Heat flow problem (copper pipe)

In summary, to find the heat flow through a copper bar with a cross sectional area of 4.40 cm2 and a length of 0.62 m, with one end at 1 °C and the other end at 97 °C, the thermal resistivity must be calculated by taking the inverse of the thermal conductivity. Then, using the thermal resistivity, the thermal resistance can be calculated using the formula R = (λ*L)/A. This value is then used in the thermal current formula I = ΔT/R, where ΔT is the difference in temperature measured in Kelvin. It is important to correctly convert the cross sectional area to meters before using it in calculations.
  • #1
BMcC
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Homework Statement



A copper bar with a cross sectional area of 4.40 cm2 and a length of 0.62 m has one end at 1 °C and the other end at 97 °C. Find the heat flow through the bar if the thermal conductivity of copper is 385 W/(m·K)

Homework Equations



R = (λ*L)/A

I = ΔT / R

k = 1/λ


R = resistance
λ = thermal resistivity
L = length of pipe
A = cross sectional area

I = thermal current
ΔT = change in temperature

k = thermal conductivity

3. My attempt

So first I converted the area 4.40 cm2 into 0.044 m2.

Then I converted the thermal conductivity given in the problem to thermal resistivity

k = 1/λ
λ = 1/k
= 1/385 W/(m·K) = 0.00259 mK/W

Using this value, the area, and the length from the problem, I used R = (λ*L)/A

R = (0.00259 mK/W)(0.62 m) / 0.044 m2
R = 0.0366 K/W

Now I plugged this R into the thermal current formula I = ΔT/R, where ΔT = 97 °C - 1 °C = 96 °C

The ΔT is measured in Kelvin, but is still a difference of 96 units.

I = 96K / 0.0366 K/W = 2622.95 W = 2622.95 J/s

This is incorrect apparently. Does anybody know where I might have went wrong?

Thanks!
 
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  • #2
Hello, BMcC. I haven't checked all of your numbers, but I did notice that you made a common mistake in converting 4.40 cm2 to m2.
 
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  • #3
Ah wow how silly of me. That changes everything. Thanks TSny!
 

1. What is the heat flow problem in a copper pipe?

The heat flow problem in a copper pipe refers to the transfer of thermal energy through the walls of a copper pipe when there is a difference in temperature between the inside and outside of the pipe.

2. How does heat flow occur in a copper pipe?

Heat flow in a copper pipe occurs through a process called conduction, where thermal energy is transferred from one particle to another without the actual movement of the particles.

3. What factors affect heat flow in a copper pipe?

The rate of heat flow in a copper pipe is affected by the temperature difference between the inside and outside of the pipe, the thickness of the pipe walls, and the thermal conductivity of the copper material.

4. What is the thermal conductivity of copper?

The thermal conductivity of copper is approximately 401 W/mK at room temperature. This means that copper is a good conductor of heat and can transfer thermal energy quickly.

5. How can the heat flow problem in a copper pipe be managed?

The heat flow problem in a copper pipe can be managed by using insulation materials around the pipe to reduce heat loss or gain, or by using a heat exchanger to transfer the heat from the pipe to another medium without direct contact.

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