Удосконалення вакуумних агрегатів на базі рідинно-парових ежекторів
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2017-01-25
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Анотація
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.14 - Холодильна, вакуумна і компресорна техніка, системи кондиціювання.
Дисертаційна робота присвячена моделюванню робочого процесу рідинно-парового ежектора (РПЕ) вакуумного агрегату, який працює по принципу струминної термокомпресії, дослідженню впливу термодинамічних параметрів і характеристик активного і пасивного потоків на процес змішування з метою отримання найбільшої ефективності агрегату.
Основним змістом дисертації є вдосконалення математичної моделі і методики розрахунку робочого процесу РПЕ для вакуумного режиму роботи, визначення діапазону початкових параметрів робочої рідини активного потоку, при яких можливе досягнення максимальної ефективності її витікання через канали, що розширюються, та закономірностей впливу початкових параметрів робочої речовини пасивного потоку на вході у приймальну камеру і геометричних параметрів камери змішування на характер змішування активного і пасивного потоків. Експериментальне дослідження РПЕ на прозорій моделі дало змогу підтвердити механізм протікання робочого процесу в області тисків нижче за атмосферний і встановити можливість досягнення максимальної ефективності шляхом оптимізації проточної частини РПЕ.
The thesis for Candidate of science degree by specialty 05.05.14 - Refrigerating, vacuum and compressor technique, air conditioning systems. Thesis is devoted the design of working process of liquid-vapor ejector (LVE) of a vacuum aggregate, working on principle of stream thermocompression, research of influence of thermodynamic parameters and descriptions of active and passive streams on the process of mixing with the purpose of achievement of most vacuum unit efficiency. The main content of the thesis is improving mathematical model and calculation method of LVE workflow for vacuum mode, which is a system of equations of conservation of mass, momentum, energy, state of the environment and the entropy production in an integrated form, and is complemented by dependencies on the kinetics of vaporization characteristics crushing and a polydisperse distribution of the liquid phase and the critical regime. The adequacy of the resulting model is confirmed by the results of experimental studies on the expiration of the expanding channel metastable superheated liquid at pressures below atmospheric and study the nature of passive mixing flows with different thermodynamic properties on the geometric parameters of the mixing chamber. The theoretical study of LVE workflow that describe the impact of the initial parameters of the active thread on the performance indicators of the working nozzle, give an idea about the use of different operating environments of the passive flow (saturated and superheated steam, steam-air mixture) and the nature of the mixing process with the change of their thermodynamic parameters. Applications received by the mathematical model for calculating the mixing chambers of various geometric shapes to evaluate the effectiveness of their use for specific conditions. Exergy analysis of LVE as apart, and then the vacuum unit as a whole, led to the conclusion of the feasibility of its use in vacuum systems in a wide range of operating parameters with a high degree of efficiency. Experimental study of LVE on a transparent model allowed to confirm the mechanism of the working process at pressures below atmospheric pressure, namely the boiling of metastable superheated liquid, characterized by the presence of three critical sections expiry of expanding the channels to the definition section of flow separation from the walls of the channel and its position relative to the nozzle exit active thread. Also investigated the nature of the mixing process in the cells of cylindrical and conical shape, allowing the possibility to establish maximum efficiency by optimizing the flow of LVE. The estimation of the appropriateness of units on the basis LVE in vacuum systems, bilge saturated steam, superheated steam and steam mixture through a comparative analysis of exergy base and schemes offered by the method of J. Tsatsaronis.
The thesis for Candidate of science degree by specialty 05.05.14 - Refrigerating, vacuum and compressor technique, air conditioning systems. Thesis is devoted the design of working process of liquid-vapor ejector (LVE) of a vacuum aggregate, working on principle of stream thermocompression, research of influence of thermodynamic parameters and descriptions of active and passive streams on the process of mixing with the purpose of achievement of most vacuum unit efficiency. The main content of the thesis is improving mathematical model and calculation method of LVE workflow for vacuum mode, which is a system of equations of conservation of mass, momentum, energy, state of the environment and the entropy production in an integrated form, and is complemented by dependencies on the kinetics of vaporization characteristics crushing and a polydisperse distribution of the liquid phase and the critical regime. The adequacy of the resulting model is confirmed by the results of experimental studies on the expiration of the expanding channel metastable superheated liquid at pressures below atmospheric and study the nature of passive mixing flows with different thermodynamic properties on the geometric parameters of the mixing chamber. The theoretical study of LVE workflow that describe the impact of the initial parameters of the active thread on the performance indicators of the working nozzle, give an idea about the use of different operating environments of the passive flow (saturated and superheated steam, steam-air mixture) and the nature of the mixing process with the change of their thermodynamic parameters. Applications received by the mathematical model for calculating the mixing chambers of various geometric shapes to evaluate the effectiveness of their use for specific conditions. Exergy analysis of LVE as apart, and then the vacuum unit as a whole, led to the conclusion of the feasibility of its use in vacuum systems in a wide range of operating parameters with a high degree of efficiency. Experimental study of LVE on a transparent model allowed to confirm the mechanism of the working process at pressures below atmospheric pressure, namely the boiling of metastable superheated liquid, characterized by the presence of three critical sections expiry of expanding the channels to the definition section of flow separation from the walls of the channel and its position relative to the nozzle exit active thread. Also investigated the nature of the mixing process in the cells of cylindrical and conical shape, allowing the possibility to establish maximum efficiency by optimizing the flow of LVE. The estimation of the appropriateness of units on the basis LVE in vacuum systems, bilge saturated steam, superheated steam and steam mixture through a comparative analysis of exergy base and schemes offered by the method of J. Tsatsaronis.
Опис
Шарапов, С. О. Удосконалення вакуумних агрегатів на базі рідинно-парових ежекторів : автореф. дис. ... канд. техн. наук : спец. 05.05.14 "Холодильна, вакуумна та компресорна техніка, системи кондиціювання" / Шарапов Сергій Олегович ; наук. кер. В. М. Арсеньєв ; Одес. нац. акад. харч. технологій, [Сумськ. держ. ун-т] . – Одеса, 2017. – 21 с.
Ключові слова
рідинно-паровий ежектор, вакуумний агрегат, струминна термокомпресія, математична модель, ефективність, жидкостно-паровой эжектор, вакуумный агрегат, струйная термокомпрессия, математическая модель, эффективность, liquid-vapor ejector, vacuum unit, stream thermocompression, mathematical model, efficiency