Is specific heat capacity always ignored in Steady State

In summary, the conversation discusses simulating a forced convection cooling problem with a fan and assessing the temperature of the outlet air. The main question is whether the volumetric specific heat capacity of the air is relevant in this scenario. The expert explains that under steady state conditions, the SHC of air affects the temperature increase of the air and can be estimated for accurate results.
  • #1
C989hris
Hi,

I want to simulate a forced convection cooling problem. Air at ambient temperature is forced through a fan into a system to cool electronics and I would like to assess the temperature of the outlet air. Actually I'm interested in the delta between the ambient and outlet temperature. This will be accessed as steady state. So my question is: is the volumetric specific heat capacity of the air relevant?

I feel like it is relevant because if I run the simulation at a higher ambient temperature the volumetric specific heat capacity gets lower and therefore the delta between ambient and outlet temperature will increase, is that correct?

Thanks
 
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  • #2
Yes it's relevant.

Under steady state conditions, in a unit of time the electronics will dissipate a fixed amount of energy into a fixed amount of air increasing its temperature. How much it increases depends on the SHC of the air. So your input and output temperatures will depend on the SHC of the air.

However the SHC of air doesn't very much with temperature. Usually you can estimate the average temperature and look up the SHC of that and get reasonably accurate results.
 

1. What is specific heat capacity and why is it important?

Specific heat capacity is the amount of heat energy required to raise the temperature of a material by 1 degree Celsius. It is important for understanding how materials respond to changes in temperature and for calculating heat transfer in various systems.

2. What is steady state and how does it relate to specific heat capacity?

Steady state refers to a condition where all variables in a system remain constant over time. In this state, the rate of heat transfer into a material is equal to the rate of heat transfer out, so the specific heat capacity is not a factor in the overall heat transfer calculations.

3. Why is specific heat capacity sometimes ignored in steady state?

Specific heat capacity is often ignored in steady state because it is assumed that the material has reached a constant temperature and no further heat transfer is occurring. In this case, the specific heat capacity does not affect the overall heat transfer calculations.

4. Are there any situations where specific heat capacity should not be ignored in steady state?

Yes, there are some situations where specific heat capacity should not be ignored in steady state. For example, in systems with high thermal inertia or when significant changes in temperature occur over time, the specific heat capacity may need to be considered in calculating heat transfer.

5. How does specific heat capacity impact the design of thermal systems?

Specific heat capacity is an important factor to consider in the design of thermal systems, as it affects the amount of heat energy required to raise the temperature of a material. Understanding the specific heat capacity of different materials can help in selecting the most efficient materials for a given application and in designing systems that can effectively handle changes in temperature over time.

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