I'm trying to design a venturi tube that will have a pressure drop of 91525 Pascals where the inlet pressure is at 1 atm and the throat pressure is at 9800 Pascals. I calculated the minimum throat velocity need to have this drop assuming my inlet velocity is super small by doing the following.
What I get for $v_2$ is around 389 m/s.
This is over the speed of sound and I have been told that venturi tubes cant have supersonic flow at the throat. I have also been told that the velocity should stay under mach 0.3 as above mach 0.3 compressibility starts to become a problem.
I guess my question is, Is it possible to have a venturi tube that has a pressure drop of 91525 Pascals, why can't supersonic flow happen in the venturi tube, and if a venturi tube won't work what can I use to drop the pressure.
PS: The fluid in my tube is air