7 replies to this topic

[Deepali]

Hi all,

I am working with a group on "Flare-Radiation Study Project" for an existing platform. And I am given an excel-spreadsheet created by someone else to calculate the 3D points radiation data for the current flaring data. First thing I am asked to validate the spreadsheet for Project use which I almost have finished doing except the Flame length calculations.
it uses following three terms & res. formula which I couldn't find in API/GPSA, etc.
I would greatly appreciate any guidance/help to validate the source/s of those formulas/equations.

API FLAME LENGTH: 0.00604*(heat release)^0.4776

SONIC FLAME LENGTH: 0.004503 * (heat release)^0.459882

EFFECTIVE FLAME LENGTH: (1- Tip MACH Number) *API Flame Length + (Tip MACH Number * Sonic Flame Length)


I refered API 521 (2007), it uses a plot betn flame length & heat release (fig.7 & 8) & its based on some plant-scale experimental work on flames; is there any empirical equation for it?

Does anyone have any information for me?

Thanks & Regards,

[gvdlans]

Milton Beychok fitted the datapoints from API STD 521 in his book "fundamentals of stack gas dispersion". The result for flame height is shown on the Book cover :

hfv = 0.0042*Q^0.478

Q is heat released (lower heating value) in BTU/hr
hfv is flame height in feet

Since he assumed a 45 degrees angle, the flame length is:

flame length = 0.0059*Q^0.478

(note that 0.0059=0.0042*sqrt(2))

which is very similar to your first equation. Probably someone else curve fitted this equation on the datapoints read from the API 521 graph (figure 8 on page 82).

I don't know what you mean with sonic flame length or effective flame length.

[Deepali]

Thank you so much gvdlans!

thats really helpful.
I am trying define the term "SONIC FLAME LENGTH" used in the calculations which is not present in API but not getting a clue.
Please let me know if you can guide on it too.
Once again thanks a ton!

[Deepali]

Thanks Shanesheoran!