Modeling for 3-D Temperature Field of Oil-Immersed Transformer

2011 ◽  
Vol 199-200 ◽  
pp. 1487-1491
Author(s):  
Su Xiang Qian ◽  
Ju Wu Xu ◽  
Xiao Jun Gu
Keyword(s):  
Temperature Field ◽  
Heat Exchange ◽  
Flow Field ◽  
Computer Experiment ◽  
Geometrical Model ◽  
Actual Situation ◽  
Traditional Methods ◽  
Ansys Cfx

The knowledge of temperature field of oil-filled transformer directly related to the judgment of overheated fault. There are mainly heat exchange, convection and their coupling in the transformer. Lot of traditional methods are not enough direct-viewing, and ignore the actual situation. The geometrical model of the transformer first modeled by Solidworks, and then ANSYS CFX is used to simulate the temperature field and flow field. Get a set of computer experiment result which can be reference. This computer experiment bring forth the method and effect of the simulate using that software, and make a foundation for the research of transformer overheated fault.

Conjugate Heat Transfer Analysis of a Rectangular Cooling Channel With 45-Deg Ribs

2015 ◽  
Author(s):  
Jiangnan Zhu ◽  
Tieyu Gao ◽  
Jun Li ◽  
Gojun Li ◽  
Jianying Gong
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Field ◽  
Flow Field ◽  
Conjugate Heat Transfer ◽  
Channel Wall ◽  
Outer Wall ◽  
Wall Region ◽  
Cooling Channel ◽  
Ansys Cfx

A conjugate heat transfer simulation of air in a rectangular cooling channel with 45-deg ribs is presented in this paper. The test channel length is 400mm and the ratio of width to height is 1. The hydraulic diameter of the channel is 40mm and the thickness of channel wall is 3mm. The rib height is 1.9mm and the distance between nearby ribs is 19mm. The flow field and the temperature field in the solid channel are obtained by using ANSYS CFX. An energy source is added in the solid domain to simulate the Low-Voltage High-Current heating method in the experiment. The GGI method is adopted for the mesh connection between the fluid domain and solid domain. The SST turbulence model and automatic wall function in ANSYS CFX are used to simulate the flow and heat transfer in near-wall region. The numerical results show great agreement with the experimental data. The temperature distribution on the channel outer wall is shown and analyzed. The Nusselt number field on the channel wall is shown and illustrated by the flow field shown by the Vortex Core Technology. There are four secondary flow vortex cores between ribs in near wall region and a strong secondary flow can be seen in main flow region. The angled ribs leads to the unbalanced temperature and Nusselt number field on the outer wall and the inner wall of the channel respectively. The distribution law of the Nusselt number on inner wall is not similar with the one of temperature on the outer wall. But the overall distribution of outer wall temperature field is more homogeneous compared with that of the inner wall Nusselt number. Some recommendations for optimization are given based on the flow field and Nusselt number distribution.

Numerical Analysis of Flow Fields and Temperature Fields in a Regenerative Heating Furnace for Steel Pipes

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Yi Han ◽  
Feng Liu ◽  
Xin Ran
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Gas Flow ◽  
Flow Fields ◽  
Heating Furnace ◽  
Temperature Fields ◽  
Turbulent Layer ◽  
Steel Pipes ◽  
Pipe Blanks

In the production process of large-diameter seamless steel pipes, the blank heating quality before roll piercing has an important effect on whether subsequently conforming piping is produced. Obtaining accurate pipe blank heating temperature fields is the basis for establishing and optimizing a seamless pipe heating schedule. In this paper, the thermal process in a regenerative heating furnace was studied using fluent software, and the distribution laws of the flow field in the furnace and of the temperature field around the pipe blanks were obtained and verified experimentally. The heating furnace for pipe blanks was analyzed from multiple perspectives, including overall flow field, flow fields at different cross sections, and overall temperature field. It was found that the changeover process of the regenerative heating furnace caused the temperature in the upper part of the furnace to fluctuate. Under the pipe blanks, the gas flow was relatively thin, and the flow velocity was relatively low, facilitating the formation of a viscous turbulent layer and thereby inhibiting heat exchange around the pipe blanks. The mutual interference between the gas flow from burners and the return gas from the furnace tail flue led to different flow velocity directions at different positions, and such interference was relatively evident in the middle part of the furnace. A temperature “layering” phenomenon occurred between the upper and lower parts of the pipe blanks. The study in this paper has some significant usefulness for in-depth exploration of the characteristics of regenerative heating furnaces for steel pipes.

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.

scholarly journals Heat exchange performance optimization of a wheel loader cooling system based on computational fluid dynamic simulation

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401880398 ◽  
Author(s):  
Chao Yu ◽  
Sicheng Qin ◽  
Yang Liu ◽  
Bosen Chai
Keyword(s):  
Heat Exchange ◽  
Flow Field ◽  
Thermal Management ◽  
Cooling System ◽  
Management Model ◽  
Maximum Deviation ◽  
Engine Compartment ◽  
Wheel Loader ◽  
Exchange Performance ◽  
Transmission Oil

This study establishes a thermal management model to improve the heat exchange performance and uniformity of the flow-field distribution in the engine compartment of a wheel loader. Flow-field analyses are performed for an XG956 wheel loader in a virtual wind tunnel using the combined engine compartment thermal management model and computational fluid dynamics. The Fluent calculations revealed various problems. For example, the inlet flow rate at both sides of the engine compartment is small, which accounts for about 8.5% of the total flow, and the flow uniformity of radiator becomes worse with the increase in the air flow. The original cooling system is improved based on the simulation results and then verified by field testing. A comparison of the test data with the simulations indicates that the values obtained using the thermal management model of the engine compartment are largely in agreement with the experimental values, with a maximum deviation of the heat transfer rate at the rated speed of 5.1%. The research method presented in this article could further help to increase the productivity of the non-road mobile machinery cooling system and lower design costs. The temperature of pressurized air, hydraulic oil, transmission oil, and engine cooling fluid decreased by 22.5%, 8.7%, 2.2%, and 8.4% in the improved loader, respectively.

scholarly journals Numerical analysis of heat exchange process in the biomass carbonisation reactor

2019 ◽  
Vol 252 ◽  
pp. 05019 ◽  
Author(s):  
Robert Zarzycki ◽  
Justyna Jędras
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Numerical Analysis ◽  
Exchange Process ◽  
Geometrical Model ◽  
Heating Time ◽  
Heating Process ◽  
Hot Air ◽  
Cyclic Operation ◽  
Heat Exchange Process

The study presents the problem of heat exchange in the biomass carbonisation reactor with cyclic operation. Based on the actual parameter of the biomass carbonisation reactor, a geometrical model was developed, and the computation of the heating process was conducted for two cases: an empty reactor and a filled reactor. Its result demonstrated that for the analysed configuration of the reactor, the process of heating biomass in the containers is limited by the capability of heat transfer to the biomass in the container. The results suggest opportunities for the improved heat exchange in the reactor and, accordingly, shortening heating time through installation of the system that forces circulation of hot air inside the reactor.

Flow Field and Temperature Field in GaN-MOCVD Reactor Based on Computational Fluid Dynamics Modeling

2018 ◽  
Vol 35 (9) ◽  
pp. 098101
Author(s):  
Shu-Zhe Mei ◽  
Quan Wang ◽  
Mei-Lan Hao ◽  
Jian-Kai Xu ◽  
Hong-Ling Xiao ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Field ◽  
Flow Field ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Mocvd Reactor

Numerical Investigation on Unsteady Characteristics in Different Rim Seal Geometries: Part A

2020 ◽  
Author(s):  
Xie Lei ◽  
Wang RuoNan ◽  
Liu Guang ◽  
Lian ZengYan ◽  
Du Qiang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Distribution ◽  
Engine Efficiency ◽  
Ansys Cfx ◽  
Geometry Configuration ◽  
Numerical Simulation Methods ◽  
Unsteady Simulation ◽  
Unsteady Characteristics ◽  
Cooling Air

Abstract Secondary sealing flow is of great importance in the turbine disk cooling and sealing system. The amount of cooling air extracted from the compressor is crucial to engine efficiency. To determine a minimum amount of cooling air, the flow characteristic of the rim seal should be investigated. Numerical simulation is carried out to investigate the flow field near the rim seal region. Both RANS and URANS numerical simulation methods are used in the commercial CFD code ANSYS CFX to analyze axial and radial rim seals. In the simulation, a 1/33 sector is selected as computing region to simulate the flow field and the SST turbulent model is used. The steady and unsteady simulation results of pressure distribution and seal efficiency are analyzed and compared. The computed results show that due to the different geometry configuration, the pressure distribution also shows inconsistency. Unsteady phenomena are observed in both axial and radial type of rim seals. Radial sealing lip can suppress the inherent unsteadiness and interaction between main flow and sealing flow, thus showing higher sealing efficiency. Comparing to steady results using the RANS method; unsteady simulation, using the URANS method, can capture the pressure difference and seal efficiency fluctuation at the disk rim more efficiently. Also, the interaction between the rotor and stator is considered in unsteady simulation, so the unsteady simulation is recommended. The results obtained in the current paper are useful to the investigation and design of turbine rim seals.

scholarly journals Numerical Simulation of Temperature and Fluid Fields in Solidification Process of Ferritic Stainless Steel under Vibration Conditions

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 174
Author(s):  
Wenli Wang ◽  
Jing Chen ◽  
Miaomiao Li ◽  
Along Wang ◽  
Mengyao Su
Keyword(s):  
Stainless Steel ◽  
Temperature Field ◽  
Flow Field ◽  
Ferritic Stainless Steel ◽  
Stokes Equations ◽  
Solidification Process ◽  
Crystal Formation ◽  
Positive Temperature ◽  
Vibration Direction ◽  
Casting Mold

A three-dimensional model of a circular casting mold with a vibrating nucleus generator was established, and the characteristics of temperature and flow fields during the solidification process of ferritic stainless steel Cr17 in the casting mold were analyzed using finite element and finite difference methods. A standard k-ε turbulent current model was adopted to simulate the temperature field, and a standard k-ε model in Reynolds-averaged Navier–Stokes equations (RANS) was employed to deal with the flow field. The temperature field diffuses outward with a positive temperature gradient. Low degrees of undercooling can prevent solidified shells from forming rapidly on the surface of the nucleus generator. The temperature perpendicular to the direction of vibration is lower than that in the direction of vibration. The flow field exhibits a heart-shaped distribution and spreads gradually outward. The uniform distribution of grains can be achieved at three different frequencies of vibration. The results show that the degree of undercooling affects the distribution of the temperature field while the frequency of vibration affects the flow field significantly. Under the conditions of undercooling of 540 K and vibration frequency of 1000 Hz, the region perpendicular to the vibration direction of the nucleus generator is the optimum area for equiaxed crystal formation.

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