scholarly journals Development of technological regulation for carbon ironing of iron in 30t ladle. Part 1

2019 ◽  
pp. 129-142
Author(s):  
V.P. Piptyuk ◽  
A.S. Vergun ◽  
S.V. Grekov ◽  
S.E. Samohvalov ◽  
K.S. Krasnikov
Keyword(s):  
Numerical Simulation ◽  
Cast Iron ◽  
Numerical Study ◽  
Thermal Conditions ◽  
Temperature Fields ◽  
Low Carbon ◽  
Cored Wire ◽  
Titanium Slag ◽  
Flow Rates ◽  
Energy Balances

The results of numerical simulation of the carbonization of low-carbon iron as a by-product of the production of titanium slag for the designed unit ladle-furnace (LF) installation as applied to the conditions of PJSC Zaporizhzhya Titanium-Magnesium Combine are presented. The technological regulations have been developed and a numerical study has been carried out on the carburization of metal in a 30-ton ladle at the LF. For the production of commercial pig iron, associated iron-containing waste is used. The purpose of the work is to identify factors of the influence of out-of-furnace processing on technology optimization. A numerical simulation was performed of the carburization technology of liquid low-carbon (up to 2% carbon) cast iron with lump (fraction up to 50 mm) graphite and coke introduced onto the surface of a ladle bath (excluding slag cover). The material and energy balances of the process were carried out, the properties of carburizing materials were studied, and the diffusion coefficient of carbon in a liquid metal was estimated. The results of studies of the hydrodynamic and thermal conditions in the bucket bath of the LF are estimated from the contour diagrams of the flow rates and temperature fields for different flow rates of argon supplied through the bottom and submerged tuyeres. The optimal fractions of carbon-containing materials were determined. It has been shown that treatment on LF with lump graphite requires a shorter duration (≈ 45%) compared with lump coke. To accelerate the process of diffusion dissolution of carbon, it is necessary to periodically (every 3 portions of 70 kg of graphite and coke) heat the melt to a temperature of 1520-1530 ° C. Injection of powdered graphite and coke contributes to a more efficient absorption of carbon and a decrease in the duration of the process (≈ by 1/3). Research continues in the direction of using flux-cored wire for carburizing cast iron at LF.

scholarly journals Numerical Simulation of Secondary Flow in Gas Turbine Disc Cavities, Including Conjugate Heat Transfer

1996 ◽  
Author(s):  
Y.-H. Ho ◽  
M. M. Athavale ◽  
J. M. Forry ◽  
R. C. Hendricks ◽  
B. M. Steinetz
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Conjugate Heat Transfer ◽  
Gas Flow ◽  
Numerical Study ◽  
Labyrinth Seal ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Flow Rates ◽  
Turbine Disc

A numerical study of the flow and heat transfer in secondary flow elements of the entire inner portion of the turbine section of the Allison T-56/501D engine is presented. The flow simulation included the interstage cavities, rim seals and associated main path flows, while the energy equation also included the solid parts of the turbine disc, rotor supports, and stator supports. Solutions of the energy equations in these problems usually face the difficulty in specifications of wall thermal boundary conditions. By solving the entire turbine section this difficulty is thus removed, and realistic thermal conditions are realized on all internal walls. The simulation was performed using SCISEAL, an advanced 2D/3D CFD code for predictions of fluid flows and forces in turbomachinery seals and secondary flow elements. The mass flow rates and gas temperatures at various seal locations were compared with the design data from Allison. Computed gas flow rates and temperatures in the rim and labyrinth seal show a fair 10 good comparison with the design calculations. The conjugate heat transfer analysis indicates temperature gradients in the stationary intercavity walls, as well as the rotating turbine discs. The thermal strains in the stationary wall may lead to altered interstage labyrinth seal clearances and affect the disc cavity flows. The temperature, fields in the turbine discs also may lead to distortions that can alter the rim seal clearances. Such details of the flow and temperature fields are important in designs of the turbine sections to account for possible thermal distortions and their effects on the performance. The simulation shows that the present day CFD codes can provide the means to understand the complex flow field and thereby aid the design process.

Unsteady Radial Forces on the Impeller of a Centrifugal Pump With Radial Gap Variation

2003 ◽  
Author(s):  
Jose´ Gonza´les ◽  
Carlos Santolaria ◽  
Jorge Luis Parrondo ◽  
Joaqui´n Ferna´ndez ◽  
Eduardo Blanco
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Numerical Study ◽  
Unsteady Forces ◽  
Flow Rates ◽  
Blade Passage ◽  
Pressure Distributions ◽  
Dynamic Forces ◽  
Radial Forces ◽  
Radial Gap

An experimental and numerical study is presented on the unsteady radial forces produced in a centrifugal pump with volute casing. Two impellers with different outlet diameter were considered, which gave radial gaps between blade and tongue of 10% and 15.8% of the impeller radius, respectively. Firstly, the data from pressure fluctuation measurements was processed to obtain the dynamic forces at the blade-passage frequency, for a number of flow-rates. Afterwards, these results were used to check the predictions from a numerical simulation of the pump with the code Fluent. This paper describes the work carried out and summarizes the experimental and the numerical results, for both radial gaps. The steady and unsteady forces at the blade passing frequency obtained by radial integration of the pressure distributions in the shroud side of the pump volute are analysed in detail and similar trends are obtained.

A Numerical Study on the Heating of a Cast Iron Slab in a Car-Hearth Furnace

1996 ◽  
Vol 118 (4) ◽  
pp. 667-671
Author(s):  
Miroslav Jicha ◽  
John C. Chai ◽  
Suhas V. Patankar
Keyword(s):  
Cast Iron ◽  
Numerical Study ◽  
Temperature Fields ◽  
Uniform Temperature ◽  
Heating Period ◽  
Hearth Furnace ◽  
Transient Heating ◽  
Uniform Temperature Field ◽  
Velocity And Temperature Fields ◽  
Reduction Of Energy Consumption

A numerical study on the transient heating of a cast iron slab in a car-hearth furnace is presented. The influence of the direction of jets issuing from the burners on the velocity and temperature fields during the heating period was investigated. The standard k-ε turbulence model is used in the present study. It is found that the direction of the jets has a significant influence on the temperature distribution in the slab. It is also shown that inclined jets produce a more uniform temperature field and that the time needed for the slab to reach a predetermined temperature can be significantly reduced which results in the reduction of energy consumption.

scholarly journals Development of Depth-Limited Wave Boundary Layers over a Smooth Bottom

2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Wave Motion ◽  
Numerical Study ◽  
Experiment Data ◽  
Tidal Motion ◽  
Long Period ◽  
Simulation Results ◽  
Wave Boundary

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.

A numerical study on combined baffles quick-separation device

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ehsan Dehdarinejad ◽  
Morteza Bayareh ◽  
Mahmud Ashrafizaadeh
Keyword(s):  
Turbulent Flows ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Turbulence Models ◽  
Complete Separation ◽  
Solid Particles ◽  
Flow Rates ◽  
Separation Device ◽  
Coupling Technique ◽  
Laminar And Turbulent Flows

Abstract The transfer of particles in laminar and turbulent flows has many applications in combustion systems, biological, environmental, nanotechnology. In the present study, a Combined Baffles Quick-Separation Device (CBQSD) is simulated numerically using the Eulerian-Lagrangian method and different turbulence models of RNG k-ε, k-ω, and RSM for 1–140 μm particles. A two-way coupling technique is employed to solve the particles’ flow. The effect of inlet flow velocity, the diameter of the splitter plane, and solid particles’ flow rate on the separation efficiency of the device is examined. The results demonstrate that the RSM turbulence model provides more appropriate results compared to RNG k-ε and k-ω models. Four thousand two hundred particles with the size distribution of 1–140 µm enter the device and 3820 particles are trapped and 380 particles leave the device. The efficiency for particles with a diameter greater than 28 µm is 100%. The complete separation of 22–28 μm particles occurs for flow rates of 10–23.5 g/s, respectively. The results reveal that the separation efficiency increases by increasing the inlet velocity, the device diameter, and the diameter of the particles.

Thermal comfort analysis of a high-speed train cabin considering the solar radiation effects

2019 ◽  
Vol 29 (8) ◽  
pp. 1101-1117
Author(s):  
Lin Yang ◽  
Xiangdong Li ◽  
Jiyuan Tu
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
High Speed ◽  
Radiation Effects ◽  
Numerical Study ◽  
Thermal Conditions ◽  
Long Distance ◽  
High Speed Rail ◽  
Hot Weather ◽  
Cabin Environment

Due to the fast development of high-speed rail (HSR) around the world, high-speed trains (HSTs) are becoming a strong competitor against airliners in terms of long-distance travel. Compared with airliner cabins, HST cabins have much larger window sizes. When the big windows provide better lighting and view of the scenery, they also have significant effects on the thermal conditions in the cabins due to the solar radiation through them. This study presents a numerical study on the solar radiation on the thermal comfort in a typical HST cabin. The effect of solar radiation was discussed in terms of airflow pattern, temperature distribution and thermal comfort indices. Parametric studies with seven different daytime hours were carried out. The effect of using the roller curtain was also studied. The overall cabin air temperature, especially near passengers, was found to have significantly increased by solar radiation. Passengers sitting next to windows were recorded to have an obvious thermal comfort variation at different hours of the day. To improve the passengers’ comfort and reduce energy consumption during hot weather, the use of a curtain could effectively reduce the solar radiation effect in the cabin environment.

Numerical Simulation of Premixed Propane/Air Flame Propagation Using a Dynamically Thickened Flame Approach

2013 ◽  
Vol 444-445 ◽  
pp. 1574-1578 ◽  
Author(s):  
Hua Hua Xiao ◽  
Zhan Li Mao ◽  
Wei Guang An ◽  
Qing Song Wang ◽  
Jin Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Flame Propagation ◽  
Numerical Study ◽  
Vortex Motion ◽  
Combustion Process ◽  
Single Step ◽  
Premixed Combustion ◽  
Premixed Flame ◽  
Flame Surface ◽  
Arrhenius Kinetics

A numerical study of premixed propane/air flame propagation in a closed duct is presented. A dynamically thickened flame (TF) method is applied to model the premixed combustion. The reaction of propane in air is taken into account using a single-step global Arrhenius kinetics. It is shown that the premixed flame undergoes four stages of dynamics in the propagation. The formation of tulip flame phenomenon is observed. The pressure during the combustion process grows exponentially at the finger-shape flame stage and then slows down until the formation of tulip shape. After tulip formation the pressure increases quickly again with the increase of the flame surface area. The vortex motion behind the flame front advects the flame into tulip shape. The study indicates that the TF model is quite reliable for the investigation of premixed propane/air flame propagation.

Numerical Simulation of Temperature Field on Different Surface Structure of Bicycle Brake Pairs

2014 ◽  
Vol 697 ◽  
pp. 235-238
Author(s):  
Gang Wu ◽  
Can Chao Huang ◽  
Hong Ling Qin ◽  
Chun Hua Zhao
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Surface Structure ◽  
Surface Structures ◽  
Temperature Fields ◽  
Transfer Model ◽  
Pair Model ◽  
Layer Composite ◽  
Positive Effect ◽  
Heat Loads

Using the basic principle of heat transfer, tribology and numerical simulation, a two-dimensional heat transfer model of the three-layer composite brake pair materials were established. The temperature fields of brake pairs during the process of friction were analyzed. Applied given heat loads at different time node on the brake pair model, the temperatures of different bicycle brake pairs were compared and analyzed. Results show that the improved surface structures of brake pair have positive effect on decreasing the temperature of contact areas than that of ordinary surface structure.

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