scholarly journals Research on the ingot shrinkage in the electroslag remelting withdrawal process for 9Cr3Mo roller

2019 ◽  
Vol 38 (2019) ◽  
pp. 672-682
Author(s):  
Wanming Li ◽  
Ximin Zang ◽  
Haiyang Qi ◽  
Dejun Li ◽  
Xin Deng
Keyword(s):  
Temperature Field ◽  
Yield Function ◽  
Joule Heat ◽  
Electroslag Remelting ◽  
Slag Bath ◽  
Magnetic Flux Density ◽  
Sequential Coupling ◽  
Field Velocity ◽  
Physical Fields ◽  
Good Agreement

AbstractIn order to reduce the air gap between ingot and mould in the electroslag remelting withdrawal (ESRW) process, the taper of the mould should be consistent with the ingot shrinkage.Athree-dimensional mathematical model was developed to describe the interaction of multiple-physical fields (Joule heat, electromagnetic field, velocity field, and temperature field) and ingot shrinkage during the ESRW process. The variations of material thermal and mechanical properties, as well as the yield function with temperature, were considered. The shrinkage behavior of 9Cr3Mo roller in the ESRW process was simulated using the sequential coupling method. A good agreement between the calculated value and the measured valuewas obtained in the temperature field and stress field. Numerical results showed that maximum values of current density, Joule heat, and electromagnetic forcewere at the electrode corner of the slag bath. The direction of the magnetic flux density was tangential to the slag bath and had a clockwise rotation. There were two pairs of vortices and two high temperature zones in the slag bath. The shrinkage displacement was obtained through thermal-stress analysis. As the distance from the mould outlet decreases, the shrinkage displacement of ingot increases. As for the electroslag remelting withdrawal process for 9Cr3Mo roller, the variation of the shrinkage displacement from the slag/metal interface to the mould outlet was 0.0028 m. The maximum shrinkage displacement is at the mould outlet, and the value was 0.0089 m.

scholarly journals A Comprehensive Mathematical Model of Electroslag Remelting with Two Series-Connected Electrodes Based on Sequential Coupling Simulation Method

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 658
Author(s):  
Wenjie Tong ◽  
Wanming Li ◽  
Ximin Zang ◽  
Huabing Li ◽  
Zhouhua Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Molten Metal ◽  
Skin Effect ◽  
Simulation Method ◽  
Melting Rate ◽  
Joule Heat ◽  
Electroslag Remelting ◽  
Metal Pool ◽  
Sequential Coupling ◽  
Molten Metal Pool

A comprehensive mathematical model of electroslag remelting with two series-connected electrodes (TSCE-ESR) was constructed based on sequential coupling method. The influence of droplet effect on electroslag remelting process (ESR) was considered in this model. Compared with one-electrode electroslag remelting (OE-ESR), the multi-physics field, droplet formation and dripping behavior, and molten metal pool structure of TSCE-ESR process were studied. The results show that during the process of TSCE-ESR, the proximity effect of the electrodes suppresses the skin effect, and Joule heat is concentrated in the area between the two electrodes of slag pool, making the temperature distribution of the slag pool more uniform. The heat used to melt the electrode in the process of TSCE-ESR accounts for about 34% of the total Joule heat, which is lower than the OE-ESR (17%). Therefore, it makes a higher melting rate and a smaller droplet size in the process of TSCE-ESR. Compared with OE-ESR, TSCE-ESR process can realize the unification of higher melting rate and shallow flat molten metal pool. Compared with the results without droplet effect, it is found that in the simulation results with droplet effect, the depth and the cylindrical section of molten metal pool increased, and the width of the mushy zone is significantly reduced, which is more consistent with the actual electroslag remelting process.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

2012 ◽  
Vol 516-517 ◽  
pp. 312-315
Author(s):  
Guang Hua Li ◽  
Hong Lei Liu ◽  
De Jian Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Heat Pipe ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Cooling Device ◽  
Transformer Design ◽  
Electrical Transformers ◽  
Good Agreement

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

scholarly journals Numerical Prediction of Far-Field Combustion Noise from Aeronautical Engines

Acoustics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 174-198 ◽  
Author(s):  
Mélissa Férand ◽  
Thomas Livebardon ◽  
Stéphane Moreau ◽  
Marlène Sanjosé
Keyword(s):  
Temperature Field ◽  
Low Power ◽  
Combustion Chamber ◽  
High Power ◽  
Acoustic Propagation ◽  
Combustion Noise ◽  
Far Field ◽  
Low Frequencies ◽  
Turboshaft Engine ◽  
Good Agreement

A hybrid methodology combining a detailed Large Eddy Simulation of a combustion chamber sector, an analytical propagation model of the extracted acoustic and entropy waves at the combustor exit through the turbine stages, and a far-field acoustic propagation through a variable exhaust temperature field was shown to predict far-field combustion noise from helicopter and aircraft propulsion systems accurately for the first time. For the single-stream turboshaft engine, the validation was achieved from engine core to the turbine exit. Propagation to the far field was then performed through a modeled axisymmetric jet. Its temperature modified the acoustic propagation of combustion noise significantly and a simple analytical model based on the Snell–Descarte law was shown to predict the directivity for axisymmetric single jet exhaust accurately. Good agreement with measured far-field spectra for all turboshaft-engine regimes below 2 kHz stresses that combustion noise is most likely the dominant noise source at low frequencies in such engines. For the more complex dual-stream turbofan engine, two regime computations showed that direct noise is mostly generated by the unsteady flame dynamics and the indirect combustion noise by the temperature stratification induced by the dilution holes in the combustion chamber, as found previously in the turboshaft case. However, in the turboengine, direct noise was found dominant at the combustor exit for the low power case and equivalent contributions of both combustion noise sources for the high power case. The propagation to the far-field was achieved through the temperature field provided by a Reynolds-Averaged Navier–Stokes simulation. Good agreement with measured spectra was also found at low frequencies for the low power turboengine case. At high power, however, turboengine jet noise overcomes combustion noise at low frequencies.

A Thermodynamic Model for Evaluation of Mass Action Concentrations of La2O3-Al2O3-CaF2-CaO-MgO Slags for Electroslag Remelting Based on the Ion and Molecule Coexistence Theory

2013 ◽  
Vol 32 (6) ◽  
pp. 541-550 ◽  
Author(s):  
Chengchuan Wu ◽  
Guoguang Cheng ◽  
Jun Tian
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Model ◽  
Mass Fraction ◽  
Electroslag Remelting ◽  
Mass Action ◽  
Coexistence Theory ◽  
Maximum Value ◽  
Mass Action Concentration ◽  
Increasing Temperature ◽  
Good Agreement

AbstractAccording to the ion and molecule coexistence theory (IMCT) for molten slags and corresponding phase diagrams, a thermodynamic model for the evaluation of mass action concentrations (designated by Ni for structure unit i) for La2O3-Al2O3, La2O3-Al2O3-CaF2, La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems for electroslag remelting (ESR) has been formulated. The influencing factors for the mass action concentration of La2O3, such as mass fraction of Al2O3, CaF2, CaO and MgO and temperature, were investigated. The results show that when the mole fraction of La2O3 is at 0.495, the mass action concentration of La2O3 · Al2O3 achieves its maximum value 0.946 in the La2O3-Al2O3 binary slag. In a composition area of La2O3: 10wt% ∼ 45wt%, Al2O3: 0wt% ∼ 50wt% and CaF2: 20wt% ∼ 70wt% of the La2O3-Al2O3-CaF2 ternary slag at 1873 K, the results show that the calculated values of NLa2O3 are in good agreement with the reported measured values of aLa2O3. The iso-curves of NLa2O3 is also drawn from the calculated results, which reveals that the mass action concentration of La2O3 decreases with the increasing of the Al2O3 and CaF2 content, and Al2O3 is stronger than CaF2 in decreasing the mass action concentration of La2O3. However, in La2O3-Al2O3-CaF2-CaO, La2O3-Al2O3-CaF2-MgO and La2O3-Al2O3-CaF2-CaO-MgO slag systems, the mass action concentration of La2O3 increases with the increasing of the MgO and CaO content, and CaO is stronger than MgO in increasing the mass action concentration of La2O3. In addition, the mass action concentration of La2O3 increases with the increasing temperature at the composition of 30wt%La2O3, 10wt%Al2O3, 40wt%CaF2, 10wt%MgO and 10wt%CaO.

scholarly journals Influence of different air supply parameters on indoor thermal comfort of upper air supply room

2021 ◽  
Vol 257 ◽  
pp. 03078
Author(s):  
Yan Wang ◽  
Zhuangzhuang Qu
Keyword(s):  
Temperature Field ◽  
Velocity Field ◽  
Field Distribution ◽  
Working Conditions ◽  
Indoor Temperature ◽  
Evaluation Indexes ◽  
Indoor Thermal Comfort ◽  
Air Supply ◽  
Field Velocity ◽  
Simulation Results

With the help of Airpak software, the evaluation indexes of temperature field, velocity field and PMV under different air supply parameters are explored. Through the analysis of different parameters of the air supply field, such as temperature and PMV, the evaluation index of the optimal air supply field was established. By comparing the differences of indoor flow field distribution under five different working conditions, the optimal air supply parameters are obtained, that is, when the air supply temperature is 23 °C and the air supply speed is 3.3 m / s, the indoor temperature field and velocity field distribution are the best. The simulation results provide a theoretical basis for the setting of air supply parameters in the upper air supply room.

scholarly journals Springback Calibration of a U-Shaped Electromagnetic Impulse Forming Process

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 603 ◽  
Author(s):  
Xiaohui Cui ◽  
Zhiwu Zhang ◽  
Hailiang Yu ◽  
Xiaoting Xiao ◽  
Yongqi Cheng
Keyword(s):  
Tangential Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Simulation Method ◽  
Discharge Voltage ◽  
Electromagnetic Forming ◽  
Forming Process ◽  
Sheet Bending ◽  
Sequential Coupling ◽  
Good Agreement

A three-dimensional (3D) finite-element model (FEM), including quasi-static stamping, sequential coupling for electromagnetic forming (EMF) and springback, was established to analyze the springback calibration by electromagnetic force. Results show that the tangential stress at the sheet bending region is reduced, and even the direction of tangential stress at the bending region is changed after EMF. The springback can be significantly reduced with a higher discharge voltage. The simulation results are in good agreement with the experiment results, and the simulation method has a high accuracy in predicting the springback of quasi-static stamping and electromagnetic forming.

Temperature Field and Refrigeration Output of Thermoelectric Arm

2011 ◽  
Vol 374-377 ◽  
pp. 508-511
Author(s):  
Yi Zhang ◽  
Huan Yang
Keyword(s):  
Experimental Data ◽  
Temperature Field ◽  
Experimental Methods ◽  
Joule Heat ◽  
Thermoelectric Cooler ◽  
Cold Side ◽  
Output Equation

Temperature field in thermoelectric arm and refrigeration output equation of a thermoelectric cooler was investigated by theoretical and experimental methods. Temperature differences between hot side and cold side were measured. Experimental data were used to prove the peak of the temperature parabola is located at hot side. The terms in refrigeration output equation can’t be explained as heat conducted from hot side to cold side and half of Joule heat respectively.

The Effect of Various Notches on the Prediction of the Ductile Fracture for SUS304 Sheets

2019 ◽  
Vol 794 ◽  
pp. 36-41
Author(s):  
Sai Jun Zhang ◽  
Yan Chun Lu ◽  
Zhao Hui Shen ◽  
Chi Zhou
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Constitutive Models ◽  
Yield Function ◽  
Finite Element Models ◽  
Ductile Fracture Criterion ◽  
Notch Radius ◽  
Fracture Locus ◽  
Notched Specimens ◽  
Good Agreement

In this study, the Drucker yield function and S-shaped strain hardening model are employed to describe the yielding and hardening behaviors of SUS304 respectively. An uncoupled ductile fracture criterion is calibrated and then utilized to construct the fracture locus of SUS304. To explore the effect of various notches on the prediction of ductile fracture, the constitutive models and ductile fracture criterion are then introduced into the ABAQUS/Explicit code to predict the onset of ductile fracture of various notched specimens. The comparison demonstrates that the ductile fracture criterion captures the fracture strains for all specimens with different notch radius accurately and the finite element models predict the strain distribution, strain evolution and load-stroke curves with good agreement for specimens with large notch radius compared with the experimental results.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

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