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Identification of Interfacial Heat Transfer Coefficient During Casting

Jun 04, 2018

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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