scholarly journals Effect of Nitrogen Flow Ratio on Degradation Behaviors and Failure of Magnetron Sputter Deposited Tantalum Nitride

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1133
Author(s):  
Zhigang Li ◽  
Yubao Zhang ◽  
Yi Wang ◽  
Jinfeng Li ◽  
Hongtao Zhao
Keyword(s):  
Sheet Resistance ◽  
Flow Rate ◽  
Gas Flow ◽  
Adhesion Force ◽  
Tantalum Nitride ◽  
Nitrogen Flow ◽  
Flow Ratio ◽  
Gas Flow Rate ◽  
Heating And Cooling ◽  
Degradation Behaviors

A series of Tantalum Nitride (TaN) films under a reactive direct current magnetron sputtering method with a controlled total gas flow rate were prepared on aluminum oxide substrates. To find the nitrogen flow rate, which produced the minimum sheet resistance, TaN films deposited under a nitrogen gas flow ratio of 2.5%, 5%, 10%, 15%, 20%, 25% were characterized in terms of their structural and electrical properties. The optimum total gas flow rate was 60 sccm, revealing the lowest deviation of sheet resistance. Next, the durability and reliability at high temperatures, after heating and cooling cycles and exposure to the induced current, were tested. When the nitrogen flow ratio reaches 2.5%, it gets the maximum for the adhesion force, roughness, and deposition rate of the TaN film, and maximum values are 75.4 N, 1.1 nm, and 3.67 nm/min, respectively, and the sheet resistance of the TaN film reaches a minimum of 20.32 Ω/sq. The degradation behaviors and failure of TaN films were investigated by measuring the sheet resistance variation. To further explain the degradation of TaN films, additional analysis of their crystallinity was conducted. The results showed that TaN-based thin film resistors have high durability and reliability, and are suitable for embedded passive resistors.

scholarly journals Effect of Differentiated Injection Ratio, Gas Flow Rate, and Slag Thickness on Mixing Time and Open Eye Area in Gas-Stirred Ladle Assisted by Physical Modeling

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 555 ◽  
Author(s):  
Luis E. Jardón-Pérez ◽  
Daniel R. González-Morales ◽  
Gerardo Trápaga ◽  
Carlos González-Rivera ◽  
Marco A. Ramírez-Argáez
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Mixing Time ◽  
Flow Ratio ◽  
Gas Flow Rate ◽  
Nsga Ii ◽  
Image Velocimetry ◽  
Gas Flow Ratio ◽  
Slag Thickness ◽  
Injection Ratio

In this work, the effects of equal (50%/50%) or differentiated (75%/25%) gas flow ratio, gas flow rate, and slag thickness on mixing time and open eye area were studied in a physical model of a gas stirred ladle with dual plugs separated by an angle of 180°. The effect of the variables under study was determined using a two-level factorial design. Particle image velocimetry (PIV) was used to establish, through the analysis of the flow patterns and turbulence kinetic energy contours, the effect of the studied variables on the hydrodynamics of the system. Results revealed that differentiated injection ratio significantly changes the flow structure and greatly influences the behavior of the system regarding mixing time and open eye area. The Pareto front of the optimized results on both mixing time and open eye area was obtained through a multi-objective optimization using a genetic algorithm (NSGA-II). The results are conclusive in that the ladle must be operated using differentiated flow ratio for optimal performance.

Effects of Slitting Size and Inlet Operating Conditions on Hydrogen Combustion Characteristics in a Micro-Combustor With a Controllable Vortex Slotted Bluff Body

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Yunfei Yan ◽  
Kaiming Shen ◽  
Yu Cui ◽  
Ziqiang He ◽  
Li Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Bluff Body ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Flow Ratio ◽  
Gas Flow Rate ◽  
Slit Size ◽  
Micro Combustor

Abstract Effects of controllable vortex slotted bluff body parameters (position of a bluff body, slit size, and controllable flow ratio) on the combustion characteristics of hydrogen/air in a micro-combustor with a bluff body were investigated numerically. The results illustrated that the combustion efficiency of hydrogen decreases with increasing distance (L1) between the front edge of the bluff body and the combustor inlet. The combustion characteristics of the micro-combustor are optimum when L1 is 0 mm. The blow-off limit of the combustor reaches a maximum (564 cm3/s) when the slit width (d) is 20% of the bluff body width. The blow-off limit first increases and then decreases when the equivalence ratio (φ) increases and reaches a maximum (732 cm3/s) when φ is 1.0, and the controllable flow ratio is 0.2. The combustion efficiency of hydrogen is gradually increased with the increase in the controllable flow ratio. When φ is less than 1.0, the optimal controllable flow ratio gradually decreases with the increase in the premixed gas flow rate, and the optimal controllable flow ratio basically remains at 0.6 when the premixed gas flow rate is less than 360 cm3/s.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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