scholarly journals Design and Optimization of Chemical Mixing System for Vacuum Chambers: Simulation Results

2014 ◽  
Vol 5 ◽  
Author(s):  
Faruk Unker ◽  
Erdar Kaplan ◽  
Olkan Cuvalci
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Atomic Layer ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Tantalum Nitride ◽  
Ansys Fluent ◽  
Design And Optimization ◽  
Parametric Investigation ◽  
Process Gas

Computational fluid dynamics (CFD) is widely used in device design to determine gas flow patterns and turbulence levels.  CFD is also used to simulate particles and droplets, which are subjected to various forces, turbulence and wall interactions. These studies can now be performed routinely because of the availability of commercial software containing high quality turbulence and particle models. In order to understand how the gas is brought down to wafer, it is necessary to have a knowledge of the gas flow behavior very early in the design spiral of the Tantalum nitride-Atomic layer deposition(TaN-ALD) chamber by undertaking parametric investigation of the interaction effect between gas flow and the funnel structure. This paper presents such a  parametric  investigation on a generic TaN-ALD chamber using CFD. The results presented have been analyzed for a total of 11 different cases by varying neck and nozzle angles for a process gas. The gas flow was mainly investigated for the nozzle angles of  4.5◦,  9◦,  12◦  and  20◦ and the film thickness results were compared with numerical flow patterns. CFD simulations using the turbulence model in ANSYS Fluent v.13 are undertaken. The parametric study has demonstrated that CFD is a powerful tool to study the problem of gas flow-structure interaction on funnel and is capable of providing a means of visualizing the path of the gas under different operating conditions

Simulation of Rapid Thermal Processing Equipment and Processes

1993 ◽  
Vol 303 ◽  
Author(s):  
Kun-Ho Lie ◽  
Tushar P. Merchant ◽  
Klavs F. Jensen
Keyword(s):  
Heat Transfer ◽  
Thermal Processing ◽  
Gas Flow ◽  
Transient Flow ◽  
Radiation Heat Transfer ◽  
Rapid Thermal Processing ◽  
Operating Conditions ◽  
Multiple Reflections ◽  
Design And Optimization ◽  
Process Gas

ABSTRACTWe present finite element simulations of fluid flow, heat transfer, and chemical reactions in axisymmetric rapid thermal processing (RTP) configurations. A new approach to simulating radiation heat transfer between lamps, substrates, and system walls is described. The method accounts for multiple reflections and readily allows the inclusion of temperature, radiation wavelength, and materials specific emissivity parameters. The influence of system geometry, lamp power profile, substrate and wall emissivity parameters, and process gas flow upon RTP performance characteristics is illustrated through examples. Transient flow and heat transfer simulations are used to identify operating conditions where flow recirculations are avoided. The further use of physically based models in the design and optimization of RTP systems is discussed.

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

Investigation of the Flow Phenomenon Inside Gas Ejectors With Moist Gas Entrainment

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Yuping Wang ◽  
Mark Pellerin ◽  
Pravansu Mohanty ◽  
Subrata Sengupta
Keyword(s):  
Water Vapor ◽  
Phase Change ◽  
Gas Flow ◽  
Phase Distribution ◽  
Light Attenuation ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Second Phase ◽  
Symmetric Model ◽  
Design And Optimization

This paper focuses on the gas flow study of an ejector used in applications where moist gases are being entrained. Two parts of work are presented. In the first part, characteristics of gas flow inside an ejector, as well as the ejector's performance under various operating and geometric configurations, were studied with a three-dimensional computational model. Measurements were also performed for validation of the model. In the second part, focus was given to the potential condensation or desublimation phenomena that may occur inside an ejector when water vapor is included in the entrained stream. Experiments using light-attenuation method were performed to verify the presence of a second phase; then, the onset of phase change and the phase distribution were obtained numerically. A two-dimensional axis-symmetric model was developed based on the model used in the first part. User-defined functions were used to implement the phase-change criteria and particle prediction. A series of simulations were performed with various amounts of water vapor added into the entrained flow. It was found that both frost particles and water condensate could form inside the mixing tube depending on the operating conditions and water vapor concentrations. When the concentration exceeds 3% by mass, water vapor could condense throughout the mixing tube. Some preliminary results of the second phase particles formed, e.g., critical sizes and distributions, were also obtained to assist with the design and optimization of gas ejectors used in similar applications.

scholarly journals Simulation of Thermoplastic Powder Cold Spraying

2021 ◽  
Vol 14 (6) ◽  
pp. 726-734
Author(s):  
Tatyana A. Brusentseva ◽  
◽  
Vladislav S. Shikalov ◽  
Sergei M. Lavruk ◽  
Vasily M. Fomin
Keyword(s):  
Gas Flow ◽  
Experimental Studies ◽  
Cold Spraying ◽  
Deposition Efficiency ◽  
Powder Materials ◽  
Stagnation Temperature ◽  
Computational Domain ◽  
Ansys Fluent ◽  
Process Gas ◽  
Spray Method

The work is devoted to the deposition of composite powder materials by cold spray method. As a spraying material, a thermoplastic compound «WAY» for marking the roadway was used. An asphalt concrete was used as a substrate. As a result of experimental studies, the dependence of the deposition efficiency on the stagnation temperature of the working air in the ejector nozzle was obtained. The ANSYS Fluent package was used for evaluative modeling of the cold spraying process. Gas flow patterns were obtained in the computational domain without particles and taking into account the interaction of the flow with particles. The trajectory of the particles was calculated for various spraying parameters

Design of a rotor for aluminum degassing assisted by physical and mathematical modeling

MRS Advances ◽  
2017 ◽  
Vol 2 (61) ◽  
pp. 3759-3764
Author(s):  
M. Ramírez-Argáez ◽  
D. Abreú López ◽  
C. González Rivera
Keyword(s):  
Mathematical Modeling ◽  
Physical Model ◽  
First Principles ◽  
Gas Flow ◽  
Momentum Conservation ◽  
Operating Conditions ◽  
Ansys Fluent ◽  
Improved Design ◽  
Water Saturated

ABSTRACTRecent studies on aluminum degassing [1, 2] show that although the impeller speed and the gas flow rate are important process variables in terms of the productivity and operational costs, the impeller design is also a key design parameter influencing the productivity and the quality of the aluminum in foundry shops. In this work, an improved design of an impeller is tested through a water physical model and mathematical modeling and its performance is compared against commercial designs of impellers. A full-scale water physical model of a batch aluminum degassing unit was used to test the impellers by using the same operating conditions (580 rpm and 40 liters per minute) and by performing deoxidation from water by purging nitrogen into the water saturated with oxygen (similar to the dehydrogenation). A mathematical model based on first principles of mass and momentum conservation equations was developed and solved numerically in the commercial CFD code ANSYS Fluent to describe the hydrodynamics of the system with the objective of explaining the deoxidation kinetics observed in the experiments. It has been found that the new impeller design shows a better performance than the commercial designs in terms of degassing kinetics for the conditions used in this study, which is explained since the new design promotes a flow dynamics that increases the pumping effect, creating a bigger pressure drop and fluid flow patterns which help to drag and distribute more evenly the bubbles in the entire ladle than the commercial designs.

A review on empirical correlations estimating gas holdup for shear-thinning non-Newtonian fluids in bubble column systems with future perspectives

2018 ◽  
Vol 34 (6) ◽  
pp. 887-928 ◽  
Author(s):  
Ajay Sujan ◽  
Raj K. Vyas
Keyword(s):  
Rheological Properties ◽  
Gas Flow ◽  
Bubble Column ◽  
Flow Behavior ◽  
Gas Holdup ◽  
Operating Conditions ◽  
Bubble Columns ◽  
Empirical Correlations ◽  
Flow Behavior Index ◽  
Data Set

Abstract Gas holdup is one of the most important parameters for characterizing the hydrodynamics of bubble columns. Modeling and design of bubble columns require empirical correlations for precise estimation of gas holdup. Empirical correlations available for prediction of gas holdup (εG) in various non-Newtonian systems for both gas-liquid and gas-liquid-solid bubble columns have been presented in this review. Critical analysis of correlations presented by different researchers has been made considering the findings and pitfalls. As the magnitude of gas holdup depends on many factors, such as physicochemical properties of gas and/or liquid, column geometry, type and design of gas distributors, operating conditions, phase properties, and rheological properties, etc., all of these have been discussed and examined. In order to emphasize the significance, relative importance of parameters such as flow behavior index, consistency index, column diameter, gas flow rate, and density of aqueous carboxymethylcellulose (CMC) solution on gas holdup has been quantified using artificial neural network and Garson’s algorithm for an experimental data set of air-CMC solution from the literature. Besides, potential areas for research encompassing operating conditions, column geometry, physical properties, modeling and simulation, rheological properties, flow regime, etc., have been underlined, and the need for developing newer correlations for gas holdup has been outlined. The review may be useful for the modeling and design of bubble columns.

Effect of operating conditions and gas flow patterns on the system performances of IIR-SOFC fueled by methanol

2009 ◽  
Vol 34 (15) ◽  
pp. 6415-6424 ◽  
Author(s):  
P. Dokamaingam ◽  
S. Assabumrungrat ◽  
A. Soottitantawat ◽  
N. Laosiripojana
Keyword(s):  
Gas Flow ◽  
Flow Patterns ◽  
Operating Conditions

Experimental Investigations on the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals With Embedded Pressure Sensors

2020 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. Even though the non-contacting seal is proved reliable; the ultra-thin gas film can still lead to a host of potential problems due to possible contact. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB [1], the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

Modeling of Pig Assisted Production Methods

2002 ◽  
Vol 124 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Hoi C. Yeung ◽  
Paulo C. R. Lima
Keyword(s):  
Gas Flow ◽  
Transient Flow ◽  
Fluid Model ◽  
Flow Behavior ◽  
Transient Behavior ◽  
Oil And Gas Industry ◽  
Experimental Program ◽  
Finite Difference Schemes ◽  
Two Phase ◽  
Process Gas

More and more transient gas-liquid operations in pipes have been successfully applied in the oil and gas industry. Pigging operation in two-phase pipelines to remove liquid accumulation or for cleaning purpose is an important transient operation. Another important operation is the injection of gas to transport the accumulated liquid in the pipeline to process facilities. Analysis of such transient two-phase flow in a pipeline is necessary not only for designing the liquid and gas handling facilities, but also for establishing safe operating procedures. In pipeline-riser systems, such operations cause even more severe change in flow conditions. A two-fluid model has been developed to determine the transient behavior of fluids during these operations. A one-dimensional set of equations for bubble/mist, annular and stratified flows has been derived. Slug flows were modeled as a combination of the foregoing. Semi-implicit finite difference schemes were used to solve the initial and boundary value problem for each phase of the pigging process: gas/pig injection, gas shut-in, slug production, and gas flow out of the system. An extensive experimental program was carried out to acquire two-phase transient flow and pigging data on a 69-m-long, 9.9-m-high, 50-mm-dia pipeline-riser system. A computer based data acquisition system was used to obtain rapidly changing and detailed information of the flow behavior during tests. The model compared well with the experimental data for characteristics such as inlet pressure, hold-up, and pig velocity. Liquid production efficiencies for different operations were compared.

Numerical Investigation of Two Phase Flow in a Dual Drive Booster (DDB)

2019 ◽  
Author(s):  
Arun Prabhakar ◽  
Stephen Ambrose ◽  
Herve Morvan
Keyword(s):  
Power Systems ◽  
Flow Behavior ◽  
Operating Conditions ◽  
Multiphase Model ◽  
Computational Domain ◽  
Two Phase ◽  
Ansys Fluent ◽  
Oil Flow ◽  
Gear Box ◽  
Polyhedral Grid

Abstract Recent efforts have been devoted in developing cutting edge methods and technologies to overcome the complications involved in extracting power from the spools in turbofan engines to drive the power systems in aircraft. In a contemporary turbofan engine design, a Dual Drive Booster turbofan (DDBTF) summation gear box is employed to derive power from the low pressure (LP) and high pressure (HP) spools. This paper aims to investigate the scavenging of lubrication oil from the Dual Drive Booster gearbox. It is essential that that the scavenging of oil from the gearbox is efficient to eradicate risks that may arise when oil resides in the gear box for prolonged durations. Longer residence times of oil in the gearbox can lead to rapid oil degradation. Simulations were conducted on a previously optimized geometry and the work in this paper will focus on investigating the effect of different operating conditions on the scavenging performance of the scavenge chamber. The effect of attitude, altitude and the inlet flow rate of oil have been simulated to understand their influence on the oil flow behavior. Emphasis is given on the predicting potential oil churning, recirculation and pooling behaviors in the scavenge chamber that encloses the gear box. Numerical Investigations are carried out using ANSYS Fluent. The Volume of Fluid (VOF) multiphase model is employed to model the multiphase flow arising between air and oil in the system and the effects of turbulence are modelled using the standard k-ϵ model. The computational domain is discretized using a polyhedral grid comprising of 4 million cells which was adopted based on grid independency tests that were conducted prior to the main simulations. Validation against published experimental data for similar flow regimes was also carried out. Results indicate that the scavenging performance is not affected significantly under the various operating conditions and scenarios that were investigated. This is because the effects of the windage outweigh the effects caused by the different operating conditions that are imposed to the scavenge chamber. The windage in the system drives the oil efficiently out from the chamber with the aid of the tangential sump (shown in Figure 4). Oil is distributed in an axially central section of the chamber and the total residence mass of oil is compared and under 0.5 kg for all the cases presented in this paper.

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