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.

Simulation on Temperature Field of Gap Oil Film in Constant Flow Hydrostatic Center Frame

2011 ◽  
Vol 121-126 ◽  
pp. 4706-4710
Author(s):  
Yong Hai Li ◽  
Xiu Li Meng ◽  
Xiao Dong Yu ◽  
Bo Wu ◽  
Chun Li Gao ◽  
...  
Keyword(s):  
Temperature Field ◽  
Angular Velocity ◽  
Thermal Deformation ◽  
Three Dimensional ◽  
Constant Flow ◽  
Distribution Law ◽  
Simulation Research ◽  
Oil Film ◽  
Temperature Performance ◽  
Volume Method

In order to solve the thermal deformation of the hydrostatic center frame in the heavy type horizontal lathe, a simulation research concerning temperature field of hydrostatic center frame is described. The Finite Volume Method of CFX has been used to compute three-dimensional temperature field of gap fluid between workpiece and bearing pillow. This research theoretically analyzes the influence of angular velocity on the bearing temperature performance according to lubricating theory and computational fluid dynamics, and it has revealed its temperature distribution law of gap oil film. Results indicate that an improved characteristic will be affected by angular velocity easily, and oil cavity temperature increases by gradually with angular velocity enhancing. Through this method, the safety of a hydrostatic center frame can be forecasted, and the optimal design of such products can be achieved, so it can provide reasonable data for design, lubrication, experience and thermal deformation computation for hydrostatic center frame in the heavy type horizontal lathe.

Thermal Analysis and Optimization Design on Spindle Bearing of GSCK200A CNC Lathe

2011 ◽  
Vol 314-316 ◽  
pp. 1760-1763
Author(s):  
Le Ping Liu ◽  
Guo Hong Deng
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Optimization Design ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Clearance ◽  
Spindle Bearing ◽  
Heat Transfer Theory ◽  
Cnc Lathe ◽  
Three Dimensional Finite Element

Establish the three-dimensional finite element model of GSCK200A type High-speed & high-precision CNC Lathe spindle bearing, based on tribology and heat transfer theory, using ANSYS to analyze the corresponding temperature field and thermal deformation of spindle bearing in steady working state, according to this thermal deformation to obtain decrease volume of radial clearance, and the installation clearance optimization scheme is putted forward.

Thermal-stress analysis and calculation of single and dual chip set double-sided circuit board based on three-dimensional finite element algorithm

Circuit World ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 49-54
Author(s):  
Lan Song ◽  
Yang Zhao ◽  
Yaoming Zhou ◽  
Haifei Xiang
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Thermal Stress ◽  
Three Dimensional ◽  
Circuit Board ◽  
Content Type ◽  
Thermal Stress Field ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Element Algorithm

Purpose – The purpose of this paper is to analyze and figure out the temperature field and thermal stress field with the calculation model of thermal insulation material and composite material. Design/methodology/approach – The paper adopted the three-dimensional finite element algorithm. Findings – The simulated results showed great shearing strength between the chipset and the printed circuit board. The position of chip exerts great influence on the distribution of temperature field and thermal stress field of circuit board. The reasonable distribution of chip will effectively reduce the temperature extremum and stress extremum of circuit board. Originality/value – The paper analyzes and presents a discussion of the problems relating to the density of electronic packaging. The analysis process and the method of the paper provide essential help in resolving electronic device heat problems.

Research on Temperature Field of Hydrostatic Thrust Bearing with Annular Cavity Multi-Pad

2011 ◽  
Vol 121-126 ◽  
pp. 3477-3481
Author(s):  
Xiao Dong Yu ◽  
Xiu Li Meng ◽  
Bo Wu ◽  
Chun Li Gao ◽  
Zhi Xin Qiu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Temperature Field ◽  
Thermal Deformation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Distribution Law ◽  
Simulation Research ◽  
Temperature Performance ◽  
Simulation Results ◽  
Volume Method

A simulation research concerning temperature field of hydrostatic thrust bearing having annular cavities multi-pad was described in order to solve the thermal deformation of the hydrostatic thrust bearing with annular cavity multi-pad in the heavy CNC equipment. The Finite Volume Method of CFX has been used to compute three-dimensional temperature field of gap fluid between the rotation worktable and base. This study theoretically analyzes the influence of rotating velocity on the bearing temperature performance according to computational fluid dynamics and lubricating theory. It has revealed its temperature distribution law. The simulation results indicate that an improved characteristic will be affected by rotating velocity easily, and oil cavity temperature increases by gradually with rotating velocity enhancing. Through this method, the safety of a hydrostatic thrust bearing having annular cavities multi-pad can be forecasted, and the optimal design of such products can be achieved, so it can provide reasonable data for design, lubrication, experience and thermal deformation computation for hydrostatic thrust bearing in the heavy CNC equipment.

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.

Simulation Research on Temperature Field of Circular Cavity Hydrostatic Thrust Bearing

2009 ◽  
Vol 419-420 ◽  
pp. 141-144 ◽  
Author(s):  
Xiao Dong Yu ◽  
Xiu Li Meng ◽  
Bo Wu ◽  
Jun Peng Shao ◽  
Yan Qin Zhang ◽  
...  
Keyword(s):  
Temperature Field ◽  
Thermal Deformation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Circular Cavity ◽  
Cavity Radius ◽  
Distribution Law ◽  
Cavity Depth ◽  
Simulation Research ◽  
Heavy Equipment

In order to solve the thermal deformation of the hydrostatic thrust bearing in the heavy equipment, a simulation research concerning temperature field of multi-pad hydrostatic thrust bearing having circular cavities was described. The Finite Volume Method of Fluent has been used to compute three-dimensional temperature field of gap fluid between the rotation worktable and base. This study theoretically analyzes the influence of cavity radius and cavity depth on the bearing temperature performance according to computational fluid dynamics and lubricating theory. It has revealed its temperature distribution law. The simulation results indicate that an improved characteristic can be gotten from a circular cavity hydrostatic thrust bearing, oil cavity temperature decreases by gradually with cavity radius enhancing, oil cavity temperature decreases by gradually with cavity depth. Through this method, the safety of a hydrostatic thrust bearing having circular cavities multi-pad can be forecasted, and the optimal design of such products can be achieved, so it can provide reasonable data for design and lubrication and experience and thermal deformation computation for hydrostatic thrust bearing in the heavy equipment.

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 Simulation of Temperature Field of Direct Laser Metal Deposition Shaping Process of Titanium Alloys

2011 ◽  
Vol 295-297 ◽  
pp. 2112-2119
Author(s):  
Yuan Kong ◽  
Wei Jun Liu ◽  
Yue Chao Wang
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Thermal Stress ◽  
Stress Field ◽  
Molten Pool ◽  
Three Dimensional ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Forming Process ◽  
Direct Laser

In order to control the thermal stress of forming process, based on “element birth and death” technology of finite element method, a numerical simulation of three-dimensional temperature field and stress field during multi-track & multi-layer laser metal deposition shaping(LMDS) process is developed with ANSYS parametric design language (APDL). The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder and laser-powder. The temperature field, temperature gradient, thermal stress field and distribution of residual stress are obtained. The results indicate that although the nodes on different layers are activated at different time, their temperature variations are similar. The temperature gradients of samples are larger near the molten pool area and mainly along z-direction. Finally, it’s verified that the analysis results are consistent with actual situation by the experiments with same process parameters.

Cooling Effects of H-Beam after Rolling on Thermal Stress

2014 ◽  
Vol 898 ◽  
pp. 233-236
Author(s):  
Jin Hong Ma ◽  
Xiao Han Yao ◽  
Bin Tao ◽  
Shuo Li
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Stress Field ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Controlled Cooling ◽  
Fem Model ◽  
Transient Temperature Field ◽  
Cooling Effects ◽  
H Beam

Controlled cooling of H-beam after rolling, can change the microstructure consituent,improve the strength and improve the general mechanical property and service performance. According to actual product, the rational thermal boundary condition adopted, three dimensional FEM model is established. Spray cooling is used. Transient temperature field and stress field is simulated by the FEM software ANSYS/Multiphysics when H-beam is cooled. The four kinds of cooling scheme are designed. Through analysis of the relation of temperature field with stress field, the main reason of producing residual thermal stress is the section temperature difference in the cooling process of H-beam after rolling.

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