Radiation heat transfer in channel flow

In summary, the presence of radiation heat transfer between a fluid and a contacting surface is dependent on factors such as fluid temperature, flow conditions, and the material properties of the fluid and surface. In most cases, conduction and convection dominate the heat transfer process, but in certain scenarios, such as with high temperatures or large diameter tubes, radiation may also play a role. However, for gases at atmospheric pressure and liquids with high thermal conductivity, radiation is typically not a significant contributor to heat transfer.
  • #1
VYT
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TL;DR Summary
Does radiation heat transfer occurs between in a channel flow?
Hi guys, I am confused about the heat transfer mode of between two contacting material, especially in a channel flow.

Obviously, conduction or convection dominate the heat transfer process in the process with low object temperature .

But I am not sure if I have a fluid of 500 Kelvin, flowing in the the steel pipe that is exposed to air, does radiation heat transfer occurs between the fluid and the contacting surface?

The only reason I can think of to reject the idea above is that temperatures of two contacting materials are too closed that radiation is not occurring.

Am I right about it, and is there other reasons behind it? Thank you!
 
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  • #2
VYT said:
But I am not sure if I have a fluid of 500 Kelvin, flowing in the the steel pipe that is exposed to air, does radiation heat transfer occurs between the fluid and the contacting surface?
Generally thermal radiation contribution in your case would be small.

If your fluid is gas at atmospheric pressure, the radiation thermal resistance at 500K is similar to conductance thermal resistance of boundary layer in case of laminar flow, but most gases are transparent in thermal IR at length scale of centimetres, therefore not emitting IR efficiently. IR contribution may be important if you have very large diameter tube or very emissive mix of gases, preferable both. I. e. something like flue gas in chimney stack.

If your "fluid" is liquid, it have high enough thermal conductivity to make radiation transfer contribution negligible, due liquid becoming nearly isothermal with pipe.
 

Related to Radiation heat transfer in channel flow

What is radiation heat transfer in channel flow?

Radiation heat transfer in channel flow refers to the transfer of thermal energy through electromagnetic waves between two surfaces separated by a channel or gap. This type of heat transfer occurs in the absence of a medium or direct contact between the two surfaces.

How does radiation heat transfer differ from conduction and convection heat transfer?

Radiation heat transfer differs from conduction and convection heat transfer in that it does not require a medium or direct contact between the two surfaces. Instead, it occurs through electromagnetic waves, which can travel through a vacuum. Conduction and convection heat transfer, on the other hand, require a medium such as a solid, liquid, or gas to transfer thermal energy.

What factors affect the rate of radiation heat transfer in channel flow?

The rate of radiation heat transfer in channel flow is affected by several factors, including the temperature difference between the two surfaces, the surface area of the channel, the emissivity of the surfaces, and the distance between the two surfaces. The type of material and its properties also play a role in the rate of radiation heat transfer.

What are some applications of radiation heat transfer in channel flow?

Radiation heat transfer in channel flow has various applications, including in the design of heat exchangers, solar panels, and thermal insulation. It is also used in industries such as aerospace, automotive, and electronics for thermal management and heat exchange processes.

How is radiation heat transfer in channel flow calculated?

The rate of radiation heat transfer in channel flow can be calculated using the Stefan-Boltzmann law, which states that the heat transfer rate is proportional to the fourth power of the absolute temperature and the difference in emissivity between the two surfaces. Other factors, such as the surface area and distance between the two surfaces, can also be taken into account in the calculation.

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