class 7

# class 7 - Transient Conduction The Lumped Capacitance...

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Transient Conduction: The Lumped Capacitance Method Chapter Five Sections 5.2 thru 5.3 Class 7

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What kind of situation is transient conduction? A solid experiences a sudden change in its thermal environment Quenching Charging Lumped capacitance Assume temperature is spatially uniform at any instant during the transient process Therefore we assume no temperature gradients
For this situation, what is the energy balance? g out in st st E E E t dE E + - = I II III IV a)I and II b)I and III c)I, II and III d)I and IV e)II, III and IV

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How do we use the energy balance to find our lumped capacitance approach?
Define a thermal time constant:

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Define a thermal time constant: What will happen if we increase R t ? a)A solid will respond more slowly to changes in its thermal environment b)A solid will respond more quickly to changes in its thermal environment c)The R t does not affect the response – only the lumped thermal capacitance
To determine total energy transfer Q after some time :

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Since –Q = ΔE st a)For quenching Q is positive and the solid experiences a
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## This note was uploaded on 08/13/2011 for the course CHEM 3210 taught by Professor Degrazia during the Fall '10 term at Colorado.

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class 7 - Transient Conduction The Lumped Capacitance...

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