Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion
Discussion Forum : Heat Transfer, Refrigeration and Air Conditioning - Section 1 (Q.No. 14)
14.
Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)
Discussion:
5 comments Page 1 of 1.
Swapnil said:
1 decade ago
Thermal conductivity of material is taken as negative (-ve sign should be there) because heat always flow from higher temperature to lower temperature, so the value of temperature gradient is negative, amount heat flow is always positive value.
Rayudu babu T.C said:
1 decade ago
Rate of heat exchange is directly proportional to temperature gradient.
Suzer said:
6 years ago
Here dt/dx indicates the temperature difference so it can be + or -.
Rama krishna said:
1 decade ago
Rate of heat flux is directly proportional to temperature gradient.
Avaneesh said:
1 decade ago
Yes ! SWAPNIL is right. The formula must contain a negative sign.
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