Specific Flow Rate Research Articles

A detailed investigation of an evacuated flat plate solar collector

The evacuated flat plate collector is a pioneering solar device for operation at medium temperatures (<200 °C) with high efficiency and without the need for tracking. The goal of this investigation lies in the detailed parametric analysis of an efficient evacuated flat plate collector and its daily performance for the city of Athens (Greece). The parametric analysis presents the instantaneous thermal and exergy performance of the collector for different inlet temperatures, solar irradiation levels, ambient temperatures, specific mass flow rates and the number of riser tubes. The daily analysis presents results for the thermal and exergy performance of the collector for different daily profiles of solar irradiation and ambient temperatures using real weather data. Also, the main innovation of this study lies in the development of a correlation of the daily useful output by taking into account the operating temperature level, the daily irradiation level and the mean ambient temperature. According to the yearly analysis, the optimum exergy efficiency is found at 13.33% for operation at 125 °C and the respective thermal efficiency is found at 47.24%. For this case, the levelized cost of energy and exergy were calculated at 0.0274 €/kWh and 0.1043 €/kWh respectively.

Optimizing the parameters of the air disc atomizer for the low volume desalination spraying of cotton crops

The article presents the results of a multi-factorial experiment to justify the parameters of a rotating sprayer. Optimization of the parameters of the pneumatic disk atomizer shows that with the correct choice of the specific liquid flow rate (qi), disk radius (r) and the number of radial channels (η r) at a constant air flow rate, it leads to obtaining the required median-mass droplet diameter. Therefore, when justifying the diameter of sprayed drops, it is necessary to consider a combination of the specific flow rate of the liquid and the radius of the disk. To obtain a monodisperse spray of drops with a median-mass diameter d= 80…120 µm, the disc radius should be in the aisles r=75.8…83.4 mm, the specific liquid flow rate qi= 0.61…0.96 l/min and the number of radial channels for pairs of disks in the aisles η p = 4.59… 5.75 things.

Applications of Machine Learning Methods to Predict Hole Cleaning in Horizontal and Highly Deviated Wells

Summary Machine learning (ML) has become a robust method for modeling field operations based on measurements. For example, wellbore cleanout is a critical operation that needs to be optimized to enhance the removal of solids to reduce problems associated with poor hole cleaning. However, as wellbore geometry becomes more complicated, predicting the cleaning performance of fluids becomes more challenging. As a result, optimization is often difficult. Therefore, this research focuses on developing a data-driven model for predicting hole cleaning in deviated wells to optimize drilling performance. More than 500 flow loop measurements from eight studies are used to formulate a suitable ML model to forecast hole cleanout in directional wells. Measurements were obtained from hole-cleaning experiments that were conducted using different loop configurations. Experiments ranged in test-section length from 22 to 100 ft, in hole diameter from 4 to 8 in., and in pipe diameter from 2 to 4.5 in. The experiments provided measured equilibrium bed height at a specific flow rate for various fluids, including water-based and synthetic-based fluids and fluids containing fibers. Several relevant test parameters, including fluid and cutting properties, well inclination, and drillstring rotation speed (drillpipe rev/min), were also considered in the analysis. The collected data have been analyzed using the Cross-Industry Standard Process for Data Mining. This paper is unique because it systematically evaluates various ML models for their ability to describe hole cleanout processes. Six different ML techniques: boosted decision tree (BDT), random forest (RF), linear regression, multivariate adaptive regression spline (MARS), neural networks, and support vector machine (SVM) have been evaluated to select the most appropriate method for predicting bed thickness in a wellbore. Also, we compared the predictions of the selected ML method with those of a mechanistic model for cases without drillstring rotation. Finally, using the ML model, a parametric study has been conducted to examine the impact of various parameters on the cleanout performance of selected fluids. The results show the relative influence of different variables on the prediction of cuttings bed. Accordingly, flow rate, drillpipe rev/min, and fluid behavior index have a strong impact on dimensionless bed thickness, while other parameters such as fluid consistency index, solids density and diameter, fiber concentration, and well inclination angle have a moderate effect. The BDT algorithm has provided the most accurate prediction with an R2 of 92%, a root-mean-square error (RMSE) of 0.06, and a mean absolute error (MAE) of roughly 0.05. A comparison between a mechanistic model and the selected ML technique shows that the ML model provided better predictions.

A comparative study on pedestrian flow through bottlenecks between flood evacuation and land evacuation

In a flood, people may be forced to evacuate in water until reaching a secure shelter. Understanding the characteristics of pedestrian flow in water is therefore of utmost importance. Some researchers studied individual walking speed in water, whereas it is still rare to study pedestrian and evacuation dynamics, e.g., characteristics of pedestrian flow through a bottleneck. In this paper, evacuation experiments through bottlenecks are conducted in 0.60-m-deep water, with 97 volunteers with an average age of 21.7 years participating. The results are compared with those on land. It is shown that the flow rate in water is lower than that on land, with a difference varying with bottleneck width b as ΔJ=0.60b−0.04ped/s. The average specific flow rate in water is 0.43ped/(m·s) lower than that on land. Based on the relation of time headway–width, density–width, and speed–width, threshold widths for the flow transition from “interrupted” to “flowing” stages are 1.3 m in water and 1.0 m on land respectively. Compared with that on land, during “interrupted” stage in water, stop behavior is more frequent, the speed near the exit is 0.22 m/s lower, and the speed-up point is closer to the exit. During “flowing” stage, continuity of the pedestrian flow at exit is inferior in water compared to that on land, a 0.2–0.3 m wider exit is required in water to achieve similar continuity on land. These findings may provide valuable insights into emergency management during flood evacuation.

Experimental and Numerical Analysis of a Pd-Ag Membrane Unit for Hydrogen Isotope Recovery in a Solid Blanket.

The interest of the fusion community in Pd-Ag membranes has grown in the last decades due to the high value of hydrogen permeability and the possibility of continuous operation, making it a promising technology when a gaseous stream of hydrogen isotopes must be recovered and separated from other impurities. This is the case of the Tritium Conditioning System (TCS) of the European fusion power plant demonstrator, called DEMO. This paper presents an experimental and numerical activity aimed at (i) assessing the Pd-Ag permeator performance under TCS-relevant conditions, (ii) validating a numerical tool for scale-up purposes, and (iii) carrying out a preliminary design of a TCS based on Pd-Ag membranes. Experiments were performed by feeding the membrane with a He-H2 gas mixture in a specific feed flow rate ranging from 85.4 to 427.2 mol h-1 m-2. A satisfactory agreement between experiments and simulations was obtained over a wide range of compositions, showing a root mean squared relative error of 2.3%. The experiments also recognized the Pd-Ag permeator as a promising technology for the DEMO TCS under the identified conditions. The scale-up procedure ended with a preliminary sizing of the system, relying on multi-tube permeators with an overall number ranging between 150 and 80 membranes in lengths of 500 and 1000 mm each.

Experimental Investigation of Centrifugal Pump Characteristics

The pumps are divided into two main groups as positive displacement namely volumetric pumps and dynamic i.e. centrifugal pumps. Volumetric pumps are generally used to transport hydraulic oils, while centrifugal pumps are used to transport clean or dirty water. Pumps are the tools that are used to move liquid fluids from one place to another in many areas like as cars, industry, construction sites, agriculture, and homes. Therefore, determination of the hydraulic pump’s characteristics under various working conditions, including manometric head, overall efficiency, specific speed, and net positive suction head, is crucial for development, operational limitations, and durability. Experimental investigation is a more realistic method, although it is possible to determine the hydraulic pump characteristics by means of mathematical methods. Therefore, an experimental investigation is performed for the determination of the centrifugal pump characteristics in this study by using an experimental setup. The findings indicate that the hydraulic power given to the water and the electrical power used by the pump both increase up to a particular flow rate and then decline. Additionally, it is found that manometric head of the pump falls even as the overall flow losses rise as the flow rate rises. On the other hand, overall efficiency of the pump enhances at the specific flow rate and then it reduces with the increased flow rate while specific speed of the pump varies about linearly. Moreover, it is finally noticed that the tested centrifugal pump works in cavitations at all flow rates.

Analyzing the S-characteristic of pump-turbine under the same head condition from the perspective of flow energy dissipation

The S region on the full characteristic curve of pump-turbine is one of the important key features that affect its operation stability. In S region, one specific rotational speed value ( n11) corresponds to three specific flow rate values ( Q11), which causes the unit to fluctuate between different operation conditions. In this paper, focusing on the special region of pump-turbine, based on the combination of model experiment and numerical simulation, the S-region dynamic model of pump-turbine is established. The internal flow mechanism of pump-turbine is analyzed in detail from the perspective of Flow Energy Dissipation (FED). The results show that the high FED component is different at different operating points, but the flow energy maintain balance in the pump-turbine unit. High FED area displayed in near-wall or inter-channel of different components under different flow conditions. Besides, the generation of S region is related to the dynamic balance of energy especially in the no-load region. The analysis results of this paper provide theoretical basis for scientific and stable operation of pump-turbine.

131 An Alternative Method for Measuring Sample Pump Pulsation

Abstract Sampling pumps are an essential part of the chemical exposure assessment process, as the flowrate is used for the calculation of the atmospheric concentration of pollutants. Flowrate stability is important for its contribution to uncertainty, but also because some of sample trains require a specific flow rate value to properly operate, especially for particle sampling. Pump principles are based on rotary or alternative movements which involves a very short variation in flowrate, called “pulsation”, which lasts few milliseconds and is not perceptible with a conventional flowmeter. This pulsation is a critical parameter to be measured for the characterization of the pump. The international standard ISO 13137 specifies the method for evaluating the pulsation which is based on the use of a rapidly responding hotwire anemometer. This method is particularly precise and sensitive but complex to set up and calibrate. We have developed an alternative method for measuring pump pulsation based on the determination of acoustic pressure. Assuming that the sample pumps connected to a solid tube are plane wave generators with infinite impedance, the acoustic pressure measurement is the sum of the incident and reflected waves. Using five microphones in the the acoustic pressure can be measured in the tube to calculate the acoustic velocity and therefore the dynamic flow with a very high frequency. 13 different individual pumps were tested with both hotwire anemometry and acoustic pressure methods. Pulsation result comparison with both methods exhibits a great agreement. Acoustic pressure measurement is therefore a very convenient alternative method for the personal pump pulsation determination.

SELECTION OF COMPLEX ACTION SOLUTION AND JUSTIFICATION OF ITS SPECIFIC CONSUMPTION FOR MOISTENING OF BLASTED SULFIDE ORE PILES PRONE TO SPONTANEOUS COMBUSTION

At mining of minerals by an open-cut method with the use of highly productive mining equipment the contamination of the environment by dust emitted during various mining works takes place. Especially, at excavation of rock mass without application of means of dust suppression, the most intensive dust emission is observed. The main way to reduce dust emission is to wet the rock mass. However, the fight against dust is complicated during the development of sulfide ores prone to spontaneous combustion. The matter is that water may intensify the process of oxidation and self-heating of sulfide ores in the pile. In this connection in such conditions the traditional method of hydro-dusting cannot be used as it takes place in open pits, mined out in normal mining and geological conditions. Therefore, when developing sulfide ores prone to spontaneous combustion, for dampening it is recommended to use solutions having along with the effectiveness of dedusting and antioxidant properties, i.e. complex action. The expression for determining the specific flow rate of fluid (q), necessary to reduce dustiness to MPC is proposed. The equation for determining the moisture content of the rock mass at a depth corresponding to a certain point in time is proposed. The solution of this equation has allowed to receive the formula, allowing at known values of parameters of height of humidified heap H, m; maximum humidity of ore φm, %; natural humidity φ_e %; volume weight, kg/m3, characterized by relative constancy for the specific conditions of the pit, to determine approximately the specific consumption of the solution for its penetration to the center of self-ignition, depending on the change in the depth of the center. For practical use the highest calculated value of the specific flow rate of the solution, providing the reduction of air dustiness to MPC and the penetration of the solution to the center of self-heating, is taken.

Rationale for alternative water sources for mining regions with high environmental footprint on the example of Levikha village of the Sverdlovsk region

Introduction. Mine drainage has always been one of the main threats to the hydrosphere of mining areas, both during and after active mining. The most common method of mine water neutralization is associated with the slaked lime. On the abandoned Levikha copper-sulphide mine territory (Sverdlovsk region), acid mine drainage discharge reaches 3,000 m³/day. To neutralize acid waters, more than 400 m³/day of water with a neutral pH is required (to produce the slaked lime). Due to the worn out state of water pipe from the river Tagil, heavy losses, and frequent accidents, the neutralization station receives no more than half of the required amount of water. As a result, the neutralization technology is violated, acid mine drainage is not properly cleaned, the regulatory requirements for wastewater are not achieved, and sulfate waters with increased mineralization and metal concentrations are discharged into the river Tagil. Research objective is to substantiate the possibility of finding sources of drinking, household and process water supply for Levikha village and acid mine drainage neutralization stations by applying groundwater. Methods of research include a comprehensive approach containing research results analysis and field and laboratory research data processing. Results and discussion. Promising areas have been identified representing private catchment areas of potential water intakes with the most favorable conditions for underground runoff. A combination of the following factors was the criterion for promising areas and load points: favorable geological and tectonic conditions (the presence of tectonic faults); groundwater inflow testing results (relatively high specific flow rates of wells); geomorphological position (confinement to low relief areas, location near surface sources of groundwater recharge); hydrochemical sampling data (satisfactory chemical composition of groundwater); sanitary and hygienic situation (absence of potential sources of pollution in the local catchment area). Conclusions. The total resources of the five promising sites are 1,340 m3 /day, including 282 m3 /day for drinking purposes. Exploration and development of promising areas no. II (favorable geological and tectonic conditions within it are confirmed by the groundwater inflow testing results) and no. III (favorable sanitary and hygienic conditions) seem to be the most reasonable. These sites might cover half of the village water needs for drinking and household purposes.

Analysis of the main factors determining the value of the specific flow rate of a water well

Purpose of research – numerical characterization of the main factors affecting the value of the specific flow rate of a water well. The relevance of the study is due to the possibility of using the obtained functional relationships to predict the value of the specific flow rate of a water well. Research methods: interpretation of gamma logging curves of water wells, correlation of its results with the core survey data, interpolation of the obtained values over the section area, processing of hydrodynamic well testing materials, comparison of its results with the data of geophysical research, establishment of statistical relationships between the parameters. The results of the study and their application. It was found that the value of the double difference parameter of natural radioactivity of water-bearing rocks statistically significantly correlated with the value of the clay content of core samples, studied in the laboratory way, as well as with the value of water permeability of rocks determined by hydrodynamic tests wells, which allows using this parameter to characterize the filtration properties of rocks aquifer by the value of their clay content. Significant statistical relationship was obtained between the specific flow rate of the water intake well and water conductivity of water-bearing rocks, the parameter of imperfection of the well by the nature of the formation opening, as well as the parameter, numerically equal to the ratio of the well filter length to the value of the double difference parameter of natural radioactivity of rocks of its installation interval. The presence of statistical uncertainty in the relationships is due to the mutual influence of the parameters. The obtained functional relations can be used in the design of wells. Conclusions. During the study the assumption was confirmed that water intake wells with the longest water intake part, equipped in the least clayey and, accordingly, more water-permeable interval of aquifer have the least value of imperfection by nature of formation opening and are able to provide the highest specific flow rate. Such wells are the most effective in operation.

Optimization-Based Selection of Hydrants and Valves Control in Water Distribution Networks for Fire Incidents Management

In England and Wales, water utilities reduce hydraulic pressure to a minimum regulatory threshold in order to reduce leakage and avoid financial penalties. However, utilities are not legally bound to guarantee specific flow rates from fire hydrants, thus posing a risk for firefighting. We formulate a biobjective mixed-integer nonlinear program (MINLP) to simultaneously determine control valve settings and the location of fire hydrants to be utilized in a water distribution network during urban fire incidents. The goal is to provide the required flow rate from the fire hydrants while minimizing 1) the distance of the utilized fire hydrants from the fire location and 2) the impact on customer supply. As the solution is required in real-time, we propose an optimization-based heuristic, which relies on iteratively solving a NLP approximation and relaxation of the MINLP formulation. Furthermore, we assess the quality of the heuristic solutions for the presented study case by calculating global optimality bounds. The proposed heuristic is applied to an operational water distribution network.

Moisture content distribution model for the soil wetting body under moistube irrigation

This study investigated the moisture distribution characteristics of a soil wetting body under different influencing factors to inform the design and management of a moistube irrigation system. A mathematical model of soil moisture movement under moistube irrigation was established based on Hydrus-2D software. The suitability of the Hydrus-2D simulation model was verified by laboratory experiments. Numerical simulations were carried out with Hydrus-2D to investigate the influence of soil texture, initial moisture content, moistube specific discharge and irrigation time on the moisture distribution of a soil wetting body. The soil moisture content is highest at the moistube, and its value is related to the moistube-specific discharge and soil texture. The soil moisture content at any point in the wetting body decreased linearly with increasing distance from the wetting front to the moistube in the five set directions (vertical downward, 45° downward, horizontal, 45° upward and vertical upward). This trend is applicable to fine-textured and coarse-textured soil. An estimation model of soil moisture content including soil saturated hydraulic conductivity, initial soil moisture, the specific flow rate of the moistube and the maximum value of the wetting front distance in all directions is proposed. The model estimation is good (root mean square error = 0.008–0.018 cm3·cm−3, close to 0; Nash-Sutcliffe efficiency coefficient = 0.987, close to 1), and it can provide a practical tool for moistube irrigation design and agricultural water management.

Performance prediction of random variable-width microfluidic chips by convolutional neural networks

With the development of personalized healthcare, tailor-made medications are receiving increasing attention. Solutions of specific concentrations or flow rates need to be acquired before medication can be manufactured. To efficiently and accurately generate solutions with specific concentrations or flow rates, we proposed the design of random variable-width (RVW) microfluidic chips, which perform significantly outperform random equal-width (REW) microfluidic chips, and predict their performance through Convolutional Neural Networks (CNN). First, we proposed the design of RVW microfluidic chips to extend the range of concentrations and flow rates. Second, the KD-MiniVGGNet model was designed, which effectively improved the accuracy of predicting the outlet concentrations and flow rates of the RVW microfluidic chips. Finally, a database of 51 032 RVW microfluidic chips was built by the KD-MiniVGGNet, which provided a sufficient number of candidate designs. The results showed that the RVW microfluidic chip could provide broader and better candidate designs, and the prediction accuracy of the outlet fluid behavior could be increased to 93%.

INFILTRATION AND COLMATATION DYNAMICS ON PHYSICAL MODELS STUDY BY INFILTRATION BASINS AT ARTIFICIAL GROUNDWATER RECHARGE

The problem of the growing shortage of water resources in the world, including in the territory of South-East Kazakhstan, due to global warming and aggravated by long distances to natural sources of good quality water, requires the combined use of surface water and groundwater from local aquifers to supply the local population with high-quality drinking water. The application of methods of artificial groundwater spreading can be an effective way only if positive characteristics of soil and soil parameters of the aeration zone and productive aquifers are obtained in the processes of infiltration and colmatation, which are one of the decisive indicators for ensuring productivity and duration of operation of infiltration basins in the given mode. This work presents the main results of complex field studies of the processes of infiltration and colmatation in infiltration mini-basins at pilot sites within the Aksu, Lepsy and Koksu river valleys, taken as typical for the territory of South-Eastern Kazakhstan, which most needs to increase the water supply of rural population settlements and remote pastures. These studies were supplemented by a detailed assessment of the water-physical, hydrodynamic and filtration properties of the overburden and the upper layers of the aquifer. The new data showed that the infiltration rate varied from 15 m/day at the beginning to 0.75 m/day at the end and remained practically unchanged by the end of the experiment. This was largely facilitated by the values of the heterogeneity coefficient of the granulometric composition of all the examined soils obtained during the studies, which did not exceed 3.0 due to the uniform distribution of coarse fractions and a small proportion of loams and sandy loams. Approximately one month after the start of the tests, a colmatation layer began to be generated at the bottom of the mini-ponds, the thickness of which by the end of the test reached from 3 mm for clay silt to 6 mm for silty clay. However, as studies have shown, the generation of a colmatation layer due to the settling of suspended particles of surface water did not significantly impact on the infiltration processes, as evidenced by the rated values of specific flow rates, which in the final period of time ranged from 0.86 to 0.75-0.80 m3/day per square meter of reduced infiltration surface. Thus, the generated positive results of field studies can serve as a factual basis for design, and can also be recommended and accepted as design indicators both at the stage of a feasibility study and at the stage of detailed design of artificial groundwater spreading systems without additional labor-intensive and costly survey works, and the approved methodology for their implementation will be useful when conducting similar studies in other regions.

Исследование фильтрации из оросительного канала методом электрогидродинамических аналогий

Purpose: simulation of the filtration process from an irrigation canal made in an earthen channel. Materials and methods. One of the most common methods in the waterworks construction and operation is the filtration process modeling. In practice, the use of mathematical modeling based on the use of mathematical analogies of various physical processes, which are described by the same differential equations, is widespread. The electric analogy method (EGDA) is based on the analogy between the groundwater velocity and the electrical current flow and allows solving various filtration problems on models of electrically conductive materials. The purpose of modeling the groundwater velocity using the EGDA method is to develop a model similar to a full-scale object, for studying the ongoing filtration processes with its help. Results. A flow net and a filtration velocity profile which were used to study free filtration from a canal in an earthen channel were constructed. As a result of the study, the specific filtration flow rate, filtration rate were determined and a comparison with the values obtained by calculation was made. Comparison of the results obtained from the flow net with the calculation formula showed that their values coincide with an error of 1.26 %. The specific flow rate determined by the calculation method coincides with the flow net value for the selected belt of equal pressure with an error of 2.8 %. Conclusions: the EGDA method allows determine effectively the seepage water losses from the canal, however, when quantifying the seepage flow, it gives more significant errors due to the complexity of complete recording when modeling the real conditions of the object under consideration.

Numerical study of pressure profiles in an annular combustor and a manifold during continuous spin detonation of nonstoichiometric hydrogen-air mixtures

A closed mathematical model of continuous spin detonation of nonstoichiometric hydrogen-air mixtures in a quasi-three-dimensional unsteady gas-dynamic formulation taking into account the reverse effect of the oscillation processes in the combustor on the mixture injection system is utilized in pressure profiles in the combustion chamber and in the manifold investigation. Numerical simulations are performed for the flow-type annular combustor 503 mm in diameter with an annular gap of width 18 mm and other geometric dimensions corresponding to experiments. Three-wave mode of continuous spin detonation is calculated and the flow structure is analyzed for the equivalence ratio of 0.6 and the specific hydrogen-air mixture flow rate of 390.6 kg/(s·m2). The static, the mean static and the mean total pressure distributions in the combustor are calculated. The results are validated against experimental data.

Substantiation of actual and forecast reclamation situation in assessing effectiveness of artificial drainage in irrigated areas in management of water resources

In the context of this work, when evaluating the effectiveness of artificial drains on irrigated lands in modern conditions, irrigation networks, reclamation regime, irrigation, salt washing, drainage, agricultural technology (not considered here), and land use in a specific composition and high flow rates, as well as one-dimensional differential equations that provide the necessary water-salt regimes by substantiating the actual and predicted reclamation state using the WASTER computer program. The amount of drainage is taken from the methodology of the water-salt balance of the Research Institute of Irrigation and Water Problems (RIIWP) and is set in the WASTER computer program. For example, artificial drainage was used on irrigated lands in the Pakhtakor district of the Jizzakh region. Irrigation regimes and rates are considered in 2 variants, considering drainage in the WASTER computer program for these areas. These models take into account the absorption of moisture and salts from the soil into the root layer of the plant, taking into account the work of artificial drainage in boundary conditions. The calculated criteria for each option are compared and analyzed. In addition, the volumetric moisture content and salinity are observed and analyzed in the layers. In addition, we considered the experiments and methods carried out by other scientists.

Experimental study on the stability and breakup of a planar liquid sheet under a standing wave acoustic field

With experiments and theory the effect of acoustic parameters on the stability and break up of a planar liquid sheet under the influence of a standing acoustic wave are studied. Atomization characteristics of slit nozzles and the effects of acoustic pressure and injector position are analyzed. Above a critical acoustic pressure the standing wave acoustic field generates a Faraday wave on the liquid sheet surface. At a specific flow rate an empirical coefficient is found which enables linear instability theory to predict the wavelength of the Faraday waves and the breakup length of the liquid sheet.

IMPROVEMENT OF CONTACT DEVICES OF THE BUBBLING TRAY

The results of a study of hydrodynamics and mass transfer on bubbling-type trays with valve, valve-vortex and vortex contact devices are presented. By means of experimental studies and numerical modeling, the velocity fields of liquid and gas, as well as the structure of the gas-liquid layer on the tray are determined. The dependence of the relative amplitude of fluctuations in the level of the gas-liquid layer on the tray by the gas flow rate when placing various types of contact devices on it is obtained. The average surface diameter of gas bubbles is determined and the mechanism of their accumulation in the liquid on the tray is proposed. The relationship between the velocity of liquid circulation on the plate and the size of gas bubbles entrained by the circulation flow has been confirmed. The pressure drop of the investigated contact devices was measured and the value of the hydraulic resistance coefficient was determined. Experimental data on the intensity of mass transfer and efficiency on tray are presented. Specific fluid flow rates have been established to ensure high efficiency.It is shown that the most efficient, liquid- and gas-carrying capacity is possessed by trays with vortex cantate devices having a low amplitude of oscillation of the gas-liquid layer and a large interfacial surface. This is due to an increase in the energy dissipation of gas jets in the liquid on the tray, the uniform distribution of gas bubbles and the presence of rotational motion of the gas-liquid layer.