Hi all,

Problem statement: I am trying to model water cavitation using Singhal model in fluent. Geometry : ( Pipe converges from 50 mm to 5mm-orifice). This pipe is on the suction side of the pump. 

This pipe is on the suction side of the pump. 

I set vapor pressure to 9600 Pa (as temp is 45-50 C)

I have a flow meter which shows 40 lpm flow and downstream pressure of -25inch of Hg (~85000pa). My upstream pressure gauge shows zero reading always. 

BC: set to pressure inlet and outlet.

1.) As my upstream gauge shows zero reading. what should be entered in fluent for pressure inlet BC? 

2.) What is total gauge pressure and initial gauge pressure ( FLUENT tutorial says TGP-IGP = axial velocity) How is it calculated? any literature support? Any clear explanation by equation?

3.) when I enter 1 bar as inlet pressure (since pressure gauge shows zero)  in TGP, what should be IGP?

4.) when I solve with velocity input, my solution has a divergence problem. 

5.) If I use high pressure (5 bar), I get lowest absolute pressure as 0.5 bar(which is not below vapor pressure). Does it mean that there is no cavitation and it is only turbulence( i see some bubbles and sound like marble collapse in the setup)? In this case, how do I validate my model? ( as I give both my inlet and out let pressure to software)