hello,everyone

Who can tell me how to calculate sonic flare tip?
including flame length and heat radiation, etc.
can pipe flare tip be used as sonic flare tip?
I don't find there is method of calculation about sonic flare tip in API521 .

thanks
ljl

First thing you have to understand what is subsonic and sonic tip.

Normal flare tip is subsonic (MA<1) pipe flare tip where the exit velocity is lower than sonic velocity.

Sonic tip (MA=1) being a pipe with the flow increase upto the velocity reach sonic velocity.
Base on this understanding, you may simulate a sonic tip.

I also have heard of supersonic (MA>1) flare tip. I have simulated this supersonic flare tip, not much benefits using supersonic flare tip from radiation perspective.