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Heating solid to high temperature

  1. Aug 5, 2009 #1
    Hi,

    I want to electrically heat a uniform block of a known material to a high temperature (about 2000 K). I want to get a rough idea of how much electrical energy I need to supply to raise the material to this temperature so as to gauge what apparatus I will need. How would I go about this?

    Any help would be much appreciated :)

    Thanks

    Fish
     
  2. jcsd
  3. Aug 5, 2009 #2
    At equilibrium the power radiated should be equal to the electrical power input.
    The power radiated is given by Stefan-Boltzmann law.
    P_rad=Sigma*T^4*Area
    Where Sigma is the S-B constant and "Area" is the surface area of the object.
    If the object is not a black body you need to multiply by a correction factor.
    It will give you a minimum estimate because heat will be also lost by convection and air conduction but I suppose that at 2000 degrees the radiation will be the main factor (if the object is in air and not in some liquid).
     
  4. Aug 6, 2009 #3

    Mapes

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    This will give an estimate of the steady state power P required once the object is heated. To estimate the total energy needed, multiply the object's heat capacity C by the temperature increase [itex]\Delta T[/itex] (assuming no phase change occurs). The energy required for heating the object in time t will be between [itex]C\Delta T[/itex] and [itex]C\Delta T+Pt[/itex]. More exact estimates are possible, but this gives a good first approximation.
     
  5. Aug 6, 2009 #4
    Hello fish, from your post I am imagining a largish metal block and difficulties in heating this electrically .Could you not use something like a furnace?If the shape,size and nature of the metal are irrelevant you could use an ordinary filament light bulb.In normal use the filament can reach temperatures in excess of 2000 degrees.
     
  6. Aug 6, 2009 #5
    Hi guys,

    Thanks for your replies; I only wanted a quick rough idea of how to work this out so they were really helpful.

    Dadface, the furnace is an option but I wanted to work this out before commiting to anything. :)

    Thanks again guys.

    Fish
     
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