The Effect of Droplet Impingement on Pressure and Heat Flux Distributions on Molten Pool in GMAW-Based Rapid Forming

2014 ◽  
Vol 494-495 ◽  
pp. 391-394
Author(s):  
Feng Liang Yin ◽  
Sheng Zhu ◽  
Jian Liu ◽  
Xiao Ming Wang ◽  
Lei Guo
Keyword(s):  
Heat Flux ◽  
Numerical Model ◽  
Molten Pool ◽  
Flux Distribution ◽  
Three Dimensional ◽  
Heat Flux Distribution ◽  
Droplet Impingement ◽  
Dimensional Precision ◽  
Low Dimensional

A low dimensional precision is one of drawback for the GMAW-based rapid forming technique, which is related to pressure and heat flux on molten pool. To study pressure and heat flux on molten pool, the effect of droplet impinging process must been considered. A three-dimensional numerical model was built to analysis pressure and heat flux distribution on molten pool. Solving the model, it was found that pressure on the cathode by the arc decreases dramatically when the droplet is coming. As to heat flux, the appearance of droplet cuts down it within about 1.5 mm away from arc axial. Out of 1.5 mm away from arc axial, droplets effect on heat flux is not obvious.

EMC3-EIRENE simulations of neon impurity seeding effects on heat flux distribution on CFETR

2022 ◽  
Author(s):  
Shuyu Dai ◽  
Defeng Kong ◽  
Vincent Chan ◽  
Liang Wang ◽  
Yuhe Feng ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Load ◽  
Flux Distribution ◽  
Three Dimensional ◽  
Input Power ◽  
Heat Flux Distribution ◽  
Maximum Heat ◽  
Maximum Heat Flux ◽  
Heat Loads ◽  
Injection Location

Abstract The numerical modelling of the heat flux distribution with neon impurity seeding on CFETR has been performed by the three-dimensional (3D) edge transport code EMC3-EIRENE. The maximum heat flux on divertor targets is about 18 MW m-2 without impurity seeding under the input power of 200 MW entering into the scrape-off layer. In order to mitigate the heat loads below 10 MW m-2, neon impurity seeded at different poloidal positions has been investigated to understand the properties of impurity concentration and heat load distributions for a single toroidal injection location. The majority of the studied neon injections gives rise to a toroidally asymmetric profile of heat load deposition on the in- or out-board divertor targets. The heat loads cannot be reduced below 10 MW m-2 along the whole torus for a single toroidal injection location. In order to achieve the heat load mitigation (<10 MW m-2) along the entire torus, modelling of sole and simultaneous multi-toroidal neon injections near the in- and out-board strike points has been stimulated, which indicates that the simultaneous multi-toroidal neon injections show a better heat flux mitigation on both in- and out-board divertor targets. The maximum heat flux can be reduced below 7 MWm-2 on divertor targets for the studied scenarios of the simultaneous multi-toroidal neon injections.

LIVE Experiments on Melt Behavior in the RPV Lower Head

2008 ◽  
Author(s):  
Alexei Miassoedov ◽  
Thomas Cron ◽  
Jerzy Foit ◽  
Xiaoyang Gaus-Liu ◽  
Silke Schmidt-Stiefel ◽  
...  
Keyword(s):  
Heat Flux ◽  
Molten Pool ◽  
Vessel Wall ◽  
Flux Distribution ◽  
Severe Accident ◽  
Experimental Program ◽  
Strong Impact ◽  
Residual Water ◽  
Heat Flux Distribution ◽  
Lower Head

Behavior of the corium pool in the lower head is still a critical issue in understanding of PWR core meltdown accidents. One of the key parameter for assessing the vessel mechanical strength is the resulting heat flux at the pool-vessel interface. A number of studies [1]–[3] have already been performed to pursue the understanding of a severe accident with core melting, its course, major critical phases and timing and the influence of these processes on the accident progression. Uncertainties in modeling these phenomena and in the application to reactor scale will undoubtedly persist. These include e.g. formation and growth of the in-core melt pool, relocation of molten material after the failure of the surrounding crust, characteristics of corium arrival in residual water in the lower head, corium stratifications in the lower head after the debris re-melting [4]. These phenomena have a strong impact on a potential termination of a severe accident. The main objective of the LIVE program [5] at FZK is to study the core melt phenomena both experimentally in large-scale 3D geometry and in supporting separate-effects tests, and analytically using CFD codes in order to provide a reasonable estimate of the remaining uncertainty band under the aspect of safety assessment. Within the LIVE experimental program several tests have been performed with water and with non-eutectic melts (mixture of KNO3 and NaNO3) as simulant fluids. The results of these experiments, performed in nearly adiabatic and in isothermal conditions, allow a direct comparison with findings obtained earlier in other experimental programs (SIMECO, ACOPO, BALI, etc.) and will be used for the assessment of the correlations derived for the molten pool behavior. The information obtained from the LIVE experiments includes heat flux distribution through the reactor pressure vessel wall in transient and steady state conditions, crust growth velocity and dependence of the crust formation on the heat flux distribution through the vessel wall. Supporting post-test analysis contributes to characterization of solidification processes of binary non-eutectic melts. Complimentary to other international programs with real corium melts, the results of the LIVE activities provide data for a better understanding of in-core corium pool behavior. The experimental results are being used for development of mechanistic models to describe the in-core molten pool behavior and their implementation in the severe accident codes like ASTEC. The paper summarizes the objectives of the LIVE program and presents the main results obtained in the LIVE experiments up to now.

Determination of Outside Heating Distribution Using an Inverse Algorithm for an Industry Hydrothermal Autoclave With Three-Dimensional Flows

2004 ◽  
Author(s):  
Hongmin Li ◽  
Minel J. Braun ◽  
G.-X. Wang ◽  
Edward A. Evans
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Flow ◽  
Heat Conduction ◽  
Flux Distribution ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Heat Flux Distribution ◽  
Inverse Algorithm ◽  
Small Magnitude

Hydrothermal growth is the industry method of preference to obtain high quality single crystals. Due to the high pressure and high temperature growth conditions, growth process is carried out in closed containers. During a growth run, the only flow and heat transfer that control crystal growers have is the outside heating. An inverse algorithm, used to obtain the heating distribution for an autoclave with a two-dimensional flow, is further developed and used to determine the heating distribution for an industry autoclave with three-dimensional flows. A cross-section area average temperature distribution is set as a target. With the three steps, including CFD simulation of the fluid flow, heat conduction in the metal wall, and heat conduction in the insulation layer, the heater heat flux distribution is determined. The distributions appear close to linear from the median height to the top/bottom with small magnitude deviation in the circumferential direction. Linearly distributed heaters, based on the determined heat flux distribution, are then used and heat transfer and fluid flow is numerically simulated with a conjugate model. The achieved temperature agrees well with the targeted one. The distribution and heating rates of linearly distributed heaters can be applied to industry autoclaves.

Boundary Optimal Control of Natural Convection by Means of Mode Reduction

2000 ◽  
Vol 124 (1) ◽  
pp. 47-54 ◽  
Author(s):  
H. M. Park ◽  
W. J. Lee
Keyword(s):  
Optimal Control ◽  
Heat Flux ◽  
Natural Convection ◽  
Gradient Method ◽  
Flux Distribution ◽  
Boussinesq Equation ◽  
Heat Flux Distribution ◽  
Projected Gradient Method ◽  
Galerkin Procedure ◽  
Low Dimensional

We consider problems of controlling the intensity of the Rayleigh-Be´nard convection by adjusting the heat flux distribution at the boundary while keeping the heat input the same. The Karhunen-Loe`ve Galerkin procedure is used to reduce the Boussinesq equation to a low dimensional dynamic model, which in turn is employed in a projected gradient method to yield the optimal heat flux distribution. The performance of the Karhunen-Loe`ve Galerkin procedure is assessed in comparison with the traditional technique employing the Boussinesq equation, and is found to be very accurate as well as efficient.

scholarly journals Analysis of Heat Flux Distribution during Brush Seal Rubbing Using CFD with Porous Media Approach

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1888
Author(s):  
Manuel Hildebrandt ◽  
Corina Schwitzke ◽  
Hans-Jörg Bauer
Keyword(s):  
Heat Flux ◽  
Flux Distribution ◽  
Input Parameter ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Heat Flux Distribution ◽  
Test Rig ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Brush Seal

This paper discusses the question of heat flux distribution between bristle package and rotor during a rubbing event. A three-dimensional Computational Fluid Dynamics (3D CFD) model of the brush seal test rig installed at the Institute of Thermal Turbomachinery (ITS) was created. The bristle package is modelled as a porous medium with local non-thermal equilibrium. The model is used to numerically recalculate experimentally conducted rub tests on the ITS test rig. The experimentally determined total frictional power loss serves as an input parameter to the numerical calculation. By means of statistical evaluation methods, the ma in influences on the heat flux distribution and the maximum temperature in the frictional contact are determined. The heat conductivity of the rotor material, the heat transfer coefficients at the bristles and the rubbing surface were identified as the dominant factors.

scholarly journals A Review of Research on Turbomachinery at MIT Traceable to Support From Mel Hartmann

1993 ◽  
Author(s):  
Jack L. Kerrebrock
Keyword(s):  
Heat Flux ◽  
Transonic Flow ◽  
Flux Distribution ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Faculty Members ◽  
Heat Flux Distribution ◽  
Detailed Understanding ◽  
Support Of Research

Research conducted at MIT since 1968 stemming from early initiatives on the Blowdown Compressor Experiment and on transonic three dimensional CFD, is reviewed from the viewpoint of the consequences of enlightened support of research by exceptionally capable leaders of government research. Among the consequences in this case are development of detailed understanding of the unsteady flows in transonic compressors and their contribution to losses, and the ability to compute the three-dimensional transonic flow in such machines. Analogous results for turbines include the ability to measure and compute the unsteady heat flux distribution on turbine blades and vanes as well as the flow field. In addition to these research results, the programs which are traceable to Mel Hartmann’s early support have produced more than seven faculty members who continue to teach and conduct research in aircraft propulsion and closely related fields, and a corresponding number of students.

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