Numerical Simulation and Experimental Research of Oil-Free Scroll Air Compressor Based on CFD

2021 ◽  
Vol 14 ◽  
Author(s):  
Sun Jian ◽  
Peng Bin ◽  
Zhu Bingguo
Keyword(s):  
Numerical Simulation ◽  
Thermodynamic Model ◽  
Volume Flow ◽  
Working Fluid ◽  
Working Process ◽  
Scroll Compressor ◽  
Working Chamber ◽  
Actual Working ◽  
Discharge Temperature ◽  
The Law

Background: Compared with other types of compressors, although the scroll compressor has a simple structure and low noise, due to the limitation of the structure, it has defects such as excessively high discharge temperature, and has extremely high requirements on the machining accuracy of parts. The oil-free scroll compressor is a new type of scroll machine, which does not contain oil during the working process; it can be applied to cases with low displacement requirements and a high-pressure ratio. Objective: Taking a scroll compressor with a rated displacement of 0.6 as the research object, the analysis and research of the working performance parameters of the scroll compressor in actual work provide a certain theoretical basis for the improvement and optimization of the test prototype. Methods: The thermodynamic model of the scroll compressor in the actual working process is established by the variable-mass system thermodynamics and the control volume method. Based on the CFD method, a three-dimensional unsteady-state numerical simulation of the flow characteristics of the working fluid in the scroll compressor's working chamber is carried out in order to verify the thermodynamic model. Considering the accuracy of numerical simulation, a test platform with air as the working fluid is set up. Results: Through the thermodynamic model and numerical simulation, the changes of temperature, pressure and velocity in the working chamber of the scroll compressor with the orbiting angle of the main shaft as well as the gas force and torque acting on the orbiting scroll tooth are obtained. Through experiments, the law of volume flow and shaft power of the scroll compressor with the speed of change, and the law of the change of discharge temperature with pressure at different speeds are obtained. Conclusion: At the same time, the thermodynamic model established by considering heat transfer and leakage is more in line with the actual working process of the compressor; the mass exchange between adjacent working chambers of the scroll compressor has a greater impact on the temperature and pressure in the working chamber. Due to internal leakage and irreversible loss, such as heat transmission, there is a deviation between the theoretical volume flow and the actual volume flow.

Study on Mathematical Model in Working Process of Automotive Air Conditioning Scroll Compressor

2015 ◽  
Vol 741 ◽  
pp. 572-576
Author(s):  
Yu Fan Zhang ◽  
Zhi Hao Ji ◽  
Jin Yan Liu ◽  
Shu Sheng Xiong ◽  
Xiao Bo Huang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Thermodynamic Model ◽  
Air Conditioning ◽  
Mass Conservation ◽  
Back Pressure ◽  
Working Process ◽  
Scroll Compressor ◽  
Performance Simulation ◽  
Automotive Air Conditioning ◽  
Compressor Performance

In order to study the working features of automotive air conditioning scroll compressor, this paper uses mathematical model of working process to analyze it. After studying working process, a equation of suction volume is given. The thermodynamic model of compression chamber and back pressure chamber includes mass conservation and energy conservation. Based on Hydromechanics, leakage models of radial leakage and tangential leakage are discussed. The model lays a foundation of automotive air conditioning scroll compressor performance simulation.

Variable thickness scroll compressor performance analysis—Part I: Geometric and thermodynamic modeling

2016 ◽  
Vol 231 (4) ◽  
pp. 633-640 ◽  
Author(s):  
Peng Bin ◽  
Vincent Lemort ◽  
Arnaud Legros ◽  
Zhang Hongsheng ◽  
Gong Haifeng
Keyword(s):  
Thermodynamic Modeling ◽  
Variable Thickness ◽  
Geometric Modeling ◽  
Working Fluid ◽  
Base Line ◽  
Scroll Compressor ◽  
Working Chamber ◽  
Chamber Volume ◽  
Gas Heating ◽  
Compressor Performance

In order to investigate the performance of variable thickness scroll compressors, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part I, the geometric modeling and thermodynamic modeling are developed. The profile based on circle involute, high order curve, and arc is built up using the base line method. The volume of working chambers from suction to discharge is defined. Thereafter, the evolution and derivative of the working chamber volume with respect to the orbiting angle are discussed. The energy and the mass balance for working chamber are described. Suction gas heating, radial and flank leakage, heat transfer between the working fluid, scroll wraps and plates are considered in the thermodynamic modeling. The established geometric modeling and thermodynamic modeling can provide better understanding of the variable thickness scroll compressor working process. The dynamical modeling and model validation are reported in part II.

Preliminarily Design of Supercritical CO2 Compression Test System

2021 ◽  
Author(s):  
Geng Teng ◽  
Laijie Chen ◽  
Xin Shen ◽  
Hua Ouyang ◽  
Yubo Zhu ◽  
...  
Keyword(s):  
Simulation Model ◽  
Compression Test ◽  
Thermodynamic Model ◽  
Supercritical Co2 ◽  
Operating Performance ◽  
Test System ◽  
Operating Conditions ◽  
Working Fluid ◽  
Stable Operation ◽  
Test Loop

Abstract The centrifugal compressor is the core component of the supercritical carbon dioxide (SCO2) power cycle. It is essential to carry out component-level experimental research on it and test the working characteristics of the compressor and its auxiliary equipment. Building an accurate closed-loop simulation model of closed SCO2 compression loop is a necessary preparation for selecting loop key parameters and establishing system control strategy, which is also an important prerequisite for the stable operation of compressor under test parameters. In this paper, the thermodynamic model of compressor, pre-cooler, orifice plate and other components in supercritical CO2 compression test system is studied, and the simulation model of compression test system is established. Moreover, based on the system enthalpy equations and physical property model of real gas, the compressor, pre-cooler and other components in the test loop are preliminarily designed by using the thermodynamic model of components. Since the operating conditions are in the vicinity of the critical point, when the operating conditions change slightly, the physical properties of the working fluid will change significantly, which might have a greater impact on the operating performance of the system. So the operating performance and the parameter changes of key nodes in the test loop under different operating conditions are calculated, which will provide theoretical guidance for the construction of subsequent experimental loops.

Partial Admission, Axial Impulse Type Turbine Design and Partial Admission Radial Turbine Test for SCO2 Cycle

2017 ◽  
Author(s):  
Hyungki Shin ◽  
Junhyun Cho ◽  
Young-Jin Baik ◽  
Jongjae Cho ◽  
Chulwoo Roh ◽  
...  
Keyword(s):  
Axial Force ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Small Diameter ◽  
Volume Flow ◽  
Working Fluid ◽  
Rotating Speed ◽  
Turbo Generator ◽  
Partial Admission ◽  
Reduce Development Time

Power generation cycle — typically Brayton cycle — to use CO2 at supercritical state as working fluid have been researched many years because this cycle increase thermal efficiency of cycle and decrease turbomachinery size. But small turbomachinery make it difficult to develop proto type Supercritical Carbon dioxide (S-CO2) cycle equipment of lab scale size. KIER (Korea Institute of Energy Research) have been researched S-CO2 cycle since 2013. This paper is about 60kWe scale and sub-kWe class turbo generator development for applying to this S-CO2 cycle at the lab scale. A design concept of this turbo-generator is to use commercially available components so as to reduce development time and increase reliability. Major problem of SCO2 turbine is small volume flow rate and huge axial force. High density S-CO2 was referred as advantage of S-CO2 cycle because it make small turbomachinery possible. But this advantage was not valid in lab-scale cycles under 100kW because small amount volume flow rate means high rotating speed and too small diameter of turbine to manufacture it. Also, high inlet and outlet pressure make huge axial force. To solve these problem, KIER have attempt various turbines. In this paper, these attempts and results are presented and discussed.

Modification of Energy Equation for Homogeneous Cavitation Simulation With Thermodynamic Effect

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Anh Dinh Le ◽  
Junosuke Okajima ◽  
Yuka Iga
Keyword(s):  
Thermodynamic Model ◽  
Saturated Vapor ◽  
Homogeneous Model ◽  
Industrial Applications ◽  
Working Fluid ◽  
Suppression Effect ◽  
Evaporation And Condensation ◽  
Thermodynamic Effect ◽  
Cavitation Region ◽  
Cryogenic Liquids

In industrial applications, cryogenic liquids are sometimes used as the working fluid of fluid machineries. In those fluids, the thermodynamic suppression effect of cavitation, which is normally ignored in water at room temperature, becomes obvious. When evaporation occurs in the cavitation region, the heat is supplied from the surrounding liquid. Hence, the liquid temperature is decreased, and cavitation is suppressed due to the decrease in saturated vapor pressure. Therefore, the performance of the fluid machinery can be improved. Computational fluid dynamics, which involves the use of a homogeneous model coupled with a thermal transport equation, is a powerful tool for the prediction of cavitation under thermodynamic effects. In this study, a thermodynamic model for a homogeneous model is introduced. In this model, the source term related to the latent heat of phase change appears explicitly, and the degree of heat transfer rate for evaporation and condensation can be adjusted separately to suit the homogeneous model. Our simplified thermodynamic model coupled with the Merkle cavitation model was validated for cryogenic cavitation on a two-dimensional (2D) quarter hydrofoil. The results obtained during the validation showed good agreement (in both pressure and temperature profiles) with the experimental data and were better than existing numerical results obtained by other researchers.

scholarly journals Thermodynamic Aspects of Homeopathy

2020 ◽  
Author(s):  
Mihael Drofenik
Keyword(s):  
Thermodynamic Model ◽  
Healthy Person ◽  
Mass Action ◽  
Molecular Crowding ◽  
Science And Art ◽  
Healthy State ◽  
The Law ◽  
Definition Of ◽  
The Individual ◽  
Necessary And Sufficient

The well-known definition of disease, which Samuel Hahnemann presented in a tentative theory for his new science and art of healing, is used as the starting point for the thermodynamic model of homeopathy. The Le Chatelier principle was applied to the biochemical equilibrium compartmentalized in the individual human cells of an ill person to explain the curing based on the re-establishment of the starting equilibrium of a healthy person when using a remedy. It is revealed that a high dilution accompanied by succession is required to release the remedies to their constituent molecular species in order to increase their activity when taking part in the biochemical equilibrium that is essential for healing. In addition, a single remedy reaction-product species, when it is in excess, as well as satisfying the kinetic equilibrium, is a necessary and sufficient condition to force the new biochemical equilibrium in the direction of the basic original equilibrium associated with a healthy state. In addition, homeopathic aggravation is considered on the basis of the Law of Mass Action and the role of the small remedy concentration in some high-profile models is revisited. The second elementary law of homeopathy, the Law of the Infinitesimals, was explained based on a kinetic model. When a remedy occurs in the human cell of a healthy person and forms a reaction product (Simillimum) that induces the finest medical symptoms of an ill person, then remedies entering the cell of the ill person will form identical Simillimum molecules and re-establish the initial equilibrium of the healthy state and cure the ill person. However, this will also induce a molecular crowding in the cells of the ill person. For kinetic reasons, this will aggravate the re-establishment of the initial equilibrium and consequently worsen or even interrupt the medical treatment. At a low remedy concentration, the molecular crowding becomes negligible while the formation of the Simillimum and the re-establishment of the initial equilibrium will take place continuously and cure the person who is ill. The final understanding of the Simillimum in the thermodynamic model was illuminated and wide-opened its duality with the ill person’s key compound.

The Primary Discussion of Blade Sections for Application of Helium Compressor

2008 ◽  
Author(s):  
Yu E. Liu ◽  
Yufeng Sun
Keyword(s):  
Numerical Simulation ◽  
Size Range ◽  
Simulation Models ◽  
Compressor Blade ◽  
Working Fluid ◽  
Numerical Studies ◽  
Cascade Flow ◽  
Compressor Design ◽  
Inlet Conditions ◽  
Similarity Relationships

The investigation of the airfoil is a key design issue in the development and deployment of helium compressor for High Temperature Gas Cooled Reactor. As the helium physical properties are different from the air’s, three flow cases are studied to find out the similarities between helium and air using Fluent in this paper. They are flow within the divergent nozzles, flow around cylinders and flow over cascades under same inlet conditions and geometry. The results indicated some similarity relationships between helium and air cascade flow. NACA 65-(12A10)10 compressor blade was used as sample blade for both air and helium cascades. To test the performance of the blades, calculations were carried out under the condition of kinematics similitude, but different working fluid. The numerical simulation results of air cascades are correlated with NACA experiment results of air subsonic cascades very well. The numerical simulation models for the air subsonic cascades were used to test the performance of similar helium cascades. The cascade performance for helium flows were compared with the air flows and the results are presented in this paper. The purpose of numerical studies is to use blades in the current air compressor as the blades for helium compressor, to develop scaling blades in NACA 65-(12A10)10 blade size range, and to identify practical limitations to the scaling of current conventional blades. The analysis and conclusions presented in this paper can be used as a reference to helium compressor design features and the experimental research works.

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