{"id":275256,"date":"2023-03-17T06:10:37","date_gmt":"2023-03-17T06:10:37","guid":{"rendered":"\/forum\/?post_type=topic&p=275256"},"modified":"2023-03-17T06:10:37","modified_gmt":"2023-03-17T06:10:37","slug":"negative-total-pressure-in-pump-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-total-pressure-in-pump-simulation\/","title":{"rendered":"Negative total pressure in pump simulation"},"content":{"rendered":"

I have a simulation for axial flow pump with the following details;
Inlet BC = Pressure (0.4 bar)
Outlet BC = massflow rate ( 6000 m3\/hr)
Ref. Pressure = 0 atm
Kw SST Turbulence model
Steady state simulation.
Y+ = ~2<\/p>\n

When I plot contours of total pressure, very large negative pressure values are observed ( in the orders of -500 KPa \/ -5.0 bar ). 
How can this be possible when absolute pressure cannot be < 0 in real world.<\/p>\n

We know, In Ansys, The total pressure is = static + dynamic 
and Absolute pressure = Ref. operating pressure + static pressure<\/p>\n

 <\/p>\n

<\/p>\n

    \n
  1. In the Total Pressure contor, -ve pressure values are observed (at the impeller) which is expected as the impeller egde will have a lower pressure naturally.<\/li>\n
  2. But looking at the second picture (i.e. Total pressure contour at Impeller blades), very large -ve pressures are observed which cannot be physically possible. <\/li>\n
  3. What inference can i deduce from the above contours. (for e.g. cavitation? incorrect physics settings? numerical error?)<\/li>\n<\/ol>\n

    Any comments \/ suggestions would be apperciated as it will help me make my case stronger.
    Thank you<\/p>\n","protected":false},"template":"","class_list":["post-275256","topic","type-topic","status-closed","hentry","topic-tag-absolute-pressure-1","topic-tag-ansys-cfx","topic-tag-cavitation","topic-tag-incompressible-flow","topic-tag-pump","topic-tag-pump-impeller-1","topic-tag-steady-state","topic-tag-total-pressure"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t