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Determination of ejection coefficient of liquid-gas ejector with combined mixing chamber
(2023) Ponomarenko, Vitalii; Sliusenko, Andrii; Liulka, Dmytro; Yakobchuk, Roman
Introduction. The aim of the research was to develop a method for determining the actual ejection coefficient of a liquid-gas ejector with a combined mixing chamber. Theoretical calculation methods were used (balance equations of mass and energy in the form of the Bernoulli equation and the laws of hydrodynamics), experimental methods (ejection coefficients of an ejector with a combined mixing chamber were experimentally determined on a hydraulic bench in order to determine the experimental constant). The Sokolov-Zinger graph-analytical method was used to compare the ejection coefficients. Метою досліджень була розробка методики визначення фактичного коефіцієнта ежекції рідинно-газового ежектора з комбінованою камерою змішування. Використовували теоретичні методи розрахунку (рівняння балансу маси та енергії у формі рівняння Бернуллі та закони гідродинаміки), експериментальні методи (коефіцієнти ежекції ежектора з комбінованою камерою змішування експериментально визначали на гідравлічному стенді з метою визначення експериментальна константа). Для порівняння коефіцієнтів викиду використовували графоаналітичний метод Соколова-Зінгера.
Determination of the ejection coefficient of a jet apparatus with a conical-cylindrical mixing chamber
(2023) Tymchenko, Ivan; Ponomarenko, Vitalii; Lementar, Sviatoslav; Yakobchuk, Roman; Liulka, Dmytro
Ejectors have found wide application in various industries due to their simplicity, unpretentiousness to operating conditions, absence of tribological problems, etc. Their main drawback is related to the low efficiency, which is at the level of about 30%. The need to improve operational characteristics led to the creation of an innovative ejector with a combined mixing chamber (initial conical and subsequent cylindrical parts). A mathematical model based on balance equations is proposed for the possibility of determining the ejection coefficient (the main flow rate characteristic) when designing or auditing equipment
Determination of the heat transfer coefficient of a rotary film evaporator with a heating filmforming element
(2021) Zahorulko, Andrii; Zagorulko, Aleksey; Cherevko, Oleksander; Dromenko, Olena; Solomon, Alla; Yakobchuk, Roman; Bondarenko, Oksana; Nozdrina, Nataliia
A model of a rotary film evaporator with a film-forming element with a reflective heated surface has been developed. This will allow stabilizing the hydraulic movement of the cut wave flow due to the reflective surface of the geometric shape for the forced direction of the cut raw material to the heating surface. Autonomous heating of the reflective surface additionally provides a temperature effect in the conditions of movement of particles of raw materials after cutting. The analysis of the experimental and theoretical parameters of heat transfer made it possible to substantiate the criterion equation for determining the heat transfer coefficient of an evaporator with the proposed film-forming element and a reflective heated surface for calculating the coefficient from the working surface to the raw material. The resulting equation takes into account the influence of the vertical component of the motion of the raw material film, centrifugal movement during the rotation of the film-forming element, mixing of the boiling film of the raw material with steam bubbles, and the geometric characteristics of the film-forming blade on the hydrodynamic flow of the raw material. The calculation of the rotary-film evaporator was carried out using the criterion equation and the obtained useful heat exchange surface – 0.75 m2. The specific metal consumption in a rotary film evaporator with a film-forming element having a reflective surface is 57 kg/m2, compared to the vacuum evaporator traditionally used in canning industries (410 kg/m2), which is 7.1 times less. The duration of the temperature effect on the raw material is also reduced: a rotary film evaporator – 200 s and 3600 s in a traditional apparatus. The data obtained will be useful for the design of rotary-film devices of different geometric parameters using articulated blades with a reflective plate.
Improvement of drying process of beer pellet in the fluidized bed apparatus
(2014) Pohozhayev, Alexander; Yakobchuk, Roman
Introduction. It is appropriate to model and calculate the processes in the fluidized bed apparatus using computer simulation techniques and experimental studies in order to improve the drying process of beer pellet and develop new structures of dryers. Materials and methods. The process of drying spent grains in the fluidized bed dryer screw. Beer pellet has a thick consistency of rough grinding grain product, a light brown color, sweet flavor and malt smell and it rich in nutrients. Simulation of beer pellet drying was based on the finite element method using the software package Flow Vision and mathematical and statistical methods. Results and discussion. The mathematical model determining allow the coolant pressure in the drying chamber, to depend on the speed and coolant gas distribution device design and optimum conditions of drying installation. Uniform heating and drying the product in the fluidized state at any point of intersection of the drying chamber of screw dryer is achieved through high-quality distribution of coolant above gas distribution device. The expediency of Reynolds criterion definition was proved using semi-empirical interpolation formula derived by V. Goroshko, L. Rosenbaum, and O. Todes. It allows reducing of marker dimensions of the dryer. The design of screw dryers was improved by established under the perforated gas distribution grid profile that provides directional movement of coolant and coolant levels the pressure along the length of the drying chamber. Conclusions. Using the results of research for select the mode of drying in the design phase of drying equipment allows improve drying process beer pellet in the dryer.
Influence of gas-dynamic parameters of the heat carrier on the efficiency of drying peas in rotary dryers with a fluidized bed
(2020) Yakobchuk, Roman; Lementar, Sviatoslav
Introduction. The aim of the research is determination the influence of gas-dynamic parameters of heat carrier movement in the chamber of a rotary drying unit with a fluidized bed on the efficiency of the peas drying process. Materials and methods. The research was carried out on an experimental drying unit with a conical element installed in the drying chamber, and with the help of 3D models of drying units. The simulation of the heat carrier movement was performed using CFD methods, followed by verification in a pilot plant. Results and discussion. It is established that the heat carrier speed in the drying chamber without a conical element is in the recommended limits (1.8–2 m/s) only in the range from 0 to 0.7 m in the height of the chamber. The zone from 0.7 to 1.2 m is used less efficiently, because the velocity of the heat carrier is in the range of 1.65–1.8 m/s. The reason for this is that when the heat carrier passes through the wet product, its temperature decreases, it leads to decreasing of heat carrier volume. This causes the destruction of the constant mode of heat carrier and consequently reducing of the intensity of drying of the product. In the drying unit with a conical element, the stabilization of the heat carrier speed is achieved within the recommended (1.8–2 m/s) limits along the entire height of the drying zone, which provides a constant height of the fluidized bed of product in the drying chamber. This creates the conditions for a higher intensity of drying the material and improves the quality of the dried product, because it does not stay for a long time in the high temperature zone. It is found out that with heat carrier speed increasing over 2 m/s there is a decrease in the efficiency of its potential. Thus at an initial speed of 2 m/s and an initial temperature of 100 C, its final temperature is about 55 C, which coincides with drying regulations for installations of this type. While increasing speed up to 2.2 and 2.4 m/s there is final temperature increasing of the heat carrier up to 58 and 60 C and as a result it reduces the efficiency of this installation. Conclusions. This research allows to determine the influence of the installation of a conical element in the drying chamber on the speed of the of heat carrier and its pressure in the drying zone, as well as the influence of the speed of the drying agent on its temperature in this zone.
Intensification of the inverted sugar syrup production using the rotor-pulsation processing
(2021) Obodovych, Oleksandr; Shevchenko, Oleksandr; Mironchuk, Valeriy; Lymar, Valerii; Sydorenko, Vitalii; Yakobchuk, Roman
The aim of the work is to intensify the process of inverted sugar syrup production using the treatment of water-sugar solution in a rotor-pulsation apparatus. Materials and methods. The aqueous solutions of chemically pure sucrose were used. The studies were conducted using a rotor-pulsation apparatus in the range of flow shear rates from 20×103 s-1 to 50×103 s-1. Determination of carbohydrate content was carried out by high-performance liquid chromatography (HPLC). Results and discussion. The increase in temperature, processing time, and decrease in pH value at a constant flow shear rate led to an increase of the amount of inverted sugar formed. Complete inversion of sucrose occured at a treatment of sugar solution at temperature of 80 °C, pH 3.0, and a flow shear rate of 20×103 s-1 for 30 minutes. At a flow rate of 50×103 s-1 almost all sucrose was hydrolyzed at pH 3.5, and the duration of the process was just 5 minutes under conditions of five-time processing in the rotor-pulsation apparatus in the circulating mode. In the syrup prepared by the proposed technology at a temperature of 70 °C and the duration of treatment 5 minutes, all sucrose in the solution was inverted, and no traces of hydroxymethylfurfural were detected. It is assumed that critical stresses occur at the site of the sucrose chain, and the chemical covalent bonds are broken. The break of these bonds during the process of mechano-chemical destruction occurs on the weakest in terms of energy bonds. As a result of mechano-chemical influence on the section of the sucrose chain (C – O – C), there are critical stresses and the connection is broken. This leads to the formation of free radicals. One radical attaches to the OH- ion and another to the H+ ion forming glucose and fructose. Conclusions. The use of treatment of water-sugar solution in a rotor-pulsation apparatus by the proposed technology allows to intensify process of sugar inversion, namely, reduces the duration of the inversion from 120 to 5 minutes, and ensures almost complete inversion of sucrose excluding the formation of hydroxymethylfurfural.
Preconditions of the material choice and inert bodies shapes for drying of liquid foodstuff
(2013) Yaroviy, Volodymyr; Yakobchuk, Roman
Presented preconditions of the material choice and inert bodies shapes for drying of liquid foodstuff. Наведені передумови вибору матеріалу і форми інертних тіл для сушіння рідких харчових продуктів.
The influence of design parameters of rotary dryer on sunflower seeds drying
(2014) Yakobchuk, Roman
In order to improve the drying of sunflower seeds in the apparatus of the rotary type, it is appropriate to model processes in this devices using computer simulation software. Materials and methods. Simulation of sunflower seeds drying was based on the finite element method using the software package Flow Vision (company "TUSYM") and mathematical and statistical methods. Results. Mathematical models were obtained that show the dependence of pressure of coolant (air) in the drying chamber of rotary dryer on the rate of the coolant, the open cross-sectional area of the gas distributor plate and its resistance, the dependence of duration of sunflower seeds drying on fill factor of the drying chamber and its volume as well as the final material moisture content. The equilibrium distribution of the coolant pressure in the drying chamber of rotary dryer was obtained. It provides a constant height of the fluidized bed of sunflower seeds and quality of its drying. The design of rotary dryer was improved by providing the tangential supply of coolant and installing a spiral partition under gas distribution grid, which allows to uniformly distribute the coolant in the drying chamber. Conclusion. The drying process of sunflower seeds in a rotating dryer was improved. It is advisable to use the experimental result when choosing the mode of drying at the design stage of drying equipment.