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.

The Finite Element Analysis of Flow Field and Temperature Field in the Molten Pool of Surface Treatment by Electron Beam

2012 ◽  
Vol 591-593 ◽  
pp. 908-911
Author(s):  
Rong Wang ◽  
Guo Bin Shen ◽  
De Qiang Wei
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Electron Beam ◽  
Liquid Metal ◽  
Flow Field ◽  
Flow Velocity ◽  
Molten Pool ◽  
Driving Forces ◽  
Specimen Thickness ◽  
Beam Spot

A finite element model was established to describe the flow field and temperature field during the surface modification by electron beam in this paper. The driving forces of molten pool were considered in the mode. The flow of liquid metal was different between the inside and outside of the beam spot; the direction of the flow was along the surface to the specimen thickness. When the liquid metal was in the bottom of the pool, it flowed along the bottom to the pool edge. The largest flow velocity was 0.28m/s in the center of the beam spot, the minimum flow velocity was 0.11 m/s in the bottom of molten pool. The temperature of sample is uniform distribution, the temperature distribution show a gradient distribution in cross section.

Numerical Analysis of Dual-Flow Fields in Mini-TBM for Chinese LiPb Experimental Loop Dragon-IV

2010 ◽  
Author(s):  
Wei-hua Wang ◽  
Zhi-qiang Zhu ◽  
Qun-ying Huang ◽  
Xin-zhen Ling ◽  
Jin-ling Li
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Gas Flow ◽  
Flow Fields ◽  
Three Dimensions ◽  
Temperature Fields ◽  
Liquid Lithium ◽  
Flow And Heat Transfer ◽  
Helium Gas ◽  
Joint Contribution

Mini-TBM will be tested in chinese LiPb experimenttal loop Dragon-IV to validate the thermal-hydraulic effect of DFLL-TBM, such as dual-flow fields heat transfer, temperature fields, velocity fields, flux distribution of liquid lithium lead and helium gas. It is difficult to measure the detailed dual-flow fields of liquid metal LiPb and helium gas in mini-TBM. Three dimensions numerical analysis of the LiPb and helium gas flow and heat transfer in Mini-Test Blanket Module (TBM) therefore has been carried out using the CFD code FLUENT. The detailed dual-flow fields, which include temperature, velocity, pressure and heat transfer of liquid LiPb and helium gas, are presented to support for the test of mini-TBM, and to supply more robust database and make a significant joint contribution to the future TBM testing in EAST and ITER, and also optimize and improve the design of DFLL-TBM system for ITER.

scholarly journals THE INFLUENCE OF OPERATIONAL AND STRUCTURAL PARAMETERS ON THE UNEVENNESS OF THE TEMPERATURE FIELD AT THE OUTLET OF THE GAS TURBINE COMBUSTION CHAMBER

2020 ◽  
pp. 80-87
Author(s):  
Ali Sulaiman ◽  
◽  
Bilal Mingazov ◽  
Yury Aleksandrov ◽  
The Nguyen ◽  
...  
Keyword(s):  
Temperature Field ◽  
Combustion Chamber ◽  
Gas Flow ◽  
Structural Parameters ◽  
Temperature Fields ◽  
Mixing Process ◽  
Operational Parameters ◽  
Air Jets ◽  
Annular Jet ◽  
Secondary Air

Ensuring acceptable temperature field non-uniformity at the outlet of the combustion chamber is a very important requirement that determines the reliability and durability of the turbine. The formation of non-uniformity is determined by the nature of the interaction of the secondary air jets with the gas flow in the flame tube and depends on many factors, both structural and operational parameters. In this paper, we propose to evaluate the non-uniformity of the temperature fields at the outlet of the combustion chamber using a mixing coefficient that determines the quality of mixing jets of secondary air with a gas stream in the mixer. Based on the equation of turbulent diffusion during the flow of an annular jet into a limited space, an analytical dependence is obtained in the work that allows one to calculate the mixing process in the combustion chamber. The connection of the mixing process with the formation of temperature fields is established. Based on this, dependences are obtained for calculating the nonuniformity of temperature fields. Their satisfactory agreement with experimental data was shown. The found dependences allow one to analyze the influence of various parameters on the non-uniformity of temperature fields and accelerate the refinement of the combustion chamber by this parameter. The possibility of predicting the effect of various parameters on the unevenness of temperature fields is shown. The presence of the optimal value of the degree of opening of the mixer is confirmed, at which the minimum value of the unevenness of the temperature field at the outlet of the combustion chamber is achieved. Therefore, the analytical relationships found in the work allow optimizing the design of the mixer in the combustion chamber and the distribution of secondary air in it in order to reduce the unevenness of the temperature fields at the outlet of the combustion chamber.

Capturing Nongradient Transport in Nonequilibrium Gas Flow

2008 ◽  
Author(s):  
X. J. Gu ◽  
D. R. Emerson
Keyword(s):  
Temperature Field ◽  
Couette Flow ◽  
Transport Mechanism ◽  
Gas Flow ◽  
Transport Model ◽  
Temperature Fields ◽  
Order Moment ◽  
Nonequilibrium Gas ◽  
The One ◽  
Planar Couette Flow

A higher order moment method is employed to construct the transport model for nonequilibrium gas flow in microscale geometries. The one dimensional planar Couette flow was chosen to demonstrate the significance of capturing the nongradient transport phenomena in the prediction of velocity and temperature fields. For planar Couette flow in the transition regime, the velocity profile is nonlinear and the induced temperature field is no longer parabolic. These features are attributed to the nongradient transport mechanism in a nonequilibrium gas. Furthermore, it is revealed that, for a given temperature field, the gradient transport model overestimates the heat transfer significantly. This, again, can be compensated by the nongradient transport mechanism.

Experimental Study of Humid Air Diffusion Flames in HAT Cycle

2007 ◽  
Author(s):  
Bing Ge ◽  
Shu-Sheng Zang ◽  
Xin Gu
Keyword(s):  
Flow Field ◽  
Flow Region ◽  
Flow Fields ◽  
Temperature Fields ◽  
Reversed Flow ◽  
Humid Air ◽  
Turbulent Diffusion Flame ◽  
Dry Air ◽  
Humid Air Combustion ◽  
Combustion Flow

Combustion with humid air is a key process of humid air turbine (HAT) cycles. Many studies have been undertaken to understand the influence of moisture in air on combustion fields. This study focuses on investigating the differences between the propane/humid air turbulent diffusion flame in a bluff-body burner and the same flame with normal dry air. The moisture levels were achieved by injecting steam into dry air. Particle image velocimetry was used to study the velocity fields experimentally in the humid reactive burner flow and the equivalent non-humid flow. The temperature fields of flames were measured using high temperature thermocouples, and the NO distributions were obtained with gas detection instruments. The results show that although humid air reactive flow fields are similar to the non-humid flow fields in general, there are some differences in the humid air combustion flow field comparing to the same combustion flow field with normal dry air: the center of the reversed-flow region goes forward; the dimension of the reversed-flow region is smaller. An analysis of NO formation revealed NO reduction of humid air flames due to the presence of steam. It is suggested that humid air combustion is helpful to shorten the axial length of combustor, and reduce the formation of pollution.

Comparing 2D and 3D numerical simulation results of gas flow velocity in convection reflow oven

2014 ◽  
Vol 26 (4) ◽  
pp. 223-230 ◽  
Author(s):  
Balázs Illés
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Flow Velocity ◽  
Gas Flow ◽  
Content Type ◽  
Simulation Results ◽  
2D And 3D ◽  
Gas Flow Velocity ◽  
2D Model ◽  
Gas Flow Field

Purpose – This paper aims to compare and study two-dimensional (2D) and three-dimensional (3D) computational fluid dynamics simulation results of gas flow velocity in a convection reflow oven and show the differences of the different modeling aspects. With the spread of finer surface-mounted devices, it is important to understand convection reflow soldering technology more deeply. Design/methodology/approach – Convection reflow ovens are divided into zones. Every zone contains an upper and a lower nozzle-matrix. The gas flow velocity field is one of the most important parameters of the local heat transfer in the oven. It is not possible to examine the gas flow field with classical experimental methods due to the extreme circumstances in the reflow oven. Therefore, numerical simulations are necessary. Findings – The heat transfer changes highly along the moving direction of the assembly, and it is nearly homogeneous along the traverse direction of the zones. The gas flow velocity values of the 2D model are too high due to the geometrical distortions of the 2D model. On the other hand, the calculated flow field of the 2D model is more accurate than in the 3D model due to the finer mesh. Research limitations/implications – Investigating the effects of tall components on a printed wiring board inside the gas flow field and further analysis of the mesh size effect on the models. Practical implications – The presented results can be useful during the design of a simulation study in a reflow oven (or in similar processes). Originality/value – The presented results provide a completely novel approach from the aspect of 2D and 3D simulations of a convection reflow oven. The results also reveal the heat transfer differences.

scholarly journals Effect of Mold Width on the Flow Field in a Slab Continuous-Casting Mold with High-Temperature Velocity Measurement and Numerical Simulation

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1943
Author(s):  
Jian-Qiu Liu ◽  
Jian Yang ◽  
Chao Ma ◽  
Yi Guo ◽  
Wen-Yuan He ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Flow Velocity ◽  
Turbulent Kinetic Energy ◽  
Flow Rate ◽  
Gas Flow ◽  
Immersion Depth ◽  
Gas Flow Rate ◽  
Argon Gas ◽  
Slag Entrainment

In this paper, the effects of the width of the mold on the surface velocity, flow field pattern, turbulent kinetic energy distribution, and surface-level fluctuation in the mold were studied with measurement of the flow velocity near the surface of the mold at high temperature with the rod deflection method and numerical calculation with the standard k-ε model coupled with the discrete-phase model (DPM) model for automobile exposed panel production. Under the conditions of low fixed steel throughput of 2.2 ton/min, a nozzle immersion depth of 140 mm, and an argon gas flow rate of 4 L/min, as the width of the mold increases from 880 mm to 1050 mm and 1300 mm, the flow velocity near the surface of the mold decreases. The flow direction changes from the positive velocity with the mold widths of 880 mm and 1050 mm to the unstable velocity with the mold width of 1300 mm. The calculated results are in good agreement with the measured results. The turbulent kinetic energy near the submerged entry nozzle (SEN) gradually increases, and the risk of slag entrainment increases. Under the conditions of high fixed steel throughput of 3.5 ton/min, the SEN immersion depth of 160 mm, and the argon gas flow rate of 10 L/min, as the width of the mold increases from 1600 mm to 1800 mm and 2000 mm, the velocity near the mold surface decreases. The flow velocity at 1/4 of the surface of the mold is positive with the mold width of 1600 mm, while the velocities are negative with the widths of 1800 mm and 2000 mm. The calculated results are basically consistent with the measured results. The high turbulent kinetic energy area near the nozzle expands to a narrow wall, and the risk of slag entrainment is significantly increased. In both cases of low and high fixed steel throughput, the change rules of the flow field in the mold with the width are basically the same. The argon gas flow rate and the immersion depth of SEN should be adjusted reasonably to optimize the flow field in the mold with different widths under the same fixed steel throughput in the practical production.

Analysis and Improvement on Acoustic Performance of Muffler with the Consideration of Temperature and Flow Velocity

2014 ◽  
Vol 875-877 ◽  
pp. 1143-1147
Author(s):  
Yi Xiang Hu ◽  
Shun Ming Li ◽  
Qing Liu
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Output Power ◽  
Insertion Loss ◽  
Structural Parameters ◽  
Acoustic Fields ◽  
Influence Of Temperature ◽  
Acoustic Performance ◽  
Field Temperature

Aiming for the acoustic performance of expanded-muffler, the acoustic fields, flow field, temperature field and flow regenerated noise inside the expanded-muffler were studied. Furthermore, with the consideration of temperature and flow velocity, the influence of temperature and flow velocity on acoustic performance was obtained. Based on the research, the acoustic performance of an exhaust muffler was studied. By adjusting the structural parameters, without affecting the engine output power, the insertion loss of muffler has average increased by 5.1 dB (A).

Numerical model of A.C. glow discharge plasma anemometer via the coupling of gas flow and plasma model

2018 ◽  
Vol 81 (3) ◽  
pp. 30801
Author(s):  
Bing Yu ◽  
Pei Yuan ◽  
Enyu Shen ◽  
Huaxu Shen
Keyword(s):  
Flow Field ◽  
Density Distribution ◽  
Flow Velocity ◽  
Gas Flow ◽  
Field Model ◽  
Supply Voltage ◽  
Fluid Model ◽  
Glow Discharge Plasma ◽  
Electrode Spacing ◽  
Plasma Model

A new approach to build the numerical modeling of AC (alternating current) plasma anemometer is proposed. Firstly, the plasma model and gas flow model utilized in the proposed method are introduced. The plasma model (xpdp2) is built by PIC/MCC modeling method, while gas flow field model is the fluid model. By combining the flow field model and plasma model, the proposed anemometer model could be obtained. Then the effects of flow velocity on the ion density distribution, electron density distribution and electric potential distribution are studied from micro perspective, and the results show that charged particles move towards the direction of flow velocity. Another facts can also be observed, the movement of electron is not obvious, and flow velocity has no effect on the electronic potential. Finally, the effects of supply voltage, discharge frequency and electrode spacing on the discharge characteristics are investigated from macro perspective, and the results show that there is a nearly linear relationship between flow velocity and gap voltage, which indicate that the plasma anemometer could be applied for flow velocity measurement. The simulation result shows that linear relationships are pretty good when the frequencies are 2 MHz and 3.65 MHz. In addition, the result also shows that, within our chosen distance, small spacing is more suitable for high frequency plasma anemometer.

Electrode Arrangement Effect on Natural Convection in a Horizontal Enclosure

2009 ◽  
Author(s):  
R. Ghazi ◽  
M. S. Saidi ◽  
M. H. Saidi
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Field ◽  
Natural Convection ◽  
Flow Field ◽  
Electric Field ◽  
Heat Transfer Enhancement ◽  
Temperature Fields ◽  
Transfer Enhancement ◽  
Rayleigh Numbers

The heat transfer enhancement of natural convection, using electrohydrodynamic technique inside a horizontal enclosure heated from below, is studied numerically. The interactions between electric field, flow field, and temperature field are investigated by CFD methods. The flow and temperature fields are affected by voltage applied at the wire electrodes. For different voltages and number of electrodes, it is noticed that the Nusselt number increased in all cases and the best enhancement is obtained at lower Rayleigh numbers. It is also shown that increasing the number of electrodes doesn’t always cause an increase in the heat transfer enhancement. Actually, when the number of electrodes is equal to the number of Be´nard cells, the best heat transfer enhancement is obtained.

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