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.

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.

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.

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.

Analysis of Temperatures in Sawing of Granite Based on Parabolic Heat Distribution

2013 ◽  
Vol 589-590 ◽  
pp. 184-187
Author(s):  
Yu Xiang Zhang ◽  
Cong Fu Fang ◽  
Guo Qin Huang ◽  
Yi Qing Yu ◽  
Xi Peng Xu
Keyword(s):  
Heat Flux ◽  
Contact Zone ◽  
Flux Distribution ◽  
Maximum Temperature ◽  
Triangular Distribution ◽  
Heat Distribution ◽  
Temperature Model ◽  
Heat Flux Distribution ◽  
Parabolic Distribution ◽  
Location Point

A temperature model was advanced based on a parabolic heat flux distribution in sawing contact zone in the present paper. It is found that the maximum temperature for parabolic distribution is more higher than that for triangular distribution in the sawing contact zone, and the location point of the maximum temperature for parabolic distribution in the sawing contact zone is much nearer the entrance than that for triangular distribution.

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.

Telemetric Measurement of Heat Transfer Coefficients in Gaseous Flow: First Test of a Recent Sensor Concept in a Rotating Application

2014 ◽  
Author(s):  
Benjamin Heinschke ◽  
Wieland Uffrecht ◽  
André Günther ◽  
Stefan Odenbach ◽  
Volker Caspary
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Gas Turbines ◽  
Flow Path ◽  
Telemetry System ◽  
Test Rig ◽  
Transfer Coefficients ◽  
Gaseous Flow ◽  
Heat Transfer Coefficients ◽  
Telemetric Measurement

Heat transfer coefficients are very important for the design of the various flow paths found in turbomachinery. An accurate measurement of heat transfer is difficult for circumstances of gaseous flow in combination with good thermal conductivity of the boundaries along the flow path. The majority of the measurement methods applied frequently have at least one of the following problems: (1) the measurement system as for instance a heat flux sensor is a thermal barrier in the object of interest, and (2) the sensor introduces for measurement reasons a lot of heat into the object of interest. In both cases the main error results from the modification of the system, which is critical for the investigation of any kind of flow influenced by buoyancy. Furthermore, insufficient fluid reference temperature and/or heat flux with changing sign corrupts any attempt to calculate reliable heat transfer coefficients. The measurement of heat transfer coefficients becomes even more complicated if the flow path of interest rotates at some thousand rpm as for instance in gas turbines or any other fast rotating machine with fluid flow. This contribution presents a new test rig and an experimental investigation of a setup for the direct telemetric measurement of local heat transfer coefficients in gaseous flow with metallic boundaries. The test rig has a complex instrumentation and the measurements are transferred from the rotating to the stationary frame via newly in house developed telemetry system. The measurements presented are based on a recent measurement/sensor concept tested for the first time in the rotating frame. The measurement setup features miniaturized sensor dimensions and low energy consumption. Therefore, the sensor concept is very well suited for use with telemetry system as necessary for many turbomachinery research applications. Furthermore, measurements of the radial distribution of the heat transfer coefficient of a rotating free disc are presented. Additionally a comparison with correlations found in literature as well as a discussion of the results is included.

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