Effect of Latent Heat Related to Solidification Kinetics on Heat Transfer during Solidification of Al Alloy

2014 ◽  
Vol 884-885 ◽  
pp. 273-276
Author(s):  
Seok Jae Lee
Keyword(s):  
Heat Transfer ◽  
Latent Heat ◽  
Temperature Compensation ◽  
Solid Phase ◽  
A356 Alloy ◽  
Cooling Curve ◽  
Al Alloy ◽  
Cooling Curves ◽  
Solidification Kinetics ◽  
Heat Transfer Simulation

The effect of the latent heat related to the rate of the solidification kinetics during solidification was investigated by using the heat transfer simulation. The latent heat was generated proportional to the amount of the fraction of transformed solid phase and directly affected the temperature compensation during solidification. The importance of the solidification kinetics was discussed by comparing cooling curves calculated using different solidification kinetics with experimentally measured cooling curve of A356 alloy.

A Comparison of Input Data Used to Represent Phase Transformations during the Quenching of a Large Nuclear Forging

2016 ◽  
Vol 716 ◽  
pp. 555-565
Author(s):  
Michael P. Howson ◽  
Bradley P. Wynne ◽  
Peter S. Davies ◽  
Sinan S. Al-Bermani ◽  
Jesus Talamantes-Silva
Keyword(s):  
Specific Heat ◽  
Latent Heat ◽  
Lower Bainite ◽  
Cooling Curve ◽  
Model Parameters ◽  
Cooling Curves ◽  
Scanning Calorimetry ◽  
Effective Specific Heat ◽  
Input Variables ◽  
Predictive Software

The present work explores the importance of model parameters and input variables when simulating the quenching of thick sectioned nuclear forgings. The modelling approach adopted uses values of specific heat capacity, containing latent heat release, to simulate cooling curves; rather than calculating transformation kinetics based upon a mathematical model. Termed the effective specific heat (Cpeff), two different methods were used to establish values: differential scanning calorimetry (DSC) and thermos dynamic predictive software. Values were then included in finite element (FE) models to simulate the characteristic cooling at the mid-wall position in a thick section forging and were validated against production thermocouple data. The investigation found that the formation of ferrite, bainite and martensite or lower bainite were all represented by the data established using DSC and critical formation temperatures were comparable with others in the literature. Conversely, values calculated using the thermodynamic software failed to represent ferrite formation and predicted different critical transformation temperatures for bainite. The simulated cooling curve that used the software predicted Cpeff data was comparable to the thermocouple data either side of the bainite transformation, however during the transformation the effects of latent heat on cooling rate were over predicting leading to disparities. The equivalent DSC cooling curves produced a near exact match.

Thermal and Kinetic Analysis of the solidification of a near eutectic Al-Cu Alloy

2014 ◽  
Vol 1611 ◽  
pp. 105-110
Author(s):  
M. Morua ◽  
M. Ramirez-Argaez ◽  
C. Gonzalez-Rivera
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Kinetic Analysis ◽  
Eutectic Growth ◽  
Eutectic Solidification ◽  
Cooling Curves ◽  
Transfer Coefficients ◽  
Fourier Thermal Analysis ◽  
Cu Alloy ◽  
Solidification Kinetics

ABSTRACTIn this work the thermal and kinetic analysis of the cooling and solidification of a near eutectic Al-Cu alloy is performed using inverse thermal and solidification kinetics analysis. The Fourier thermal analysis is applied to experimental cooling curves to obtain data on solid fraction evolution and latent heat of solidification. Inverse thermal analysis is applied to calculate the global heat transfer coefficients that allow correct simulation of the cooling of experimental probes. The free growth method is used to obtain the eutectic growth coefficients. All the obtained parameters are feed into a heat transfer-solidification kinetics model to validate the methodology and results generated from this work. It is found a relatively good agreement between experimental and predicted cooling curves which suggest that this methodology could be used to generate useful information needed to simulate eutectic solidification.

On the characterization of eutectic grain growth during solidification

2012 ◽  
Vol 1485 ◽  
pp. 161-166
Author(s):  
M. Morua ◽  
M. Ramirez-Argaez ◽  
C. Gonzalez-Rivera
Keyword(s):  
Heat Transfer ◽  
Cast Iron ◽  
Kinetic Parameters ◽  
Grain Growth ◽  
Eutectic Solidification ◽  
Cooling Curves ◽  
Density Data ◽  
Solidification Kinetics ◽  
Grain Growth Kinetics

ABSTRACTThe purpose of this work is to compare the results obtained from three methodologies intended to estimate kinetic parameters describing quantitatively the grain growth during equiaxed eutectic solidification in order to identify the best procedure to characterize grain growth kinetics. A heat transfer / solidification kinetics model is implemented to simulate the cooling and solidification of eutectic Al-Si and eutectic cast iron in sand molds. Using simulated cooling curves and volume grain density data generated by the model, the three methods are applied to obtain their predicted grain growth coefficients. The predicted results are compared with the grain growth coefficients used in the model. The outcome of this work suggests that two of the three methods under study represent the best option to obtain the kinetic parameters of equiaxed growth during eutectic solidification.

Macro-Micro Modeling and Simulation of Solidification Kinetics of Pb-Sn Alloys

2006 ◽  
Vol 509 ◽  
pp. 171-176
Author(s):  
L. López ◽  
H. Cruz ◽  
B. Campillo ◽  
Carlos González-Rivera
Keyword(s):  
Heat Transfer ◽  
Solidification Rate ◽  
Primary Phase ◽  
Experimental Results ◽  
Eutectic Solidification ◽  
Cooling Curves ◽  
Solidification Kinetics ◽  
Eutectic Morphology ◽  
Micro Modeling ◽  
Kinetics Of

The purpose of this work is to explore the effect of the presence of two different primary phases on the microstructure and solidification kinetics of Pb-Sn alloys. The experimental results have been compared with predictions obtained from the Newton Thermal Analysis of cooling curves generated by a conventional heat transfer-solidification kinetics model. Three Pb-Sn alloys have been considered in this work in order to explore the solidification characteristics of the eutectic in hypoeutectic, hypereutectic and eutectic compositions. Experimental results indicate that the Pb-Sn eutectic morphology and the solidification rate depend on the nature of the pre-existent primary phase during eutectic solidification. From the observed discrepancies between experimental and simulated results it is concluded that further improvements are needed to simulate the solidification kinetics of eutectic microconstituents in the presence of pre-existing primary phases.

scholarly journals Cooling Curve Analysis Method using a Simplified Energy Balance

2018 ◽  
Vol 3 (1) ◽  
pp. 383
Author(s):  
C. González Rivera ◽  
A. Amaro Villeda ◽  
M. Ramírez Argáez
Keyword(s):  
Energy Balance ◽  
Latent Heat ◽  
Curve Analysis ◽  
Phase Changes ◽  
Cooling Curve ◽  
Analysis Method ◽  
Cooling Process ◽  
Solidification Kinetics ◽  
Cooling Curve Analysis ◽  
Metallic Sample

In this work is described a new cooling curve analysis method focused on the experimental determination of the latent heat of phase changes and phase transformation kinetics.The method analyses the cooling process of a metallic sample, initially liquid that is contained into a cylindrical metallic mold, both of known weight, thermally isolated at its top and bottom. The method is based on a simplified energy balance associated with the experimental measurement of the temperature change of the sample during its cooling process. The method was applied experimentally to zinc and tin of commercial purity, initially liquids and contained into stainless steel molds in order to determine its ability to determine the latent heat of solidification. In order to validate the method, the obtained values of latent heat were compared with the values reported in thermochemical databases. The obtained results suggest that this method can be used to characterize the solidification of metals..Keywords: Solidification, Kinetics; Cooling curve analysis.

scholarly journals Effect of Agitation, Temperature, and Quenching Medium on Cooling Curve and cooling rate for Steels

2018 ◽  
Vol 21 (4) ◽  
pp. 473-478
Author(s):  
Hala S. Hasan ◽  
Reham H. Khaleefah ◽  
Nasser A. Al haboubi ◽  
Raad D. Salman
Keyword(s):  
Heat Transfer ◽  
Steel Sample ◽  
Cooling Curve ◽  
Temperature History ◽  
Stainless Steel Sample ◽  
Cooling Curves ◽  
Ability To Work ◽  
Cooling Stage ◽  
Quenching Process ◽  
Transfer Properties

The control of quenching process has been investigated in this study by developing a quench system design to simulate the quenching process and measure the time – temperature history inside the sample during the cooling stage. The main purpose of this quench system is to evaluate the quench power of different quenchant at different conditions (type, temperature and agitation).A stainless steel sample was used with a suitable measurement as a probe in designing this quench system.The performance of two of quenchants (water and brine) with different conditions was investigated, and the designed probe was used to illustrate the effect of quenching parameters (quenchant type, temperature and its agitation) on cooling curves and cooling rate.The quenching system has proven its ability to work effectively and the results showed that heat transfer properties were significantly affected by quenchant parameters.

Heat Exchanger Performance in Latent Heat Thermal Energy Storage

1980 ◽  
Vol 102 (2) ◽  
pp. 112-118 ◽  
Author(s):  
R. N. Smith ◽  
T. E. Ebersole ◽  
F. P. Griffin
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Solid Phase ◽  
Storage System ◽  
Temperature Drop ◽  
Heat Of Fusion ◽  
Analytical Prediction

An experimental study was made of the heat transfer in a component of a low temperature thermal energy storage system using latent heat of fusion of a phase change material (PCM). Measurements were made of the temperature rise of water flowing in a channel adjacent to a container filled with a freezing PCM, Gulfwax 33. In addition, temperature measurements within the PCM provided the location of the liquid/solid interface as a function of time. A simple analytical prediction is compared with the data to provide a verification of the qualitative observations. Certain multidimensional effects which occur during the freezing (discharge) mode of operation are identified especially the enhancement of freezing rates when the PCM container sidewalls (those not in contact with the heat exhange fluid) are conducting and are closely spaced. One limitation to storage systems of this type is the resistance to heat transfer of the solid phase, requiring a significant temperature drop for acceptable discharge rates. The additional “heat path” provided by the conducting container walls is shown to significantly reduce this resistance. Some observations concerning the implications for design of actual storage components are also provided.

Cooling Curve Analysis of A356 Alloy by Conventional Casting and the Effect of Stirring

2022 ◽  
Vol 327 ◽  
pp. 300-305
Author(s):  
Gerardo Sanjuan-Sanjuan ◽  
Ángel Enrique Chavez-Castellanos
Keyword(s):  
Eutectic Reaction ◽  
A356 Alloy ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Resistance Furnace ◽  
Globular Structure ◽  
Second Derivatives ◽  
Cooling Curve Analysis ◽  
Aluminum A356 Alloy ◽  
Electrical Resistance Furnace

The present investigation attempted to explore the effect of stirring during solidification of Aluminum A356 alloy, mainly focusing on the change from dendrite to globular structure. For this purpose samples of A356 alloy were melted in the electrical resistance furnace and cooling curves were recorded for each level agitation. The experimental curves were numerically processed by calculating first and second derivatives. From these were determined temperatures and times of start nucleation of alpha solid and eutectic reaction.

CONTRIBUTION OF LATENT HEAT TRANSFER IN POOL BOILING

2018 ◽  
Author(s):  
Takanori Tanaka ◽  
Tomohide Yabuki ◽  
Koji Miyazaki
Keyword(s):  
Heat Transfer ◽  
Latent Heat ◽  
Pool Boiling
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