Working out heat transfer flux in a pipe

In summary, the heat transfer flux in a pipe can be calculated using the formula Q/A, where Q is the heat transfer rate and A is the cross-sectional area of the pipe. The factors that affect heat transfer flux include the temperature difference between the fluid and the pipe wall, the thermal conductivity of the pipe material, and the fluid flow rate. To increase heat transfer flux, you can adjust these factors, as well as use materials with high thermal conductivity or increase the surface area of the pipe. The units of heat transfer flux are typically watts per square meter (W/m²) in the SI system or BTU per hour per square foot (BTU/hr-ft²) in the imperial system. Additionally, heat transfer flux can be negative
  • #1
sjh94
5
0
1. Question

upload_2017-2-16_13-11-51.png
2. The attempt at a solution

upload_2017-2-16_13-24-0.png


Now I'm not sure where to go next? Do I work out the local heat transfer coefficient at 1.2m or just the heat transfer coefficient? Using
h = Nu × k/x
or
h = Nu × k/d

Thanks, Sam.


 
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  • #2
If you have turbulent flow, is there a significant thermal entrance region, or does the heat transfer coefficient level off over a very short distance into the pipe? Under what circumstances would you use Nu k/x?
 

FAQ: Working out heat transfer flux in a pipe

How do you calculate heat transfer flux in a pipe?

The heat transfer flux in a pipe can be calculated using the formula Q/A, where Q is the heat transfer rate and A is the cross-sectional area of the pipe.

What factors affect heat transfer flux in a pipe?

The factors that affect heat transfer flux in a pipe include the temperature difference between the fluid and the pipe wall, the thermal conductivity of the pipe material, and the fluid flow rate.

How can I increase the heat transfer flux in a pipe?

To increase the heat transfer flux in a pipe, you can increase the temperature difference between the fluid and the pipe wall, increase the thermal conductivity of the pipe material, or increase the fluid flow rate. Additionally, using materials with high thermal conductivity or increasing the surface area of the pipe can also increase heat transfer flux.

What are the units of heat transfer flux?

The units of heat transfer flux are typically watts per square meter (W/m²) in the SI system or BTU per hour per square foot (BTU/hr-ft²) in the imperial system.

Can heat transfer flux be negative?

Yes, heat transfer flux can be negative. A negative heat transfer flux indicates that heat is being transferred out of the pipe, while a positive heat transfer flux indicates heat is being transferred into the pipe.

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