This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Combination Air Relief Valve (Vacuum) Modeling - WaterCAD

We are modeling a raw water transmission line from a reservoir (lake) to a water treatment plant (discharge to clearwell open to atmosphere).  The line will siphon over the reservoir dam (model shows vacuum condition as expected).  Further down the hill we have serveral local high points where The overall gradient is downhill, but we have several local highpoints where combination air valves will be installed to break vacuum conditions and allow for gravity flow.  Currently for the segment of pipe downstream of the combination air valves the model shows high negative pressure, however this doesn't match our expectations that this flow would be partially full (gravity flow) with 0 pressure (atmospheric).  We have corrected the attached PDF with bold blue and red lines to show what we think the HGL and pressures should be in the "partial flow" sections of pipe.  Is this correct?  Is there a way to better model this so the WaterCAD model shows zero pressure for these sections?

75104.00 Upper Wrangell Raw Water Pipeline 2020.09.30.wtgPDF

75104.00 Upper Wrangell Raw Water Pipeline 2020.09.30.wtg

Parents Reply Children
No Data