Design of "Trash Racks" for High volum flow.... :(
Design of "Trash Racks" for High volum flow.... :(
(OP)
Throwing this question out there...
We have a high capacity volume discharged located on a dam outlet, 120000gpm. The inlet Pipe is 36" dia and is defined as projected...
NOW.... if you have to design an inlet rack.. such that it flows perp fromt he inlet pipe itself. think like a box attached to the end of a pipe with just the bottom open. how large would it have to be..
need a realationship between rydralic radius and flow of both the racking and pipe???
We have a high capacity volume discharged located on a dam outlet, 120000gpm. The inlet Pipe is 36" dia and is defined as projected...
NOW.... if you have to design an inlet rack.. such that it flows perp fromt he inlet pipe itself. think like a box attached to the end of a pipe with just the bottom open. how large would it have to be..
need a realationship between rydralic radius and flow of both the racking and pipe???
RE: Design of "Trash Racks" for High volum flow.... :(
RE: Design of "Trash Racks" for High volum flow.... :(
I’m thinking that sum of the individual areas of the openings of the racking would have to be significantly larger than that of the pipe. the pipe's Hydraulic Radius is approximately 9" where an individual opening on the racking is 0.5" approx. because the Hydraulic radius of the rack does not change the larger it gets (The area of the racking is just multiplies of little area/ little perimeters)I am looking for some sort of relationship between the racks Rh and Pipes Rh.
I am basically trying to reduce the K value of the trash rack to zero.
what do you peoples think?
RE: Design of "Trash Racks" for High volum flow.... :(
This product does not go up to 36":
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but the design does try to divert larger objects off of the inlet.
RE: Design of "Trash Racks" for High volum flow.... :(
RE: Design of "Trash Racks" for High volum flow.... :(
HDS 5 (culvert check the safety section for how to clculate flow loss through safety (or debris) grates
HEC 9 on debris protection for bridges and culverts. The FHA has some very nice trash racks. Also debris deflectors which I like in more urban areas.
You always have head loss, though say a post and cable system that is about 10 times the culvert width tends to have a minimal loss, but as cvg suggests the biggest loss is typically the debris stuck to the rack.
I look at a lot of trash racks. One item I would suggest is to look at nearby dams or highway culverts. Every area has different trash (construction material to cornstalks with a lot of sediment in the middle).
RE: Design of "Trash Racks" for High volum flow.... :(
RE: Design of "Trash Racks" for High volum flow.... :(
I looked up the head loss as a percentage of 100' length of steel pipe at 36"dia at 120000gpm (approx 10%). Equated it to that of a pipe of a similar hydraulic Radius of the small grating openings( approx 1" x 4"), took that gpm and divided it into the 120000gpm, and got a resulting number of small openings.
Ended up with an intake of 8' x 12' taking in account of 25% blockage safety factor.
RE: Design of "Trash Racks" for High volum flow.... :(
http:/