Analytical Model for Heat Transfer Phenomena in Cup-Cast Method

2006 ◽  
Vol 116-117 ◽  
pp. 569-572
Author(s):  
Farshid Pahlevani ◽  
J. Yaokawa ◽  
M. Itamura ◽  
M. Kikuchi ◽  
O. Nagasawa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
A356 Alloy ◽  
Nucleation And Growth ◽  
Heat Transfer Model ◽  
Solid Particles ◽  
Transfer Model ◽  
Heat Transfer Phenomenon ◽  
Semi Solid ◽  
Slurry Preparation ◽  
Good Agreement

Cup-cast method is a new method deals with semi-solid slurry preparation recently developed by the authors. In this method, suspension of globular solid particles in molten metal is prepared by controlling the nucleation and growth of solid-particles through the simplest and quickest techniques. In this method, heat transfer phenomenon plays an important role in governing the shape, size, and fraction of solid particles. In the current study, a heat transfer model was proposed and applied to Al-A356 alloy semi-solid slurry preparation. The heat transfer model was based on heat balance consideration between cup and slurry and it was in a good agreement with experimental results.

Semi-Solid Slurry Preparation without Additional Stirring, Cup-Cast Method

2006 ◽  
Vol 519-521 ◽  
pp. 1835-1840 ◽  
Author(s):  
Farshid Pahlevani ◽  
J. Yaokawa ◽  
Koichi Anzai
Keyword(s):  
Mass Transfer ◽  
Weight Reduction ◽  
Structural Investigation ◽  
A356 Alloy ◽  
High Strength ◽  
Nucleation And Growth ◽  
Solid Particles ◽  
Structural Applications ◽  
Semi Solid ◽  
Slurry Preparation

The needs for high-strength and lightweight structural materials have increased in automotive and aerospace structural applications. Semi-solid processed light alloys have satisfied these requirements because of processing advantages and significant weight reduction. Conventional semi-solid casting methods have got a wide variety of problems and difficulties. The cup-cast method that has been just developed is a novel process that make semi-solid casting as easy as pouring the water from a pitcher into a drinking glass, and avoid all the problem and difficulties of other semi-solid casting processes. Cup cast method is based on the heat and mass transfer and spherical equiaxed particles with controlling the nucleation and growth of solid particles were produced. In this study the different factor of this method was optimized by micro-structural investigation on the Al-A356 alloy. Pouring height and temperature, duration of pouring, and cup coating had played important roles in this method.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

2012 ◽  
Vol 516-517 ◽  
pp. 312-315
Author(s):  
Guang Hua Li ◽  
Hong Lei Liu ◽  
De Jian Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Heat Pipe ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Cooling Device ◽  
Transformer Design ◽  
Electrical Transformers ◽  
Good Agreement

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

Heat Transfer Modeling of Nanoparticle Packings on a Substrate

2018 ◽  
Author(s):  
Anil Yuksel ◽  
Edward T. Yu ◽  
Michael Cullinan ◽  
Jayathi Murthy
Keyword(s):  
Heat Transfer ◽  
Laser Power ◽  
Thermal Conductance ◽  
Heat Transfer Model ◽  
Experimental Result ◽  
Transfer Model ◽  
Heat Transfer Modeling ◽  
Interfacial Thermal Conductance ◽  
High Laser ◽  
Good Agreement

The temperature evolution of nanoparticle packings on a substrate under high laser power is investigated both experimentally and via numerical simulations. Numerical modeling of temperature distributions in copper nanoparticle packings on a glass substrate is performed and results are compared with experiment under 2.6 kW/cm2 laser power. A coupled electromagnetic-heat transfer model is implemented to understand the nanoparticle temperature distribution. Very good agreement between the coupled electromagnetic-heat transfer model and the experimental results is obtained by matching the interfacial thermal conductance, G, between the nanoparticles using the experimental result in the coupled electromagnetic-heat transfer model.

scholarly journals A two-stage heat transfer model for the peripheral layers of a grain store

2003 ◽  
Vol 7 (3) ◽  
pp. 147-164
Author(s):  
Alexsandar Antic ◽  
James M. Hill
Keyword(s):  
Heat Transfer ◽  
Present Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Two Stage ◽  
Peripheral Layer ◽  
Proposed Model ◽  
Grain Bulk ◽  
Insight Into ◽  
Good Agreement

An understanding of the flow of heat in grain store structures, in particular, within the peripheral layer, is important from many industrial perspectives. To analyse the heat transfer within such regions a mathematical model known as the two-stage heat transfer model is proposed. This model makes a distinction between the air and grain within the grain bulk, and thus takes into consideration the fact that the rate of heat transfer through the grain is different to that through the interstitial air surrounding the grain. Such a model lends itself to a solution via Laplace transforms and approximate analytical results are obtained for small and large times. In addition, the Stehfest numerical algorithm is used for the inversions and very good agreement is obtained between the two approaches. The present model is compared to a previously developed double-diffusivity heat transfer model by the authors, and good agreement is obtained. At present, no experimental data is available to validate the model as it is very difficult to measure the air and grain temperatures separately, particularly in the peripheral layer. The proposed model provides insight into the potential difference existing between the air and grain temperatures.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

Methodology to Characterize Heat Transfer Phenomena in Small Automotive Turbochargers: Experiments and Modelling Based Analysis

2014 ◽  
Author(s):  
J. R. Serrano ◽  
P. Olmeda ◽  
F. J. Arnau ◽  
A. Dombrovsky ◽  
L. Smith
Keyword(s):  
Heat Transfer ◽  
Standard Technique ◽  
Heat Transfer Model ◽  
Heat Fluxes ◽  
Experimental Methodology ◽  
Pollutant Emissions ◽  
Transfer Model ◽  
Great Effort ◽  
Heat Transfer Phenomenon ◽  
Comprehensive Study

These days great effort is devoted to the study of turbocharging in order to minimize fuel consumption and pollutant emissions of turbocharged reciprocating engines. Among all the processes taking place in small automotive turbochargers, the heat transfer phenomenon is one of the least analysed in a systematic way. However turbocharger heat transfer phenomena are very important at low engine loads. An accurate prediction of gas temperatures at turbine and compressor outlet and fluid temperatures at the water and oil outlet ports is not possible without considering heat transfer phenomena in the turbocharger. In the present work a comprehensive study of these phenomena is presented, showing their relevance compared to gas enthalpy variations through the turbomachinery. The study provides an experimental methodology to consider the different heat fluxes in the turbocharger and modelling them by means of a lumped capacitance heat transfer model. The input data required for the model is obtained experimentally by a proper combination of both steady and transient tests. These tests are performed in different test benches, in which compressible fluids (gas) and incompressible fluids (oil) are used in a given sequence. The experimental data allows developing heat transfer correlations for the different turbocharger elements. These correlations take into account all the possible heat fluxes, discriminating between internal and external heat transfer. In order to analyse the relative importance of heat transfer phenomena in the predictability of the turbocharger performance and the different related variables; model results, in hot and cold conditions, have been compared with those provided by the standard technique, consisting on using look up maps of the turbocharger. The analysis of these results evidences the highly diabatic operative areas of the turbocharger and it provides clearly ground rules for using hot or cold maps. In addition, paper conclusions advise about using or not a heat transfer model, depending on the turbocharger variables and the operative conditions that one desires to predict.

scholarly journals A Heat Transfer Model for the Production of Semi-Solid Billets with the SEED Process

2006 ◽  
Vol 519-521 ◽  
pp. 1525-1532 ◽  
Author(s):  
Josée Colbert ◽  
Dominique Bouchard
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Computer Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Inverse Technique ◽  
Solid Aluminum ◽  
Semi Solid ◽  
The Heat Transfer Coefficient

A heat transfer model was built to predict the temperature evolution of semi-solid aluminum billets produced with the SEED process. An inverse technique was used to characterize the heat transfer coefficient at the interface between the crucible and the semi-solid billet. The effect of several process parameters on the heat transfer coefficient was investigated with a design of experiments and the coefficient was inserted in a computer model. Numerical simulations were carried out and validated with experimental results.

Prediction of Heat Leakage Through Fish Hold Wall Sections

1989 ◽  
Vol 33 (03) ◽  
pp. 229-235
Author(s):  
De-qian Wang ◽  
Edward Kolbe
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
West Coast ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Model Design ◽  
Fishing Vessels ◽  
Heat Leakage ◽  
Good Agreement

Heat transfer through hold wall sections was investigated to improve prediction of heat leakage through fish hold boundaries of steel fishing vessels in the range of 14 to 32 m (45 to 105 ft). A finite-difference heat-transfer model was developed and eight fish hold wall sections representative of a 14 m (45 ft) boat were tested using the "guarded hot box" technique (ASTM C 236-80). Good agreement was obtained between the predicted and tested results. By applying the model, design curves of wall sections representative of typical West Coast steel vessels are presented.

Development of Cup-Cast Method; Semi-Solid Slurry Preparation without External Stirring Force

2006 ◽  
Vol 116-117 ◽  
pp. 358-361 ◽  
Author(s):  
Farshid Pahlevani ◽  
Y. Endo ◽  
J. Yaokawa ◽  
M. Itamura ◽  
M. Kikuchi ◽  
...  
Keyword(s):  
Automotive Industry ◽  
A356 Alloy ◽  
Solid Metal ◽  
Solid Particles ◽  
Heat Distribution ◽  
Metal Component ◽  
Near Net Shape ◽  
Semi Solid ◽  
Slurry Preparation ◽  
Micro Structures

Semi-Solid metal (SSM) processing is now considered a commercially successful manufacturing route producing millions of near net shape parts per annum for the automotive industry. Although semi-solid process is currently widely used as a manufacturing process which produces near net-shape metal component, the processes those used for the preparation of semi-solid slurry still take a great deal of time, energy and money. Cup cast method – recently developed by the authors – is able to make semi-solid slurry preparation as easy as pouring water from a pitcher into drinking glass. In this method globular solid particles are prepared by controlling the turbulence and heat distribution in the melt through pouring instead of applying certain external stirring forces, in other common method. In the current study, cup cast method applied to Al-A356 alloy using simple cylinder. Vital factors of this method were optimized by investigating micro-structures.

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