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Homework Help: Steady state temperature

  1. Nov 18, 2011 #1
    1. The problem statement, all variables and given/known data
    A fire in a room rapidly raises the temperature of the surface of the wall to a steady value of 1000°C. on the other side of the wall is a large warehouse, whose ambient air temperature is 20°C. If the wall is solid brick, 200 mm thick, with thermal conductivity of 0.72 W/m°C, what is the steady state temperature of the surface of the wall ( on the warehouse side) in °C. You may assume the heat transfer coeffiecient of the air in the warehouse is 12W/m^2°C

    2. Relevant equations

    d^2T/dx^2 =ρc dT/ kdt

    3. The attempt at a solution

    this is a second order differential equation.

    Please help me. thanks in advance!
  2. jcsd
  3. Nov 19, 2011 #2
    The equation for heat flow is
    dQ/dt = kA(Δ∅)/x
    Where dQ/dt = rate of heat flow in Watts (or Watts/m^2)
    k = thermal conductivity W/m
    A = cross sectional area (1m^2)
    (Δ∅)/x = (difference in temp)/thickness
    Hope this gets you started
  4. Nov 19, 2011 #3
    thank you technician :) i use different approarch in solving this problem. I used electrical analogy instead of solving the differentail equation.
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