scholarly journals Flow Field and Temperature Field in a Four-Strand Tundish Heated by Plasma

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 722
Author(s):  
Mengjing Zhao ◽  
Yong Wang ◽  
Shufeng Yang ◽  
Maolin Ye ◽  
Jingshe Li ◽  
...  
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Molten Steel ◽  
Short Circuit ◽  
Plasma Heating ◽  
Three Dimensional ◽  
Heating Power ◽  
Flow State ◽  
Selection Of ◽  
Temperature Area

Tundish plasma heating is an effective method for achieving steady casting with low superheat and constant temperature. In order to study the flow field, temperature field in tundish heated by plasma, a three-dimensional transient mathematical model was established in the present work. A four-strand T-type tundish in a steelmaking plant was used to explore the changes in the flow field and temperature field of molten steel in the tundish under different plasma heating powers. The results showed that plasma heating affected the flow state of molten steel. It could eliminate the short-circuit flow at outlet. When the plasma heating was 500 kW, the molten steel had an obvious upward flow. The turbulence intensity was improved and distributed evenly with an increase in plasma heating power. In the prototype tundish, the temperature of the outlet was dropped by nearly 2–3 K within 300 s. With the increase of plasma heating power, the low temperature area in the tundish gradually was decreased. When the heating power was 1000 kW, the temperature difference of two outlets was 0.5 K and the overall temperature distribution was more uniform. The research results have a certain guiding significance for the selection of the actual plasma heating power on site.

Effects of U-Shape Inner Cooler on Flow and Solidification of Molten Steel in Slab Continuous Casting Mold

2011 ◽  
Vol 291-294 ◽  
pp. 423-427
Author(s):  
Yan Juan Jin ◽  
Xiao Chao Cui ◽  
Zhu Zhang
Keyword(s):  
Fluid Dynamics ◽  
Temperature Field ◽  
Flow Field ◽  
Continuous Casting ◽  
Molten Steel ◽  
Continuous Casting Mold ◽  
Slab Continuous Casting ◽  
Cooling Technology ◽  
Steel Flow

An inner-outer coupled cooling technology of molten steel for 1240×200mm slab continuous casting, that is to set an inner cooler—U shape pipes in the mold, is put forward in order to enhance the efficiency of transmitting heat and improve inner structure of billet. The flow status and solidification status of molten steel under coupling flow field and temperature field in inner-outer coupled cooling mold are simulated by using fluid dynamics software, and compare with those in traditional mold. It is found that setting inner cooler in the mold can make molten steel flow status even, which is favorable to floating up of the inclusion, quickening the solidification of steel liquid and improving the quality of billet.

Numerical Simulation of Inner-Outer Couple Cooling Slab Continuous Casting in the Filling Process

2012 ◽  
Vol 557-559 ◽  
pp. 2257-2260
Author(s):  
Yan Juan Jin ◽  
Xiao Chao Cui ◽  
Yan Xia Chen
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Continuous Casting ◽  
Molten Steel ◽  
Solidification Rate ◽  
Surface Shape ◽  
Filling Process ◽  
Slab Continuous Casting ◽  
Free Surface Shape ◽  
Steel Flow

In the paper, flow status and solidification status of molten steel in inner-outer couple cooling mold in the filling process are simulated by using fluid dynamics software Flow-3d, and obtain distributing diagrams of flow field and temperature field and free-surface shape diagrams in the filling process. Influences of flow field and temperature field of filling process on solidification are analyzed in the slab continuous casting. It is indicated that inner cooler can improve molten steel flow status, which is favorable to inclusion in molten steel floating up, quicken the solidification rate of molten steel in the mold.

Flow Dynamics and Film Cooling Effectiveness on a Non-Axisymmetric Contour Endwall in a Two-Dimensional Cascade Passage

2009 ◽  
Author(s):  
Gazi I. Mahmood ◽  
Ross Gustafson ◽  
Sumanta Acharya
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Film Cooling ◽  
Free Stream ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Cooling Flow ◽  
Blowing Ratio

The measured flow field and temperature field near a three-dimensional asymmetric contour endwall employed in a linear blade cascade are presented with and without film-cooling flow on the endwall. Flow field temperature and Nusselt number distributions along the asymmetric endwall with wall heating and no film-cooling flow are also reported to show local high heat transfer region on the endwall and justify the locations of the coolant holes. Adiabatic film-cooling effectiveness along the endwall is then measured to indicate the local effects of the coolant jets. The near endwall flow field and temperature field provide the coolant flow behavior and the interaction of coolant jets with the boundary layer flow. Thus, the local film-cooling effectiveness can be explained with the coolant jet trajectories. The measurements are obtained at the Reynolds number of 2.30×105 based on blade actual chord and inlet velocity, coolant-to-free stream temperature ratio of 0.93, and coolant-to-free stream density ratio of 1.06. The cascade employs the hub side blade section and passage geometry of the first stage rotor of GE-E3 turbine engine. The contour endwall profile is employed on the bottom endwall only in the cascade. The blowing ratio of the film-cooling flow varies from 1.0 to 2.4 from 71 discrete cylindrical holes located in the contour endwall. The three-dimensional profile of the endwall varies in height in both the pitchwise and axial directions. The flow field is quantified with the streamwise vorticity and turbulent intensity, pitchwise static pressure difference, flow yaw angle, and pitchwise velocity. Both the flow field and temperature data indicate that the coolant jets cover more distance in the pitchwise and axial direction in the passage as the blowing ratio increases. Thus, the local and average film-cooling effectiveness increase with the blowing ratio.

Numerical Simulation of Flow Process of Ammonium Persulfate Crystallizer

2014 ◽  
Vol 997 ◽  
pp. 396-400
Author(s):  
Yu Guang Fan ◽  
Ting Wei
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Ammonium Persulfate ◽  
Flow Process ◽  
Calculation Results ◽  
Crystallization Effect ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Selection Of

The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.

scholarly journals Flow Characteristics for Two-Strand Tundish in Continuous Slab Casting Using PIV

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 239 ◽  
Author(s):  
Jun Huang ◽  
Zhigang Yuan ◽  
Shaoyuan Shi ◽  
Baofeng Wang ◽  
Chi Liu
Keyword(s):  
Flow Field ◽  
Molten Steel ◽  
Similarity Theory ◽  
Vortex Motion ◽  
Surface Velocity ◽  
Outlet Section ◽  
Intensity Increase ◽  
Geometrical Shape ◽  
Flow State ◽  
Slab Casting

With the development of continuous casting technology, there has been an increase in the stringent requirements for the cleanliness and quality of steel being produced. The flow state of molten steel in tundish is the key to: Optimizing the residence time of molten steel in the tundish; homogenizing the temperature of molten steel; and removing inclusions by floatation. Hence, from theoretical and practical aspects, it is imperative to examine and analyze the flow field of molten steel in the tundish in order to ensure the desired molten steel flow. In this study, a two-strand tundish with 650 mm × 180 mm slab casting is considered as the subject for this research. According to the similarity theory, combined with the geometrical shape and dimension of the prototype tundish, a tundish model with a geometric similarity ratio of 2:3 is established in the laboratory. Digital particle image velocimetry (PIV) is employed to measure and examine the flow fields at different casting speeds for a tundish containing different flow control devices. The flow in the tundish is typically turbulent and also consists of a vortex motion; it exhibits both random and ordered characteristics. Results reveal that the presence of baffles with 15° holes can cause an upward-directed flow in the outlet section and give rise to a large circulation. When the casting speed is doubled, the overall velocity of the flow field and turbulent intensity increase, leading to an increase in the molten steel surface velocity.

scholarly journals Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1252
Author(s):  
Junqing Li ◽  
Luo Wang
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Thermal Deformation ◽  
Short Circuit ◽  
Three Dimensional ◽  
Static Field ◽  
Heat Transfer Theory ◽  
Circuit Fault Diagnosis ◽  
Rotor Winding ◽  
Magnetic Poles

Rotor winding inter-turn short circuit a common fault in hydro-generators. This fault would change the temperature, stress, and other thermal fields of a rotor and threaten the safe operation of the generator. In this paper, the Three Gorges hydro-generator is taken as an example. Mathematical models of three-dimensional temperature field and thermal stress field of rotor magnetic poles are established based on heat transfer theory and solved by finite element method. The temperature field, thermal deformation, and thermal stress distribution of magnetic poles in rotor winding inter-turn short circuit are calculated. On the basis of the calculation, the effects of the different turn numbers and positions of short circuit on the temperature, thermal deformation, and thermal stress of rotor magnetic poles are further studied. It is concluded that the thermal stress of the winding adjacent to the shorted turn would decrease, the thermal stress of the winding farther away from the shorted winding would increase, and so on. The results of this paper can provide references for inter-turn short circuit fault diagnosis and lay a foundation for the further studies of related faults.

Numerical Simulation of Effect on Billet Casting Q235 under Inner-Out Cooler

2011 ◽  
Vol 308-310 ◽  
pp. 651-655
Author(s):  
Lang Li ◽  
Guo Ping Chen
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Flow Field ◽  
Molten Steel

There is a new idea on the billet casting Q235 with size of 165mm×165 mm,It involves a couple technology to cool molten steel both from inside and outside, namely: to emplace an inner cooler -a pipe with the shape of letter U in the mould. It aims to increase the thermal conductivity and improve the inner structure of the billet. With the help of Fluent -a kind of CFD business soft ware, a numerical simulation is undertaken to testify the condition of the molten steel in the inner-outer cooling mould coupled by flow field and temperature field.

scholarly journals Multifield Calculation and Analysis of Excitation Winding Interturn Short Circuit Fault in Turbo-Generator

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2626 ◽  
Author(s):  
Minghan Ma ◽  
Yonggang Li ◽  
Yucai Wu ◽  
Chenchen Dong
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Temperature Field ◽  
Stress Field ◽  
Short Circuit ◽  
Three Dimensional ◽  
Turbo Generator ◽  
Dimensional Finite Element ◽  
Air Gap Magnetic Field ◽  
Excitation Winding

Excitation winding interturn short circuit (EWISC) is a common fault in turbo-generators. Once the fault occurs, if not handled in time, it will result in significant security risks to the power system. Using the multifield characteristics of fault generators for a comprehensive diagnosis can make the diagnostic results more accurate and credible. In this paper, taking a TA-1100-78 type, two pole pairs turbo-generator as the research object, the two-dimensional finite element electromagnetic model of stator/rotor and the three-dimensional finite element heat transfer model of rotor were established. The electromagnetic field, temperature field, and stress field of the generator were simulated and analyzed. At the same time, the air gap magnetic field, three-dimensional temperature field, and stress field distribution of the rotor were calculated for EWISC faults in different fault degrees and positions. The results showed that the EWISC fault weakened the air gap magnetic field and caused unbalanced electromagnetic distribution. At the same time, it caused a distortion of the rotor temperature field, resulting in an unbalanced distribution of the temperature field. The stress field was affected by the distortion of temperature field, and the local thermal stress increased but did not exceed the yield limit of the material. Restorable elastic deformation occurred when the rotor was heated, which caused the thermal bending of the rotor. The method adopted in this paper can provide a reference for the calculation of multiphysical field after a generator fault. It is also pointed out that the thermal unbalance influence should not be neglected in the study of generator vibration characteristics.

Numerical Analysis of Pressure Fluctuation in Circulating Water Pump Using CFD

2012 ◽  
Author(s):  
Cui Dai ◽  
Fan-Yu Kong ◽  
Liang Dong
Keyword(s):  
Flow Field ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Primary Source ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Flow State ◽  
Virtual Sensors ◽  
Rotor Stator Interaction

Pressure fluctuations acting on centrifugal pump contain a lot of dynamic information, such as rotor-stator interaction, vortex, backflow, and so on. By CFD method, calculations of three-dimensional unsteady flow in the suction chamber, impeller, annular chamber, inlet and outlet were conducted with sliding mesh technology. For the simulation of inner flow field, a commercial code Fluent had been used to predict the pulsating pressures. The shear stress transport turbulence model (SST k-ω) was confirmed through comparison with the hydraulic performance experiment. The change of static pressure was recorded by means of virtual sensors placed at the impeller-annular chamber interface and the tongue. And the pulsating pressures in the impeller passage were recorded to reflect its flow state. Then, amplitude domain analysis and frequency domain analysis were conducted to process those fluctuating pressure signals obtained under different opening conditions. The results indicate that the effect of rotor-stator interaction and vortexes to pressure fluctuations in flow field is obvious. The pressure fluctuation around impeller-chamber interface and tongue is affected by the interaction between blade and tongue definitely, and the various positions of the blade relative to the tongue lead to different trends of variation of pressure distribution. The primary source of pressure fluctuation in the impeller passage is associated with vortexes.

scholarly journals Flow Field, Temperature Field, and Inclusion Removal in a New Induction Heating Tundish with Bent Channels

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 561 ◽  
Author(s):  
Fei Xing ◽  
Shuguo Zheng ◽  
Zonghui Liu ◽  
Miaoyong Zhu
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Induction Heating ◽  
Flow Characteristics ◽  
Heating Power ◽  
Inclusion Removal ◽  
Good Efficiency ◽  
Heating Efficiency ◽  
Channel Radius ◽  
Field Temperature

In order to study the flow field, temperature field, and inclusion removal in a new induction heating tundish with bent channels, a three-dimensional (3D) transient mathematical model is established. The effects of both the channel radius and heating power on the multi-physical field and inclusion removal in the bent channels’ induction heating tundish are investigated. The results show that the tundish with the channel radius of 3 m shows better flow characteristics than those with the channel radii of 4 m and 2 m. With the increase of channel length, the heating efficiency increases at first, and then decreases, while the radius of 3 m is the best one for heating efficiency. After all the inclusions are placed into the tundish, the radii of 3 m and 2 m show good efficiency regarding inclusion removal, while it is poor when the radius is 4 m. Therefore, 3 m is the optimal radius of the channel in this work. Under the optimal channel radius, the heating power of 800 kW seems better than those of 600 kW and 1000 kW on flow characteristics control in the tundish. The temperature in the receiving chamber rises gradually and distributes quite uniformly with the increasing heating power, and the removal rate of inclusions increases with the increasing heating power.

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