stanier
Mechanical
- May 20, 2001
- 2,442
Hi,
I am seeking advice in respect of a planned syphon. The system has the following levels.
Dam level RL138m 30+m to dam wall
Dam wall 146m 15m over wall
Pipeline Outlet RL 122m Outlet is 130m from top of dam wall
Temperature 30C
Water
Pipeline DN710 PN 12.5 PE
Pipeline is relatively short. The system will be primed by a pump, isolated and then the siphon opened.
The software I am using predicts vacuum pressures greater than atmospheric at the high point through the dam. The gravity flow will be limited by the friction losses in the pipeline but velocities are still predicted at 6-7m/s.
My question is will the system be unstable as the water will boil at the high point? Or will the fluid move so fast as to drag any water vapour bubbles with it?
I have designed and built a similar system but it was connected to a pump suction that controlled the flow. It works perfectly. This system is just top drain a dam over the dam wall.
I am thinking a restriction at the outlet to provide some back pressure may keep the system pressure above the vapour pressure of the water.
ôThe beautiful thing about learning is that no one can take it away from you.ö
---B.B. King
I am seeking advice in respect of a planned syphon. The system has the following levels.
Dam level RL138m 30+m to dam wall
Dam wall 146m 15m over wall
Pipeline Outlet RL 122m Outlet is 130m from top of dam wall
Temperature 30C
Water
Pipeline DN710 PN 12.5 PE
Pipeline is relatively short. The system will be primed by a pump, isolated and then the siphon opened.
The software I am using predicts vacuum pressures greater than atmospheric at the high point through the dam. The gravity flow will be limited by the friction losses in the pipeline but velocities are still predicted at 6-7m/s.
My question is will the system be unstable as the water will boil at the high point? Or will the fluid move so fast as to drag any water vapour bubbles with it?
I have designed and built a similar system but it was connected to a pump suction that controlled the flow. It works perfectly. This system is just top drain a dam over the dam wall.
I am thinking a restriction at the outlet to provide some back pressure may keep the system pressure above the vapour pressure of the water.
ôThe beautiful thing about learning is that no one can take it away from you.ö
---B.B. King
