Modeling Vortechs

[jev2740]

Modeling an offline vortech unit with a bypass for the first time in hydrocad and need some advice on how to go about it. the bypass is provided at an upstream manhole; outlet above the inlet to the vortech to a down stream manhole. i have tried a number of different ways but dont see the results i was expecting altough it seems that it works

 

[psmart]

Sorry - I don't understand your question...

Remember that a vortex valve is modeled in HydroCAD as a pond outlet device, so you need to think carefully about how you define the "pond" storage and your outlet controls. I assume your bypass would be a separate outlet device, such as a weir or orifice.

If you have questions about a specific model you may want to send the file to HydroCAD support. Also please see the paragraph on "offline storage" at

http://www.hydrocad.net/pondstore.htm

 

[jev2740]

no it is not a vortex valve typically used as an outlet device it is a vortech unit used as a pretreatment device to seperate solids and sediment prior to entry into the pond, in this case the pond is subsurface detention.

 

[psmart]

I either case, the only way to model it in HydroCAD is as an outlet device on a "pond".

It sounds like the "pond" will be the upstream manhole, which will have two outlet devices: The Vortech and an overflow device. The overflow could be modeled as a weir or orifice.

 

[jev2740]

thats the way i have it modeled. was looking to see if there is a stage discharge report available for these devices to import similar to those for the vortex valve.

 

[psmart]

I assume you've checked the list of predefined devices? (Special Outlet & Load From File) If it's not there, you will need to enter the stage-discharge data by hand.

 

[RWF7437]

Doesn't the manufacturer have this data ? You said you were checking so maybe you've already asked them ? Have you also tried modeling this arrangement in Hydraflow Hydrographs 2007 ?

good luck

 

[jev2740]

yes i have checked the special outlets and it is not included, the manufacturer can provided the data to me but i have not recieved it yet. I am back in the office this morning and what i will try first is raising the bypass invert to the top of the device to take full advantage of the head put on the outlet of the device.
the way the system is arragned is: manhole with 8" to the vortech and bypass to the downstream manhole with the 8" inlet coming back "online" at that manhole, which is the arrangment required by the NYSDEC for this device.

 

[ptmoss]

Wouldn't you be modeling it as two ponds? The first would be the manhole with the Vortex and overflow outlets and the second would be the subsurface detention pond?

 

[jev2740]

it is modeled as two ponds, thats not really the problem

 

[ptmoss]

Then just the actual flow through the Vortex?

 

[jev2740]

yes the unit has a cfs limit of 1.6 i need to design it for a minimum of .86cfs. what i am seeing is that you can expect some settling in the unit during the WQv event and the bypass will need to be above the highest point of storag in the unit for the unit to be most effeciant in terms of treatment.
again the vortech should not be confused with the vortex, they are separate entities.

 

[ptmoss]

Gotcha. Sorry about my typing. I'm not that intimately familiar with those units. Sounds like the manufacturers data would be the ticket. Good luck with it!