Thermal Radiation Questions

[WelshEngineer87]

Hi all,

I'm currently creating a 1D thermal model for assessing steady state heat transfer across a hollow cylinder with and without thermal insulation on the cylinder. The heat flow path is from internal gas flow through to external surface temperature for the cylinder or the insulation.

The cylinder is inside a sealed enclosure where the enclosure is supplied with airflow of 18m/s.

I have measured during testing the surface temperatures on the surface of the cylinder and the outside of the insulation. There is no measurement of ambient temperature in the box however have access to CFD to calculate ambient temperatures.

To calculate the heat flow rate in the 1D model the ambient temperature in the enclosure is required to determine total thermal resistance. Where should the ambient temperature be recorded from? i.e. how close to the cylinder for calculating heat transfer?

 

[IRstuff]

Not sure what you are asking; the "ambient" temperature is the starting temperature of the air, since the object adds heat to it and changes the temperature of the air.

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[chicopee]

There are a lot of examples in heat transfer textbooks about heat transfer thru cylinder walls. Do a research which is the best way to learn. Providing you with my copies of past problems dealing with this subject will not provide you with the knowledge that you need to know. Also do a search on the internet as there are multiple sources that will guide you. Researching subjects is one effective way to learn.

 

[racookpe1978]

Why a "1D model" Does it not have to be at a minimum of 2D (length and diameter) since the distribution is not exactly the same the length of the cylinder.

 

[goutam_freelance]

You can calculate the thermal boundary layer film thickness and measure the temperature clearing such thickness.