pressure in inlet flare's tip

As per API 521:

Mach = 1.702x10^-5[W/(P·D)][ZT/(kM_w)]^0.5

Where:

Mach = Mach number

W= gas flow rate in pounds per hour

D = tip inside diameter in feet

P = tip out pressure in pounds per square inch absolute

Z = gas compressibility factor

T = absolute temperature in degrees Rankine

M_w = gas molecular weight

k = ratio of specific heats (C_p/C_v)

One may want to permit a velocity of up to 0.5 Mach for a peak, short-term, infrequent flow, with 0.2 Mach maintained for the more normal and possibly more frequent conditions for low pressure flares

Thank you for your attention

I don't understand you say that the P is atmospheric for sonic tip(high pressure)?

can i use the pressure of inlet fluid is 100 psig.and is this pressure effected in P(in equation)?

Mach no:0.65

Regards,

in API RP 521 not any recommendation about sonic flare.

i think it can mach : 0.8 approxmately because in sonic flare energy is need for flareless operation

best regards