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-   -   Best way to calculate bulk fluid temperature in case of steam-water flow (https://www.cfd-online.com/Forums/main/251868-best-way-calculate-bulk-fluid-temperature-case-steam-water-flow.html)

silviliril September 12, 2023 04:23

Best way to calculate bulk fluid temperature in case of steam-water flow
 
In order to get Heat Transfer Coefficient, I need to calculate bulk fluid temperature at different axial locations in a pipe flow boiling case. But, the getting bulk fluid temperature in two-phase flow doesn't seem straightaway. So, What will be the best strategy?

I am using RPI wall boiling model and post-processing is being done in tecplot.

Do I need to do area averaged or mass averaging or other suitable method? how to I combine phase-1 (liquid) and phase-2(vapor) temperatures into one?

LuckyTran September 13, 2023 00:33

Bulk temperature is defined as mass averaged

silviliril September 13, 2023 00:41

okay. Till now I have understood that mass flow averaged has to be considered. But, that can be found for single phase flow. what about two phase flow at cross section? How mass flow averaged temperature formula works for two-phase?

LuckyTran September 13, 2023 01:33

What happens if you have a glass of water with ice?


Bulk temperature was invented exactly to deal with these kinds of scenarios and yet you are questioning how bulk temperature would work as it was intended.

silviliril September 13, 2023 02:31

I just want to know if following formula is correct or not for bulk fluid temperature:

Code:

Tb=(Ti ui ρi Ai + Tj uj ρj Aj)/(ui ρi Ai + uj ρj Aj )
where, Ti=temperature of phase 1
ui=velocity of phase 1
ρi = density of phase 1
Ai = area occupied by phase 1
Same notations are for phase 2 with j.


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