Using the jominy end-quench test for validation of thermo-metallurgical model parameters

2004 ◽  
Vol 120 ◽  
pp. 571-579
Author(s):  
M. Hunkel ◽  
Th. Lübben ◽  
F. Hoffmann ◽  
P. Mayr
Keyword(s):  
Heat Transfer ◽  
Model Parameters ◽  
Simulation Testing ◽  
Peripheral Surface ◽  
Quench Test ◽  
Good Agreement

One of the most popular tests to determine the hardenability of steels is the Jominy-End-Quench-Test. Moreover this test is useful for simulation testing, too. In this paper the determination of heat transfer fluxes over the quenched surface as well as over the peripheral surface is described. The result is used for simulations of the Jominy-End-Quench-Test for two melts of SAE 52100 (100 Cr 6). One of these was taken from literature, one was used for experiments in IWT. Though transformation behaviors differ in an extreme way, the Jominy-End-Quench-Test can be simulated for both steels with good agreement between simulation and measurement.

scholarly journals Analysis of Heat Transfer through a Protective Clothing Package

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Paulina Gilewicz ◽  
Damian Obidowski ◽  
Krzysztof Sobczak ◽  
Iwona Frydrych ◽  
Agnieszka Cichocka
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Protective Clothing ◽  
Microscopic Level ◽  
Homogeneous Distribution ◽  
Model Parameters ◽  
High Quality ◽  
Measurement Results ◽  
Good Agreement

Abstract The protective clothing packages, which protect the human body against hot factors in a foundry are in continuous development to increase their resistance and comfort of use. The problem of heat transfer through textiles is the active field of research and reliable numerical modeling of this process can be helpful to design high-quality protective products. Therefore, the numerical model of heat transfer through the package based on the aluminized basalt fabric was developed. The macroscopic geometry of weft and warp threads was reproduced in agreement with samples of plain weave basalt fabric. Mapping the stochastically distributed individual monofilaments in basalt threads, as well as modeling the heat transfer between them, was impossible at the microscopic level. Therefore, the weft and warp threads were modeled as a porous material with a homogeneous distribution of basalt and air in their structure. Data from measurements of the bare and aluminized basalt fabrics by the Alambeta device were used to determine the model parameters. The model was used to simulate the heat transfer through the protective package composed of the aluminized basalt fabric, wool clothing, and cotton underwear. A good agreement of model results was found for measurement results in such a package. The presented procedure allowed for the determination of the main thermal properties of tested basalt fabrics.

Device Modeling of a-Si:H Alloy Solar Cells: Calibration Procedure for Determination of Model Input Parameters

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Zeman ◽  
R.A.C.M.M. Van Swaaij ◽  
E. Schroten ◽  
L.L.A. Vosteen ◽  
J.W. Metselaar
Keyword(s):  
Solar Cell ◽  
Material Properties ◽  
Calibration Procedure ◽  
Model Parameters ◽  
Model Input ◽  
A Value ◽  
Input Parameters ◽  
Simulated Material ◽  
Good Agreement

ABSTRACTA calibration procedure for determining the model input parameters of standard a-Si:H layers, which comprise a single junction a-Si:H solar cell, is presented. The calibration procedure consists of: i) deposition of the separate layers, ii) measurement of the material properties, iii) fitting the model parameters to match the measured properties, iv) simulation of test devices and comparison with experimental results. The inverse modeling procedure was used to extract values of the most influential model parameters by fitting the simulated material properties to the measured ones. In case of doped layers the extracted values of the characteristic energies of exponentially decaying tail states are much higher than the values reported in literature. Using the extracted values of model parameters a good agreement between the measured and calculated characteristics of a reference solar cell was reached. The presented procedure could not solve directly an important issue concerning a value of the mobility gap in a-Si:H alloys.

Quartz-Fiber Thermal Insulation: Infrared Radiative Properties and Calculation of Radiative-Conductive Heat Transfer

1996 ◽  
Vol 118 (2) ◽  
pp. 408-414 ◽  
Author(s):  
L. A. Dombrovsky
Keyword(s):  
Heat Transfer ◽  
Disperse Material ◽  
Conductive Heat Transfer ◽  
Radiative Properties ◽  
Conductive Heat ◽  
Radiation Diffusion ◽  
Fiber Thermal Insulation ◽  
Good Agreement ◽  
Scattering And Radiation

Calculations of absorption, transport scattering, and radiation diffusion coefficients for a highly porous material of quartz fibers are performed by use of rigorous scattering theory for arbitrarily oriented cylinders. New results concerning resonance absorption in the semitransparency region and intensive “scattering by absorption” at refractive index n ≈ 1 in the opacity region are obtained. Numerical results for the radiation diffusion coefficient from a theoretical model without taking into account both dependent scattering and interference effects are in a good agreement with the experimental data for isotropic fibrous material of density 144 kg/m3. Calculations allow us to give practical proposals to simplify the determination of optical properties of poly disperse material with randomly oriented fibers. Some results on the radiative–conductive heat transfer in the material considered are presented. The radiation transfer is described in the P1 approximation. A two-band spectral model with bands corresponding to semitransparency and opacity regions is proposed. Applicability of a modified radiative conduction approximation both to transient and to steady-state calculations is discussed.

Heat Transfer in Turbulent Pipe Flow With Optically Thin Radiation

1969 ◽  
Vol 91 (3) ◽  
pp. 330-335 ◽  
Author(s):  
C. S. Landram ◽  
R. Greif ◽  
I. S. Habib
Keyword(s):  
Heat Transfer ◽  
Circular Tube ◽  
Constant Heat Flux ◽  
Turbulent Pipe Flow ◽  
Radiation Problem ◽  
Constant Heat ◽  
Nusselt Numbers ◽  
Fully Developed Turbulent Flow ◽  
Good Agreement

The problem considered is the determination of the heat transfer in fully developed turbulent flow of a radiating optically thin gas in a circular tube. The radiation problem is formulated in terms of the Planck mean and the modified Planck mean coefficients and the temperature profiles and Nusselt numbers have been determined. It is shown that the simple constant shear, constant heat flux formulation yields results that are in very good agreement with more complex calculations.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

The Determination of Forced-Convection Surface-Boiling Heat Transfer

1964 ◽  
Vol 86 (3) ◽  
pp. 365-372 ◽  
Author(s):  
A. E. Bergles ◽  
W. M. Rohsenow
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Experimental Results ◽  
Boiling Curve ◽  
Wall Superheat ◽  
Good Agreement

The characteristics of the boiling curve for forced-convection surface boiling are examined in detail. In the region of low wall superheat, the heat transfer can be predicted by available correlations for forced convection. An analysis is presented for the inception of first significant boiling. Experimental results are in good agreement with analytical predictions. Pool-boiling data were taken under saturated and subcooled conditions for surfaces similar to those used in forced-convection surface boiling. These data indicate that the curves for forced-convection surface boiling cannot be based on data for saturated pool boiling but must rather be based on actual forced-convection data.

scholarly journals Modeling of pure components high pressures densities using CK-SAFT and PC-SAFT equations

2018 ◽  
Vol 83 (3) ◽  
pp. 331-343
Author(s):  
Jovana Ilic-Pajic ◽  
Mirko Stijepovic ◽  
Gorica Ivanis ◽  
Ivona Radovic ◽  
Jasna Stajic-Trosic ◽  
...  
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Model Parameters ◽  
Calculated Density ◽  
Average Percentage ◽  
Pure Compounds ◽  
Density Values ◽  
Temperature And Pressure ◽  
Good Agreement

SAFT equations of state have been widely used for the determination of different thermo-physical and phase equilibria properties. In order to use these equations as predictive models it is necessary to calculate the model parameters. In this work CK-SAFT and PC-SAFT equations of state were applied for the correlation of pure compounds densities in the wide ranges of temperature and pressure (288.15?413.15 K and 0.1?60 MPa, respectively). The calculations of densities for n-hexane, n-heptane, n-octane, toluene, dichloromethane and ethanol, under high pressure conditions, were performed with the new sets of parameters determined in this paper by CK-SAFT and PC-SAFT. Very good agreement between experimental and calculated density values was achieved, having absolute average percentage deviations lower than 0.5 %.

scholarly journals Compact Thermal Model of the Pulse Transformer Taking into Account Nonlinearity of Heat Transfer

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2766 ◽  
Author(s):  
Krzysztof Górecki ◽  
Kalina Detka ◽  
Krzysztof Górski
Keyword(s):  
Heat Transfer ◽  
Thermal Model ◽  
Pulse Transformer ◽  
Model Parameters ◽  
Electric Network ◽  
Self Heating ◽  
The Core ◽  
Proposed Model ◽  
Component Temperature ◽  
Good Agreement

This paper presents a compact nonlinear thermal model of pulse transformers. The proposed model takes into account differentiation in values of the temperatures of a ferromagnetic core and each winding. The model is formulated in the form of an electric network realising electrothermal analogy. It consists of current sources representing power dissipated in the core and in each of the windings, capacitors representing thermal capacitances and controlled current sources modelling the influence of dissipated power on the thermal resistances in the proposed model. Both self-heating phenomena in each component of the transformer and mutual thermal couplings between each pair of these components are taken into account. A description of the elaborated model is presented, and the process to estimate the model parameters is proposed. The proposed model was verified experimentally for different transformers. Good agreement between the calculated and measured waveforms of each component temperature of the tested pulse transformers was obtained. Differences between the results of measurements and calculations did not exceed 9% for transformers with a toroidal core and 13% for planar transformers.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

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