Identification of Interfacial Heat Transfer Coefficient During Casting

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IDENTIFICATION OF INTERFACIAL HEAT TRANSFER CO(IHTC) DURING CASTING SOLIDIFICATION BASED ON INV

CONDUCTION MODEL

K Sriniv13M

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Presentation Outline:

Why Interfacial heat transfer coefficient Why Inverse heat transfer method What is interfacial heat transfer coefficient Case study Results

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The interfacial heat transfer coefficients arerequired for accurate simulation of castingprocesses.

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Simulation?????

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Advantages

Cost. Level of Detail.

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Inverse Heat transfer???

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Inverse Problem:

An Inverse Problem is one of determiningunknown causes on the basis of observedeffects

Contrast with a Direct Problem of compusystem responses based on specified inputs

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Lets us consider a simple heattransfer problem.

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Direct Problem Determination of the temperature distribution T(x, t

in the interior region of the solid, as a function oftime and position.

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Inverse Problem:

Consider a problem similar to that, but theboundary condition function f ( t ) at thesurface x = 0 is unknown, while all the otherquantities appearing in equations, such as

F(x), k, p and cp, are known. We then wish to determine the unknown

boundary condition f(t).

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Inverse Problem(contd.)

To compensate for lack of information we wilmeasure temperature at a internal point atdifferent times.

We will try toestimate

the surface conditibased on this data.

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Class of Inverse Problem.

Inverse Boundary Problem Determine unknown action at a physical

boundary; typically a function of time Inverse Coefficient Problem

Determine unknown coefficients, such asthermophysical properties

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Interfacial Heat transfer coefficient

The coefficient that describes Heat transfer atinterface.

For castings this interface properties willbe dynamic.

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Difficulties in direct Estimation of Heattransfer coefficient in casting: Contacting pressure Surface oxides Roughness of surfaces Coating material. Gap formation by deformation of casting and

mold.

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Experimental Setup:

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Mathematical Model:Governing Equation for FEM solver:

Boundary conditions:

Interfacial Heat transfer coeffi

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Inverse Problem Algorith

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Results:

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Questions

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THANK YOU