10 replies to this topic

[Yuriy M]

Hi. I'm writing a program that computes different results for a conductor such as rate of heat transfer in watts, coefficient of thermal conductivity, cross-sectional area in square meters, the kelvin temperatures on two sides and the thickness in meters. However, while the question shows me how to calculate the rate of heat transfer

H = kA(T2 - T1) / X

H = heat transfer in watts
k = coefficient of thermal conductivity
A = cross-sectional area in square meters
T2 = Kelvin temperature of one side
T1 = Kelvin temperature of another side
X = thickness in meters

I am unsure of the equation format for k, A, T2, T1 and X. I tried looking around for the precise format of the equations but to no avail. Any help would be appreciated. Thanks. :)

[Alexander]

Assuming you've all those variables defined, you can plug it directly in to C without modification.

If one variable were missing the formula would need to be modified for compensation of the missing variable, however I assume you do not.

Is it translating kA(T2-T1) that you have trouble writing in C?

Remember that C uses infix notation, so you need either + - / * between variables or parentheses.

[Waqar]

if u write the formula in compiler u should do it like this


H=k*A*(T2-T1)/X:D

[Yuriy M]

I think you guys misunderstood my question. What I'm asking is what the formula setup would be for k, A, T1, T2 and X in terms of conductivity. I'm already perfectly aware that H = kA(T2 - T1) / X. I'm referring more to the likes of:

k = H / A(T2 - T1) * X

Now, I'm not sure if the above equation that I put for k is correct or not. I'm assuming it may be.

[Waqar]

 h.png   978bytes   12 downloads

where H=  awd.png   448bytes   305 downloads is the rate of heat flow, k is the thermal conductivity, A is the total cross sectional area of conducting surface, ΔT is temperature difference, and x is the thickness of conducting surface separating the two temperatures.


 ggf.png   846bytes   9 downloads

ΔT / x is the temperature gradient

here it is the equation of thermal conductivity:cool:

Attached Files

•  fff.png   854bytes   14 downloads

[Waqar]

P (the rate of energy transfer) is proportional to the cross-sectional area A and the temperature difference, and inversely proportional to the length.
k, the thermal conductivity, is the proportionality constant, so:
P = kA(T2 - T1)/L:rolleyes:

[Yuriy M]

So, going by the terms of the equation, k would then be:

k = H * X / A * (T2 - T1)? :confused:

[Waqar]

yes i guess so:closedeyes:

[Yuriy M]

Thanks. Do you also have specific formulas to calculate Area (A), Temperatures (T1 and T2) and Thickness (X)?

[Waqar]

by the above formula of thermal conductivity or u want area by delta(T) and x?

[Yuriy M]

Yes, the Area (A) and Thickness (X).

BUMP: Okay, listen up! If you guys don't want to help me further, just say it! I don't need anybody here giving me the silent treatment! Have some balls and tell me that I'm on my own!

Edited by Yuriy M, 18 August 2011 - 05:23 PM.