scholarly journals Numerical simulation of the oxygen distribution in silicon melt for different argon gas flow rates during Czochralski silicon crystal growth process

2018 ◽  
Vol 204 ◽  
pp. 05013
Author(s):  
Zumrotul Ida ◽  
Jyh-Chen Chen ◽  
Thi Hoai Thu Nguyen
Keyword(s):  
Flow Pattern ◽  
Oxygen Concentration ◽  
Flow Rate ◽  
Growth Process ◽  
Gas Flow ◽  
Silicon Crystal ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Argon Gas ◽  
Flow Motion

The effects of argon gas flow rate on the oxygen concentration in Czochralski (CZ) grown silicon crystal were examined. To analyze the influence of the argon gas flow rate in CZ growth process, a 200 mm length silicon single crystal was grown. Different argon gas flow rates are considered. The melt flow pattern, temperature and oxygen concentration distributions in the melt and crystal-melt interface are calculated. The results show that the transport of oxygen impurity is quite dependent on the flow motion in the melt. As the argon gas flow rate increases, there is no fundamental change in flow motion of the melt and the oxygen concentration decreases to a minimum value. When the argon gas flow rate increases further, the flow pattern under the melt-crystal interface starting changes and the oxygen concentration has increased after. Therefore, there is an optimum value for the argon gas flow rate for obtaining the lowest oxygen concentration in the melt.

scholarly journals Flow Field in Slab Continuous Casting Mold with Large Width Optimized with High Temperature Quantitative Measurement and Numerical Calculation

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 261
Author(s):  
Chao Ma ◽  
Wen-yuan He ◽  
Huan-shan Qiao ◽  
Chang-liang Zhao ◽  
Yi-bo Liu ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Flow Rate ◽  
Casting Speed ◽  
Gas Flow ◽  
Immersion Depth ◽  
Mold Surface ◽  
Gas Flow Rate ◽  
Argon Gas ◽  
Slag Entrainment

In this paper, the rod deflection method was applied to quantitatively measure velocity near the mold surface at high temperatures and the k-ε model coupled with a discrete phase model (DPM) was adopted to simulate the flow field in the mold. The calculated results match very well with the measured results under all the present conditions. Under the conditions of the large mold width of 1800 mm, 1.1 m/min casting speed and 140 mm submerged entry nozzle (SEN) immersion depth, the velocity near the mold surface decreases with increasing the argon gas flow rate. When the argon gas flow rate is 6 L/min, the flow pattern is the double roll flow (DRF). When the argon gas flow rate is increased to 10 L/min and 14 L/min, the flow pattern is the single roll flow (SRF), and the risk of slag entrainment increases. With an argon gas flow rate of 10 L/min, and an immersion depth of 160 mm, the velocity near the mold surface sensitively increases with increasing the casting speed. When the casting speed is 1.1 m/min, an intermediate flow (IF) is formed with the intensified mold surface fluctuation, which can easily result in slag entrainment defects. When the casting speed is only increased to 1.2 m/min, the velocity near the mold surface changes drastically and is close to the upper limit velocity of 0.4 m/s. When the casting speed is 1.1 m/min, and the argon gas flow rate is 10 L/min, the velocity near the mold surface is obviously increased with increasing the immersion depth. When the immersion depth of the nozzle increases from 140 mm and 160 mm to 180 mm, the flow pattern changes from SRF or IF to DRF. When the bottom shape of the SEN changes from mountain to well, the velocity near the mold surface decreases. We suggest adopting the well-bottom nozzle to reduce the risk of slag entrainment.

The effects of argon gas flow rate and furnace pressure on oxygen concentration in Czochralski-grown silicon crystals

1998 ◽  
Vol 186 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Norihisa Machida ◽  
Youji Suzuki ◽  
Keisei Abe ◽  
Naoki Ono ◽  
Michio Kida ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Argon Gas ◽  
Silicon Crystals ◽  
Furnace Pressure

scholarly journals Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column

2020 ◽  
Vol 10 (13) ◽  
pp. 4617
Author(s):  
Adel Almoslh ◽  
Falah Alobaid ◽  
Christian Heinze ◽  
Bernd Epple
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volumetric Flow Rate ◽  
Interfacial Area ◽  
Gas Flow Rate ◽  
Test Rig ◽  
Flow Rates ◽  
Waste Gas ◽  
Simulated Waste ◽  
Series Of Experiments

The influence of pressure on the gas/liquid interfacial area is investigated in the pressure range of 0.2–0.3 MPa by using a tray column test rig. A simulated waste gas, which consisted of 30% CO2 and 70% air, was used in this study. Distilled water was employed as an absorbent. The temperature of the inlet water was 19 °C. The inlet volumetric flow rate of water was 0.17 m3/h. Two series of experiments were performed; the first series was performed at inlet gas flow rate 15 Nm3/h, whereas the second series was at 20 Nm3/h of inlet gas flow rate. The results showed that the gas/liquid interfacial area decreases when the total pressure is increased. The effect of pressure on the gas/liquid interfacial area at high inlet volumetric gas flow rates is more significant than at low inlet volumetric gas flow rates. The authors studied the effect of decreasing the interfacial area on the performance of a tray column for CO2 capture.

Effect of Inner Cavity’s Gas Flow Rate on the Extrusion Forming of Plastic Micro-Pipe

2020 ◽  
Vol 842 ◽  
pp. 279-284
Author(s):  
Zhong Ren ◽  
Xing Yuan Huang
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Flow Rate ◽  
Gas Flow ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
First Normal Stress Difference ◽  
Extrusion Forming

During the manufacture of plastic micro-pipe, a certain volume of gas should be properly injected into the inner cavity to overcome the collapse and adhesion problems. In this work, the extrusion forming of plastic micro-tube under the role of inner cavity’s gas were numerically studied. At the same time, the effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-pipe was also numerically investigated by using the finite element method. A kind of 2D two-phase fluid geometric model and finite element mesh were established and some reasonable boundary conditions and material parameters were imposed. Under a fixed volume flow rate of melt, different flow rates of inner cavity gas were imposed on the inlet of inner cavity’s gas. The extrusion deformation profile and deformation ratio of plastic micro-pipe under different flow rates of gas were all obtained. To ascertain the mechanisms of effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-tube, the flow velocities, pressure, shear rate, normal stress, and the first normal stress difference of melt all obtained and analyzed. Numerical results show that with the increase of inner cavity’s gas flow rate, the radial velocity, axial velocity, pressure, shear rate, normal stress, and the first normal stress difference of melt all increase, which makes the extrusion deformation become more and more serious. In practice, reasonable controlling of the inner cavity’s gas flow rate is very important. In the other hand, it can adjust the size of extruded plastic micro-pipe.

scholarly journals Optimization of Flow Field in Slab Continuous Casting Mold with Medium Width Using High Temperature Measurement and Numerical Simulation for Automobile Exposed Panel Production

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Peng Jiang ◽  
Jian Yang ◽  
Tao Zhang ◽  
Gangjun Xu ◽  
Hongjun Liu ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Gas Flow ◽  
Mold Surface ◽  
Level Fluctuation ◽  
Gas Flow Rate ◽  
Continuous Casting Mold ◽  
Argon Gas ◽  
Surface Level ◽  
Slab Continuous Casting

In the present work, mathematical modeling combined with measurement of the velocities near mold surface with rod deflecting method at the high temperature was carried out to optimize the flow field of slab continuous casting mold with medium width of 1230 mm for the production of an automobile exposed panel. The results show that the measured results of the velocities near the mold surface are in good agreement with the calculated results. The velocities near the mold surface increase with increasing the casting speed and decreasing the argon gas flow rate. When the casting speed is increased from 1.0, to 1.3, 1.5, and 2.0 m/min, the flow pattern in the mold is changed from single-roll flow (SRF), to unstable flow (UF), and then to double-roll flow (DRF), the top surface level fluctuations has the smallest value at 1.5 m/min. When the argon gas flow rate is 1 and 4 L/min, the velocity near the mold surface has a moderate value, and the flow pattern in the mold is DRF and the top surface level fluctuation is small and symmetrical. When the submerged entry nozzle (SEN) submergence depth is increased to 200 mm, the velocities near the mold surface decrease, and the top surface level fluctuation becomes small. The optimized flow field in the mold can be judged to be favorable to the surface quality of the automobile exposed panel; if the velocities near the mold surface are relatively small, the flow pattern in the mold is DRF and the top surface level fluctuation is small and symmetrical.

Effects of Gas Flow Rate and Catalyst Loading on Polymer Electrolyte Membrane (PEM) Fuel Cell Performance and Degradation

2010 ◽  
Author(s):  
A. Chukwujekwu Okafor ◽  
Hector-Martins Mogbo
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Catalyst Loading ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Electrolyte Membrane

In this paper, the effects of gas flow rates, and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50cm2 active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane Electrode Assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5mg/cm2, 1mg/cm2; 0.3L/min, 0.5L/min respectively) were tested at 60°C without humidification. The cell performance was analyzed by taking AC Impedance, TAFEL plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. TAFEL plot shows the highest exchange current density value of −2.05 mAcm2 for MEA with 0.5mg/cm2 catalyst loading operated at reactant gas flow rate of 0.3L/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.

High-Accuracy Wet-Gas Multiphase Well Testing and Production Metering

SPE Journal ◽  
2006 ◽  
Vol 11 (02) ◽  
pp. 199-205 ◽  
Author(s):  
David I. Atkinson ◽  
Oyvind Reksten ◽  
Gerald Smith ◽  
Helge Moe
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Volume Fraction ◽  
Well Testing ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Wet Gas ◽  
New Interpretation ◽  
Interpretation Model

Summary Dedicated wet-gas flowmeters are now commercially available for the measurement of gas and liquid flow rates and offer a more compact measurement solution than does the traditional separator approach. The interpretation models of traditional multiphase flowmeters emphasize the liquid rate measurements and have been used to well test and meter mostly liquid-rich flow streams. These models were not developed for the measurement of gas flow rates, particularly those of wet gas. A new interpretation is described that allows a traditional multiphase flowmeter to operate in a dual mode either as a multiphase meter or as a wet-gas meter in 90 to 100% gas. The new interpretation model was developed for a commercially available multiphase flowmeter consisting of a venturi and a dual-energy composition meter. This combination results in excellent predictions of the gas flow rate; the liquid rate prediction is made with acceptable accuracy and no additional measurements. The wet gas and low-liquid-volume-fraction interpretation model is described together with the multiphase flowmeter. Examples of applying this model to data collected on flow loops are presented, with comparison to reference flow rates. The data from the Sintef and NEL flow loops show an error (including the reference meter error) in the gas flow rate, better than ± 2% reading (95% confidence interval), at line conditions; the absolute error (including the reference meter error) in the measured total liquid flow rate at line conditions was better than ± 2 m3/h (< ± 300 B/D: 95% confidence interval). This new interpretation model offers a significant advance in the metering of wet-gas multiphase flows and yields the possibility of high accuracies to meet the needs of gas-well testing and production allocation applications without the use of separators. Introduction There has been considerable focus in recent years on the development of new flow-measurement techniques for application to surface well testing and flow-measurement allocation in multiphase conditions without separating the phases. This has resulted in new technology from the industry for both gas and oil production. Today, there are wet-gas flowmeters, dedicated to the metering of wet-gas flows, and multiphase meters, for the metering of multiphase liquid flows. The common approach to wet-gas measurement relates gas and liquid flows to a "pseudo-gas flow rate" calculated from the standard single-phase equations. This addresses the need for gas measurement in the presence of liquids and can be applied to a limit of liquid flow [or gas volume fraction, (GVF)], though the accuracy of this approach decreases with decreasing GVF. The accurate determination of liquid rates by wet-gas meters is restricted in range. The application and performance of multiphase meters has been well documented through technical papers and industry forums, and after several years of development is maturing (Scheers 2004). Some multiphase measurement techniques can perform better, and the meters provide a more compact solution, than the traditional separation approach. It is not surprising that the use of multiphase flowmeters has grown significantly, the worldwide number doubling in little over a 2-year period (Mehdizadeh et al. 2002). Multiphase-flowmeter interpretation emphasizes the liquid rate measurement, and the application of multiphase flowmeters has been predominantly for liquid-rich flow stream allocation and well testing.

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