Heat transfer equation - formulation

In summary, the conversation discusses a device that is heated from the inside and loses heat to the surroundings. The speaker wants to calculate the heat capacity and heat loss coefficient of the device using the equation dQ = CdT1 + γ(dT2)dt, but is unsure of the meaning of dT in the expression γ(dT2)dt. They seek clarification on whether it represents the temperature differential or the instantaneous temperature of the device minus the temperature of the surroundings.
  • #1
rammer
23
0
Hi, I have a device which is heated from inside by constant heat (let's say by Joule's heat - UIt). Some heat causes temperature rise of the device, some is lost into surroundings through device's surface. I measured how temperature of the device varies with time and I want to calculate constants like heat capacity of the device and heat loss coefficient.

But I'm not sure whether my equation is correct:

dQ = CdT1 + γ(dT2)dt

dQ=UIdt
C - heat capacity of the device
γ - heat loss coefficient
dt - time differential
dT1 - temperature differential (of the device per dt)

I'm confused about last expression in the equation: What does dT in the expression γ(dT2)dt mean? Is it the same as dT1 or is it rather instantaneous temperature of the device minus temperature of surroundings?
 
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  • #2
Anyone? I just need in what form/terms we express heat loss...
 

FAQ: Heat transfer equation - formulation

1. What is the heat transfer equation and why is it important in science?

The heat transfer equation is a fundamental equation in thermodynamics that describes the transfer of thermal energy from one system to another. It is important in science because it helps us understand and predict how heat is transferred between objects and systems, and is crucial in many fields such as engineering, physics, and chemistry.

2. What is the general form of the heat transfer equation?

The general form of the heat transfer equation is q = kAΔT/Δx, where q is the heat transfer rate, k is the thermal conductivity, A is the cross-sectional area, ΔT is the temperature difference, and Δx is the distance over which the heat is transferred.

3. How is heat transfer equation used in real-life applications?

The heat transfer equation is used in various real-life applications, such as designing and optimizing heating and cooling systems, calculating energy efficiency and heat loss in buildings, predicting temperature distribution in industrial processes, and understanding weather patterns.

4. What are the three modes of heat transfer described by the heat transfer equation?

The three modes of heat transfer described by the heat transfer equation are conduction, convection, and radiation. Conduction is the transfer of heat through a solid material, convection is the transfer of heat through a fluid (either by natural or forced movement), and radiation is the transfer of heat through electromagnetic waves.

5. How is the heat transfer equation related to the first and second laws of thermodynamics?

The heat transfer equation is closely related to the first and second laws of thermodynamics. The first law states that energy cannot be created or destroyed, only transferred or converted. The heat transfer equation describes the transfer of thermal energy, which is a form of energy. The second law states that heat always flows from a higher temperature to a lower temperature, and the heat transfer equation follows this principle by including the temperature difference in its formulation.

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