽  
pp. 092001 ◽  
Author(s):  
A V Kovalev ◽  
A A Yagodnitsyna ◽  
A V Bilsky
Keyword(s):  
Experimental Study ◽  
Plug Flow ◽  
Liquid Plug
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